stringcase 1.0.0

// Copyright (C) 2024-2026 Takayuki Sato. All Rights Reserved.
// This program is free software under MIT License.
// See the file LICENSE in this distribution for more details.

use crate::options::Options;
use crate::upperize::upperize;

/// Converts the input string to macro case with the specified options.
///
/// ```rust
///     let opts = stringcase::Options{
///       separate_before_non_alphabets: true,
///       separate_after_non_alphabets: true,
///       separators: "",
///       keep: "",
///     };
///     let result = stringcase::macro_case_with_options("fooBar123Baz", &opts);
///     assert_eq!(result, "FOO_BAR_123_BAZ");
/// ```
#[inline(always)]
pub fn macro_case_with_options(input: &str, opts: &Options) -> String {
    upperize::<'_'>(input, opts)
}

/// Converts the input string to macro case.
///
/// It treats the end of a sequence of non-alphabetic characters as a word boundary, but not
/// the beginning.
///
/// ```rust
///     let result = stringcase::macro_case("fooBar123Baz");
///     assert_eq!(result, "FOO_BAR123_BAZ");
/// ```
#[inline(always)]
pub fn macro_case(input: &str) -> String {
    let opts = Options {
        separate_before_non_alphabets: false,
        separate_after_non_alphabets: true,
        separators: "",
        keep: "",
    };
    upperize::<'_'>(input, &opts)
}

/// Converts the input string to macro case with the specified separator characters.
#[doc(hidden)]
#[deprecated(since = "0.4.0", note = "Should use macro_case_with_options instead")]
#[inline(always)]
pub fn macro_case_with_sep(input: &str, seps: &str) -> String {
    let opts = Options {
        separate_before_non_alphabets: false,
        separate_after_non_alphabets: true,
        separators: seps,
        keep: "",
    };
    upperize::<'_'>(input, &opts)
}

/// Converts the input string to macro case with the specified characters to be kept.
#[doc(hidden)]
#[deprecated(since = "0.4.0", note = "Should use macro_case_with_options instead")]
#[inline(always)]
pub fn macro_case_with_keep(input: &str, kept: &str) -> String {
    let opts = Options {
        separate_before_non_alphabets: false,
        separate_after_non_alphabets: true,
        separators: "",
        keep: kept,
    };
    upperize::<'_'>(input, &opts)
}

/// Converts the input string to macro case.
///
/// It treats the beginning and the end of a sequence of non-alphabetic characters as a word
/// boundary.
#[doc(hidden)]
#[deprecated(since = "0.4.0", note = "Should use macro_case_with_options instead")]
#[inline(always)]
pub fn macro_case_with_nums_as_word(input: &str) -> String {
    let opts = Options {
        separate_before_non_alphabets: true,
        separate_after_non_alphabets: true,
        separators: "",
        keep: "",
    };
    upperize::<'_'>(input, &opts)
}

#[cfg(test)]
mod tests_of_macro_case {
    use super::*;

    #[test]
    fn convert_camel_case() {
        let result = macro_case("abcDefGHIjk");
        assert_eq!(result, "ABC_DEF_GH_IJK");
    }

    #[test]
    fn convert_pascal_case() {
        let result = macro_case("AbcDefGHIjk");
        assert_eq!(result, "ABC_DEF_GH_IJK");
    }

    #[test]
    fn convert_snake_case() {
        let result = macro_case("abc_def_ghi");
        assert_eq!(result, "ABC_DEF_GHI");
    }

    #[test]
    fn convert_kebab_case() {
        let result = macro_case("abc-def-ghi");
        assert_eq!(result, "ABC_DEF_GHI");
    }

    #[test]
    fn convert_train_case() {
        let result = macro_case("Abc-Def-Ghi");
        assert_eq!(result, "ABC_DEF_GHI");
    }

    #[test]
    fn convert_macro_case() {
        let result = macro_case("ABC_DEF_GHI");
        assert_eq!(result, "ABC_DEF_GHI");
    }

    #[test]
    fn convert_cobol_case() {
        let result = macro_case("ABC-DEF-GHI");
        assert_eq!(result, "ABC_DEF_GHI");
    }

    #[test]
    fn convert_with_keeping_digits() {
        let result = macro_case("abc123-456defG89HIJklMN12");
        assert_eq!(result, "ABC123_456_DEF_G89_HI_JKL_MN12");
    }

    #[test]
    fn convert_with_symbols_as_separators() {
        let result = macro_case(":.abc~!@def#$ghi%&jk(lm)no/?");
        assert_eq!(result, "ABC_DEF_GHI_JK_LM_NO");
    }

    #[test]
    fn convert_when_starting_with_digit() {
        let result = macro_case("123abc456def");
        assert_eq!(result, "123_ABC456_DEF");

        let result = macro_case("123ABC456DEF");
        assert_eq!(result, "123_ABC456_DEF");

        let result = macro_case("123Abc456Def");
        assert_eq!(result, "123_ABC456_DEF");
    }

    #[test]
    fn convert_empty_string() {
        let result = macro_case("");
        assert_eq!(result, "");
    }
}

#[cfg(test)]
mod tests_of_macro_case_with_options {
    use super::*;

    mod non_alphabets_as_head_of_a_word {
        use super::*;

        #[test]
        fn convert_camel_case() {
            let opts = Options {
                separate_before_non_alphabets: true,
                separate_after_non_alphabets: false,
                separators: "",
                keep: "",
            };
            let result = macro_case_with_options("abcDefGHIjk", &opts);
            assert_eq!(result, "ABC_DEF_GH_IJK");
        }

        #[test]
        fn convert_pascal_case() {
            let opts = Options {
                separate_before_non_alphabets: true,
                separate_after_non_alphabets: false,
                separators: "",
                keep: "",
            };
            let result = macro_case_with_options("AbcDefGHIjk", &opts);
            assert_eq!(result, "ABC_DEF_GH_IJK");
        }

        #[test]
        fn convert_snake_case() {
            let opts = Options {
                separate_before_non_alphabets: true,
                separate_after_non_alphabets: false,
                separators: "",
                keep: "",
            };
            let result = macro_case_with_options("abc_def_ghi", &opts);
            assert_eq!(result, "ABC_DEF_GHI");
        }

        #[test]
        fn convert_kebab_case() {
            let opts = Options {
                separate_before_non_alphabets: true,
                separate_after_non_alphabets: false,
                separators: "",
                keep: "",
            };
            let result = macro_case_with_options("abc-def-ghi", &opts);
            assert_eq!(result, "ABC_DEF_GHI");
        }

        #[test]
        fn convert_train_case() {
            let opts = Options {
                separate_before_non_alphabets: true,
                separate_after_non_alphabets: false,
                separators: "",
                keep: "",
            };
            let result = macro_case_with_options("Abc-Def-Ghi", &opts);
            assert_eq!(result, "ABC_DEF_GHI");
        }

        #[test]
        fn convert_macro_case() {
            let opts = Options {
                separate_before_non_alphabets: true,
                separate_after_non_alphabets: false,
                separators: "",
                keep: "",
            };
            let result = macro_case_with_options("ABC_DEF_GHI", &opts);
            assert_eq!(result, "ABC_DEF_GHI");
        }

        #[test]
        fn convert_cobol_case() {
            let opts = Options {
                separate_before_non_alphabets: true,
                separate_after_non_alphabets: false,
                separators: "",
                keep: "",
            };
            let result = macro_case_with_options("ABC-DEF-GHI", &opts);
            assert_eq!(result, "ABC_DEF_GHI");
        }

        #[test]
        fn convert_with_digits() {
            let opts = Options {
                separate_before_non_alphabets: true,
                separate_after_non_alphabets: false,
                separators: "",
                keep: "",
            };
            let result = macro_case_with_options("abc123-456defG89HIJklMN12", &opts);
            assert_eq!(result, "ABC_123_456DEF_G_89HI_JKL_MN_12");
        }

        #[test]
        fn convert_with_symbols_as_separators() {
            let opts = Options {
                separate_before_non_alphabets: true,
                separate_after_non_alphabets: false,
                separators: "",
                keep: "",
            };
            let result = macro_case_with_options(":.abc~!@def#$ghi%&jk(lm)no/?", &opts);
            assert_eq!(result, "ABC_DEF_GHI_JK_LM_NO");
        }

        #[test]
        fn convert_when_starting_with_digit() {
            let opts = Options {
                separate_before_non_alphabets: true,
                separate_after_non_alphabets: false,
                separators: "",
                keep: "",
            };
            let result = macro_case_with_options("123abc456def", &opts);
            assert_eq!(result, "123ABC_456DEF");

            let result = macro_case_with_options("123ABC456DEF", &opts);
            assert_eq!(result, "123ABC_456DEF");

            let result = macro_case_with_options("123Abc456Def", &opts);
            assert_eq!(result, "123_ABC_456_DEF");
        }

        #[test]
        fn convert_empty_string() {
            let opts = Options {
                separate_before_non_alphabets: true,
                separate_after_non_alphabets: false,
                separators: "",
                keep: "",
            };
            let result = macro_case_with_options("", &opts);
            assert_eq!(result, "");
        }
    }

    mod non_alphabets_as_tail_of_a_word {
        use super::*;

        #[test]
        fn convert_camel_case() {
            let opts = Options {
                separate_before_non_alphabets: false,
                separate_after_non_alphabets: true,
                separators: "",
                keep: "",
            };
            let result = macro_case_with_options("abcDefGHIjk", &opts);
            assert_eq!(result, "ABC_DEF_GH_IJK");
        }

        #[test]
        fn convert_pascal_case() {
            let opts = Options {
                separate_before_non_alphabets: false,
                separate_after_non_alphabets: true,
                separators: "",
                keep: "",
            };
            let result = macro_case_with_options("AbcDefGHIjk", &opts);
            assert_eq!(result, "ABC_DEF_GH_IJK");
        }

        #[test]
        fn convert_snake_case() {
            let opts = Options {
                separate_before_non_alphabets: false,
                separate_after_non_alphabets: true,
                separators: "",
                keep: "",
            };
            let result = macro_case_with_options("abc_def_ghi", &opts);
            assert_eq!(result, "ABC_DEF_GHI");
        }

        #[test]
        fn convert_kebab_case() {
            let opts = Options {
                separate_before_non_alphabets: false,
                separate_after_non_alphabets: true,
                separators: "",
                keep: "",
            };
            let result = macro_case_with_options("abc-def-ghi", &opts);
            assert_eq!(result, "ABC_DEF_GHI");
        }

        #[test]
        fn convert_train_case() {
            let opts = Options {
                separate_before_non_alphabets: false,
                separate_after_non_alphabets: true,
                separators: "",
                keep: "",
            };
            let result = macro_case_with_options("Abc-Def-Ghi", &opts);
            assert_eq!(result, "ABC_DEF_GHI");
        }

        #[test]
        fn convert_macro_case() {
            let opts = Options {
                separate_before_non_alphabets: false,
                separate_after_non_alphabets: true,
                separators: "",
                keep: "",
            };
            let result = macro_case_with_options("ABC_DEF_GHI", &opts);
            assert_eq!(result, "ABC_DEF_GHI");
        }

        #[test]
        fn convert_cobol_case() {
            let opts = Options {
                separate_before_non_alphabets: false,
                separate_after_non_alphabets: true,
                separators: "",
                keep: "",
            };
            let result = macro_case_with_options("ABC-DEF-GHI", &opts);
            assert_eq!(result, "ABC_DEF_GHI");
        }

        #[test]
        fn convert_with_digits() {
            let opts = Options {
                separate_before_non_alphabets: false,
                separate_after_non_alphabets: true,
                separators: "",
                keep: "",
            };
            let result = macro_case_with_options("abc123-456defG89HIJklMN12", &opts);
            assert_eq!(result, "ABC123_456_DEF_G89_HI_JKL_MN12");
        }

        #[test]
        fn convert_with_symbols_as_separators() {
            let opts = Options {
                separate_before_non_alphabets: false,
                separate_after_non_alphabets: true,
                separators: "",
                keep: "",
            };
            let result = macro_case_with_options(":.abc~!@def#$ghi%&jk(lm)no/?", &opts);
            assert_eq!(result, "ABC_DEF_GHI_JK_LM_NO");
        }

        #[test]
        fn convert_when_starting_with_digit() {
            let opts = Options {
                separate_before_non_alphabets: false,
                separate_after_non_alphabets: true,
                separators: "",
                keep: "",
            };
            let result = macro_case_with_options("123abc456def", &opts);
            assert_eq!(result, "123_ABC456_DEF");

            let result = macro_case_with_options("123ABC456DEF", &opts);
            assert_eq!(result, "123_ABC456_DEF");

            let result = macro_case_with_options("123Abc456Def", &opts);
            assert_eq!(result, "123_ABC456_DEF");
        }

        #[test]
        fn convert_empty_string() {
            let opts = Options {
                separate_before_non_alphabets: false,
                separate_after_non_alphabets: true,
                separators: "",
                keep: "",
            };
            let result = macro_case_with_options("", &opts);
            assert_eq!(result, "");
        }
    }

    mod non_alphabets_as_a_word {
        use super::*;

        #[test]
        fn convert_camel_case() {
            let opts = Options {
                separate_before_non_alphabets: true,
                separate_after_non_alphabets: true,
                separators: "",
                keep: "",
            };
            let result = macro_case_with_options("abcDefGHIjk", &opts);
            assert_eq!(result, "ABC_DEF_GH_IJK");
        }

        #[test]
        fn convert_pascal_case() {
            let opts = Options {
                separate_before_non_alphabets: true,
                separate_after_non_alphabets: true,
                separators: "",
                keep: "",
            };
            let result = macro_case_with_options("AbcDefGHIjk", &opts);
            assert_eq!(result, "ABC_DEF_GH_IJK");
        }

        #[test]
        fn convert_snake_case() {
            let opts = Options {
                separate_before_non_alphabets: true,
                separate_after_non_alphabets: true,
                separators: "",
                keep: "",
            };
            let result = macro_case_with_options("abc_def_ghi", &opts);
            assert_eq!(result, "ABC_DEF_GHI");
        }

        #[test]
        fn convert_kebab_case() {
            let opts = Options {
                separate_before_non_alphabets: true,
                separate_after_non_alphabets: true,
                separators: "",
                keep: "",
            };
            let result = macro_case_with_options("abc-def-ghi", &opts);
            assert_eq!(result, "ABC_DEF_GHI");
        }

        #[test]
        fn convert_train_case() {
            let opts = Options {
                separate_before_non_alphabets: true,
                separate_after_non_alphabets: true,
                separators: "",
                keep: "",
            };
            let result = macro_case_with_options("Abc-Def-Ghi", &opts);
            assert_eq!(result, "ABC_DEF_GHI");
        }

        #[test]
        fn convert_macro_case() {
            let opts = Options {
                separate_before_non_alphabets: true,
                separate_after_non_alphabets: true,
                separators: "",
                keep: "",
            };
            let result = macro_case_with_options("ABC_DEF_GHI", &opts);
            assert_eq!(result, "ABC_DEF_GHI");
        }

        #[test]
        fn convert_cobol_case() {
            let opts = Options {
                separate_before_non_alphabets: true,
                separate_after_non_alphabets: true,
                separators: "",
                keep: "",
            };
            let result = macro_case_with_options("ABC-DEF-GHI", &opts);
            assert_eq!(result, "ABC_DEF_GHI");
        }

        #[test]
        fn convert_with_digits() {
            let opts = Options {
                separate_before_non_alphabets: true,
                separate_after_non_alphabets: true,
                separators: "",
                keep: "",
            };
            let result = macro_case_with_options("abc123-456defG89HIJklMN12", &opts);
            assert_eq!(result, "ABC_123_456_DEF_G_89_HI_JKL_MN_12");
        }

        #[test]
        fn convert_with_symbols_as_separators() {
            let opts = Options {
                separate_before_non_alphabets: true,
                separate_after_non_alphabets: true,
                separators: "",
                keep: "",
            };
            let result = macro_case_with_options(":.abc~!@def#$ghi%&jk(lm)no/?", &opts);
            assert_eq!(result, "ABC_DEF_GHI_JK_LM_NO");
        }

        #[test]
        fn convert_when_starting_with_digit() {
            let opts = Options {
                separate_before_non_alphabets: true,
                separate_after_non_alphabets: true,
                separators: "",
                keep: "",
            };
            let result = macro_case_with_options("123abc456def", &opts);
            assert_eq!(result, "123_ABC_456_DEF");

            let result = macro_case_with_options("123ABC456DEF", &opts);
            assert_eq!(result, "123_ABC_456_DEF");

            let result = macro_case_with_options("123Abc456Def", &opts);
            assert_eq!(result, "123_ABC_456_DEF");
        }

        #[test]
        fn convert_empty_string() {
            let opts = Options {
                separate_before_non_alphabets: true,
                separate_after_non_alphabets: true,
                separators: "",
                keep: "",
            };
            let result = macro_case_with_options("", &opts);
            assert_eq!(result, "");
        }
    }

    mod non_alphabets_as_part_of_a_word {
        use super::*;

        #[test]
        fn convert_camel_case() {
            let opts = Options {
                separate_before_non_alphabets: false,
                separate_after_non_alphabets: false,
                separators: "",
                keep: "",
            };
            let result = macro_case_with_options("abcDefGHIjk", &opts);
            assert_eq!(result, "ABC_DEF_GH_IJK");
        }

        #[test]
        fn convert_pascal_case() {
            let opts = Options {
                separate_before_non_alphabets: false,
                separate_after_non_alphabets: false,
                separators: "",
                keep: "",
            };
            let result = macro_case_with_options("AbcDefGHIjk", &opts);
            assert_eq!(result, "ABC_DEF_GH_IJK");
        }

        #[test]
        fn convert_snake_case() {
            let opts = Options {
                separate_before_non_alphabets: false,
                separate_after_non_alphabets: false,
                separators: "",
                keep: "",
            };
            let result = macro_case_with_options("abc_def_ghi", &opts);
            assert_eq!(result, "ABC_DEF_GHI");
        }

        #[test]
        fn convert_kebab_case() {
            let opts = Options {
                separate_before_non_alphabets: false,
                separate_after_non_alphabets: false,
                separators: "",
                keep: "",
            };
            let result = macro_case_with_options("abc-def-ghi", &opts);
            assert_eq!(result, "ABC_DEF_GHI");
        }

        #[test]
        fn convert_train_case() {
            let opts = Options {
                separate_before_non_alphabets: false,
                separate_after_non_alphabets: false,
                separators: "",
                keep: "",
            };
            let result = macro_case_with_options("Abc-Def-Ghi", &opts);
            assert_eq!(result, "ABC_DEF_GHI");
        }

        #[test]
        fn convert_macro_case() {
            let opts = Options {
                separate_before_non_alphabets: false,
                separate_after_non_alphabets: false,
                separators: "",
                keep: "",
            };
            let result = macro_case_with_options("ABC_DEF_GHI", &opts);
            assert_eq!(result, "ABC_DEF_GHI");
        }

        #[test]
        fn convert_cobol_case() {
            let opts = Options {
                separate_before_non_alphabets: false,
                separate_after_non_alphabets: false,
                separators: "",
                keep: "",
            };
            let result = macro_case_with_options("ABC-DEF-GHI", &opts);
            assert_eq!(result, "ABC_DEF_GHI");
        }

        #[test]
        fn convert_with_digits() {
            let opts = Options {
                separate_before_non_alphabets: false,
                separate_after_non_alphabets: false,
                separators: "",
                keep: "",
            };
            let result = macro_case_with_options("abc123-456defG89HIJklMN12", &opts);
            assert_eq!(result, "ABC123_456DEF_G89HI_JKL_MN12");
        }

        #[test]
        fn convert_with_symbols_as_separators() {
            let opts = Options {
                separate_before_non_alphabets: false,
                separate_after_non_alphabets: false,
                separators: "",
                keep: "",
            };
            let result = macro_case_with_options(":.abc~!@def#$ghi%&jk(lm)no/?", &opts);
            assert_eq!(result, "ABC_DEF_GHI_JK_LM_NO");
        }

        #[test]
        fn convert_when_starting_with_digit() {
            let opts = Options {
                separate_before_non_alphabets: false,
                separate_after_non_alphabets: false,
                separators: "",
                keep: "",
            };
            let result = macro_case_with_options("123abc456def", &opts);
            assert_eq!(result, "123ABC456DEF");

            let result = macro_case_with_options("123ABC456DEF", &opts);
            assert_eq!(result, "123ABC456DEF");

            let result = macro_case_with_options("123Abc456Def", &opts);
            assert_eq!(result, "123_ABC456_DEF");
        }

        #[test]
        fn convert_empty_string() {
            let opts = Options {
                separate_before_non_alphabets: false,
                separate_after_non_alphabets: false,
                separators: "",
                keep: "",
            };
            let result = macro_case_with_options("", &opts);
            assert_eq!(result, "");
        }
    }

    mod non_alphabets_as_head_of_a_word_with_separators {
        use super::*;

        #[test]
        fn convert_camel_case() {
            let opts = Options {
                separate_before_non_alphabets: true,
                separate_after_non_alphabets: false,
                separators: "-_",
                keep: "",
            };
            let result = macro_case_with_options("abcDefGHIjk", &opts);
            assert_eq!(result, "ABC_DEF_GH_IJK");
        }

        #[test]
        fn convert_pascal_case() {
            let opts = Options {
                separate_before_non_alphabets: true,
                separate_after_non_alphabets: false,
                separators: "-_",
                keep: "",
            };
            let result = macro_case_with_options("AbcDefGHIjk", &opts);
            assert_eq!(result, "ABC_DEF_GH_IJK");
        }

        #[test]
        fn convert_snake_case() {
            let mut opts = Options {
                separate_before_non_alphabets: true,
                separate_after_non_alphabets: false,
                separators: "_",
                keep: "",
            };
            let result = macro_case_with_options("abc_def_ghi", &opts);
            assert_eq!(result, "ABC_DEF_GHI");

            opts.separators = "-";
            let result = macro_case_with_options("abc_def_ghi", &opts);
            assert_eq!(result, "ABC__DEF__GHI");
        }

        #[test]
        fn convert_kebab_case() {
            let mut opts = Options {
                separate_before_non_alphabets: true,
                separate_after_non_alphabets: false,
                separators: "-",
                keep: "",
            };
            let result = macro_case_with_options("abc-def-ghi", &opts);
            assert_eq!(result, "ABC_DEF_GHI");

            opts.separators = "_";
            let result = macro_case_with_options("abc-def-ghi", &opts);
            assert_eq!(result, "ABC_-DEF_-GHI");
        }

        #[test]
        fn convert_train_case() {
            let mut opts = Options {
                separate_before_non_alphabets: true,
                separate_after_non_alphabets: false,
                separators: "-",
                keep: "",
            };
            let result = macro_case_with_options("Abc-Def-Ghi", &opts);
            assert_eq!(result, "ABC_DEF_GHI");

            opts.separators = "_";
            let result = macro_case_with_options("Abc-Def-Ghi", &opts);
            assert_eq!(result, "ABC_-_DEF_-_GHI");
        }

        #[test]
        fn convert_macro_case() {
            let mut opts = Options {
                separate_before_non_alphabets: true,
                separate_after_non_alphabets: false,
                separators: "_",
                keep: "",
            };
            let result = macro_case_with_options("ABC_DEF_GHI", &opts);
            assert_eq!(result, "ABC_DEF_GHI");

            opts.separators = "-";
            let result = macro_case_with_options("ABC_DEF_GHI", &opts);
            assert_eq!(result, "ABC__DEF__GHI");
        }

        #[test]
        fn convert_cobol_case() {
            let mut opts = Options {
                separate_before_non_alphabets: true,
                separate_after_non_alphabets: false,
                separators: "-",
                keep: "",
            };
            let result = macro_case_with_options("ABC-DEF-GHI", &opts);
            assert_eq!(result, "ABC_DEF_GHI");

            opts.separators = "_";
            let result = macro_case_with_options("ABC-DEF-GHI", &opts);
            assert_eq!(result, "ABC_-DEF_-GHI");
        }

        #[test]
        fn convert_with_keeping_digits() {
            let mut opts = Options {
                separate_before_non_alphabets: true,
                separate_after_non_alphabets: false,
                separators: "-",
                keep: "",
            };
            let result = macro_case_with_options("abc123-456defG89HIJklMN12", &opts);
            assert_eq!(result, "ABC_123_456DEF_G_89HI_JKL_MN_12");

            opts.separators = "_";
            let result = macro_case_with_options("abc123-456defG89HIJklMN12", &opts);
            assert_eq!(result, "ABC_123-456DEF_G_89HI_JKL_MN_12");
        }

        #[test]
        fn convert_with_symbols_as_separators() {
            let opts = Options {
                separate_before_non_alphabets: true,
                separate_after_non_alphabets: false,
                separators: ":@$&()/",
                keep: "",
            };
            let result = macro_case_with_options(":.abc~!@def#$ghi%&jk(lm)no/?", &opts);
            assert_eq!(result, ".ABC_~!_DEF_#_GHI_%_JK_LM_NO_?");
        }

        #[test]
        fn convert_when_starting_with_digit() {
            let opts = Options {
                separate_before_non_alphabets: true,
                separate_after_non_alphabets: false,
                separators: "-_",
                keep: "",
            };
            let result = macro_case_with_options("123abc456def", &opts);
            assert_eq!(result, "123ABC_456DEF");

            let result = macro_case_with_options("123ABC456DEF", &opts);
            assert_eq!(result, "123ABC_456DEF");

            let result = macro_case_with_options("123Abc456Def", &opts);
            assert_eq!(result, "123_ABC_456_DEF");
        }

        #[test]
        fn convert_empty_string() {
            let opts = Options {
                separate_before_non_alphabets: true,
                separate_after_non_alphabets: false,
                separators: "-_",
                keep: "",
            };
            let result = macro_case_with_options("", &opts);
            assert_eq!(result, "");
        }
    }

    mod non_alphabets_as_tail_of_a_word_with_separators {
        use super::*;

        #[test]
        fn convert_camel_case() {
            let opts = Options {
                separate_before_non_alphabets: false,
                separate_after_non_alphabets: true,
                separators: "-_",
                keep: "",
            };
            let result = macro_case_with_options("abcDefGHIjk", &opts);
            assert_eq!(result, "ABC_DEF_GH_IJK");
        }

        #[test]
        fn convert_pascal_case() {
            let opts = Options {
                separate_before_non_alphabets: false,
                separate_after_non_alphabets: true,
                separators: "-_",
                keep: "",
            };
            let result = macro_case_with_options("AbcDefGHIjk", &opts);
            assert_eq!(result, "ABC_DEF_GH_IJK");
        }

        #[test]
        fn convert_snake_case() {
            let mut opts = Options {
                separate_before_non_alphabets: false,
                separate_after_non_alphabets: true,
                separators: "_",
                keep: "",
            };
            let result = macro_case_with_options("abc_def_ghi", &opts);
            assert_eq!(result, "ABC_DEF_GHI");

            opts.separators = "-";
            let result = macro_case_with_options("abc_def_ghi", &opts);
            assert_eq!(result, "ABC__DEF__GHI");
        }

        #[test]
        fn convert_kebab_case() {
            let mut opts = Options {
                separate_before_non_alphabets: false,
                separate_after_non_alphabets: true,
                separators: "-",
                keep: "",
            };
            let result = macro_case_with_options("abc-def-ghi", &opts);
            assert_eq!(result, "ABC_DEF_GHI");

            opts.separators = "_";
            let result = macro_case_with_options("abc-def-ghi", &opts);
            assert_eq!(result, "ABC-_DEF-_GHI");
        }

        #[test]
        fn convert_train_case() {
            let mut opts = Options {
                separate_before_non_alphabets: false,
                separate_after_non_alphabets: true,
                separators: "-",
                keep: "",
            };
            let result = macro_case_with_options("Abc-Def-Ghi", &opts);
            assert_eq!(result, "ABC_DEF_GHI");

            opts.separators = "_";
            let result = macro_case_with_options("Abc-Def-Ghi", &opts);
            assert_eq!(result, "ABC-_DEF-_GHI");
        }

        #[test]
        fn convert_macro_case() {
            let mut opts = Options {
                separate_before_non_alphabets: false,
                separate_after_non_alphabets: true,
                separators: "_",
                keep: "",
            };
            let result = macro_case_with_options("ABC_DEF_GHI", &opts);
            assert_eq!(result, "ABC_DEF_GHI");

            opts.separators = "-";
            let result = macro_case_with_options("ABC_DEF_GHI", &opts);
            assert_eq!(result, "ABC__DEF__GHI");
        }

        #[test]
        fn convert_cobol_case() {
            let mut opts = Options {
                separate_before_non_alphabets: false,
                separate_after_non_alphabets: true,
                separators: "-",
                keep: "",
            };
            let result = macro_case_with_options("ABC-DEF-GHI", &opts);
            assert_eq!(result, "ABC_DEF_GHI");

            opts.separators = "_";
            let result = macro_case_with_options("ABC-DEF-GHI", &opts);
            assert_eq!(result, "ABC-_DEF-_GHI");
        }

        #[test]
        fn convert_with_keeping_digits() {
            let mut opts = Options {
                separate_before_non_alphabets: false,
                separate_after_non_alphabets: true,
                separators: "-",
                keep: "",
            };
            let result = macro_case_with_options("abc123-456defG89HIJklMN12", &opts);
            assert_eq!(result, "ABC123_456_DEF_G89_HI_JKL_MN12");

            opts.separators = "_";
            let result = macro_case_with_options("abc123-456defG89HIJklMN12", &opts);
            assert_eq!(result, "ABC123-456_DEF_G89_HI_JKL_MN12");
        }

        #[test]
        fn convert_with_symbols_as_separators() {
            let opts = Options {
                separate_before_non_alphabets: false,
                separate_after_non_alphabets: true,
                separators: ":@$&()/",
                keep: "",
            };
            let result = macro_case_with_options(":.abc~!@def#$ghi%&jk(lm)no/?", &opts);
            assert_eq!(result, "._ABC~!_DEF#_GHI%_JK_LM_NO_?");
        }

        #[test]
        fn convert_when_starting_with_digit() {
            let opts = Options {
                separate_before_non_alphabets: false,
                separate_after_non_alphabets: true,
                separators: "-_",
                keep: "",
            };
            let result = macro_case_with_options("123abc456def", &opts);
            assert_eq!(result, "123_ABC456_DEF");

            let result = macro_case_with_options("123ABC456DEF", &opts);
            assert_eq!(result, "123_ABC456_DEF");

            let result = macro_case_with_options("123Abc456Def", &opts);
            assert_eq!(result, "123_ABC456_DEF");
        }

        #[test]
        fn convert_empty_string() {
            let opts = Options {
                separate_before_non_alphabets: false,
                separate_after_non_alphabets: true,
                separators: "-_",
                keep: "",
            };
            let result = macro_case_with_options("", &opts);
            assert_eq!(result, "");
        }
    }

    mod non_alphabets_as_a_word_with_separators {
        use super::*;

        #[test]
        fn convert_camel_case() {
            let opts = Options {
                separate_before_non_alphabets: true,
                separate_after_non_alphabets: true,
                separators: "-_",
                keep: "",
            };
            let result = macro_case_with_options("abcDefGHIjk", &opts);
            assert_eq!(result, "ABC_DEF_GH_IJK");
        }

        #[test]
        fn convert_pascal_case() {
            let opts = Options {
                separate_before_non_alphabets: true,
                separate_after_non_alphabets: true,
                separators: "-_",
                keep: "",
            };
            let result = macro_case_with_options("AbcDefGHIjk", &opts);
            assert_eq!(result, "ABC_DEF_GH_IJK");
        }

        #[test]
        fn convert_snake_case() {
            let mut opts = Options {
                separate_before_non_alphabets: true,
                separate_after_non_alphabets: true,
                separators: "_",
                keep: "",
            };
            let result = macro_case_with_options("abc_def_ghi", &opts);
            assert_eq!(result, "ABC_DEF_GHI");

            opts.separators = "-";
            let result = macro_case_with_options("abc_def_ghi", &opts);
            assert_eq!(result, "ABC___DEF___GHI");
        }

        #[test]
        fn convert_kebab_case() {
            let mut opts = Options {
                separate_before_non_alphabets: true,
                separate_after_non_alphabets: true,
                separators: "-",
                keep: "",
            };
            let result = macro_case_with_options("abc-def-ghi", &opts);
            assert_eq!(result, "ABC_DEF_GHI");

            opts.separators = "_";
            let result = macro_case_with_options("abc-def-ghi", &opts);
            assert_eq!(result, "ABC_-_DEF_-_GHI");
        }

        #[test]
        fn convert_train_case() {
            let mut opts = Options {
                separate_before_non_alphabets: true,
                separate_after_non_alphabets: true,
                separators: "-",
                keep: "",
            };
            let result = macro_case_with_options("Abc-Def-Ghi", &opts);
            assert_eq!(result, "ABC_DEF_GHI");

            opts.separators = "_";
            let result = macro_case_with_options("Abc-Def-Ghi", &opts);
            assert_eq!(result, "ABC_-_DEF_-_GHI");
        }

        #[test]
        fn convert_macro_case() {
            let mut opts = Options {
                separate_before_non_alphabets: true,
                separate_after_non_alphabets: true,
                separators: "_",
                keep: "",
            };
            let result = macro_case_with_options("ABC_DEF_GHI", &opts);
            assert_eq!(result, "ABC_DEF_GHI");

            opts.separators = "-";
            let result = macro_case_with_options("ABC_DEF_GHI", &opts);
            assert_eq!(result, "ABC___DEF___GHI");
        }

        #[test]
        fn convert_cobol_case() {
            let mut opts = Options {
                separate_before_non_alphabets: true,
                separate_after_non_alphabets: true,
                separators: "-",
                keep: "",
            };
            let result = macro_case_with_options("ABC-DEF-GHI", &opts);
            assert_eq!(result, "ABC_DEF_GHI");

            opts.separators = "_";
            let result = macro_case_with_options("ABC-DEF-GHI", &opts);
            assert_eq!(result, "ABC_-_DEF_-_GHI");
        }

        #[test]
        fn convert_with_keeping_digits() {
            let mut opts = Options {
                separate_before_non_alphabets: true,
                separate_after_non_alphabets: true,
                separators: "-",
                keep: "",
            };
            let result = macro_case_with_options("abc123-456defG89HIJklMN12", &opts);
            assert_eq!(result, "ABC_123_456_DEF_G_89_HI_JKL_MN_12");

            opts.separators = "_";
            let result = macro_case_with_options("abc123-456defG89HIJklMN12", &opts);
            assert_eq!(result, "ABC_123-456_DEF_G_89_HI_JKL_MN_12");
        }

        #[test]
        fn convert_with_symbols_as_separators() {
            let opts = Options {
                separate_before_non_alphabets: true,
                separate_after_non_alphabets: true,
                separators: ":@$&()/",
                keep: "",
            };
            let result = macro_case_with_options(":.abc~!@def#$ghi%&jk(lm)no/?", &opts);
            assert_eq!(result, "._ABC_~!_DEF_#_GHI_%_JK_LM_NO_?");
        }

        #[test]
        fn convert_when_starting_with_digit() {
            let opts = Options {
                separate_before_non_alphabets: true,
                separate_after_non_alphabets: true,
                separators: "-_",
                keep: "",
            };
            let result = macro_case_with_options("123abc456def", &opts);
            assert_eq!(result, "123_ABC_456_DEF");

            let result = macro_case_with_options("123ABC456DEF", &opts);
            assert_eq!(result, "123_ABC_456_DEF");

            let result = macro_case_with_options("123Abc456Def", &opts);
            assert_eq!(result, "123_ABC_456_DEF");
        }

        #[test]
        fn convert_empty_string() {
            let opts = Options {
                separate_before_non_alphabets: true,
                separate_after_non_alphabets: true,
                separators: "-_",
                keep: "",
            };
            let result = macro_case_with_options("", &opts);
            assert_eq!(result, "");
        }
    }

    mod non_alphabets_as_part_of_a_word_with_separators {
        use super::*;

        #[test]
        fn convert_camel_case() {
            let opts = Options {
                separate_before_non_alphabets: false,
                separate_after_non_alphabets: false,
                separators: "-_",
                keep: "",
            };
            let result = macro_case_with_options("abcDefGHIjk", &opts);
            assert_eq!(result, "ABC_DEF_GH_IJK");
        }

        #[test]
        fn convert_pascal_case() {
            let opts = Options {
                separate_before_non_alphabets: false,
                separate_after_non_alphabets: false,
                separators: "-_",
                keep: "",
            };
            let result = macro_case_with_options("AbcDefGHIjk", &opts);
            assert_eq!(result, "ABC_DEF_GH_IJK");
        }

        #[test]
        fn convert_snake_case() {
            let mut opts = Options {
                separate_before_non_alphabets: false,
                separate_after_non_alphabets: false,
                separators: "_",
                keep: "",
            };
            let result = macro_case_with_options("abc_def_ghi", &opts);
            assert_eq!(result, "ABC_DEF_GHI");

            opts.separators = "-";
            let result = macro_case_with_options("abc_def_ghi", &opts);
            assert_eq!(result, "ABC_DEF_GHI");
        }

        #[test]
        fn convert_kebab_case() {
            let mut opts = Options {
                separate_before_non_alphabets: false,
                separate_after_non_alphabets: false,
                separators: "-",
                keep: "",
            };
            let result = macro_case_with_options("abc-def-ghi", &opts);
            assert_eq!(result, "ABC_DEF_GHI");

            opts.separators = "_";
            let result = macro_case_with_options("abc-def-ghi", &opts);
            assert_eq!(result, "ABC-DEF-GHI");
        }

        #[test]
        fn convert_train_case() {
            let mut opts = Options {
                separate_before_non_alphabets: false,
                separate_after_non_alphabets: false,
                separators: "-",
                keep: "",
            };
            let result = macro_case_with_options("Abc-Def-Ghi", &opts);
            assert_eq!(result, "ABC_DEF_GHI");

            opts.separators = "_";
            let result = macro_case_with_options("Abc-Def-Ghi", &opts);
            assert_eq!(result, "ABC-_DEF-_GHI");
        }

        #[test]
        fn convert_macro_case() {
            let mut opts = Options {
                separate_before_non_alphabets: false,
                separate_after_non_alphabets: false,
                separators: "_",
                keep: "",
            };
            let result = macro_case_with_options("ABC_DEF_GHI", &opts);
            assert_eq!(result, "ABC_DEF_GHI");

            opts.separators = "-";
            let result = macro_case_with_options("ABC_DEF_GHI", &opts);
            assert_eq!(result, "ABC_DEF_GHI");
        }

        #[test]
        fn convert_cobol_case() {
            let mut opts = Options {
                separate_before_non_alphabets: false,
                separate_after_non_alphabets: false,
                separators: "-",
                keep: "",
            };
            let result = macro_case_with_options("ABC-DEF-GHI", &opts);
            assert_eq!(result, "ABC_DEF_GHI");

            opts.separators = "_";
            let result = macro_case_with_options("ABC-DEF-GHI", &opts);
            assert_eq!(result, "ABC-DEF-GHI");
        }

        #[test]
        fn convert_with_keeping_digits() {
            let mut opts = Options {
                separate_before_non_alphabets: false,
                separate_after_non_alphabets: false,
                separators: "-",
                keep: "",
            };
            let result = macro_case_with_options("abc123-456defG89HIJklMN12", &opts);
            assert_eq!(result, "ABC123_456DEF_G89HI_JKL_MN12");

            opts.separators = "_";
            let result = macro_case_with_options("abc123-456defG89HIJklMN12", &opts);
            assert_eq!(result, "ABC123-456DEF_G89HI_JKL_MN12");
        }

        #[test]
        fn convert_with_symbols_as_separators() {
            let opts = Options {
                separate_before_non_alphabets: false,
                separate_after_non_alphabets: false,
                separators: ":@$&()/",
                keep: "",
            };
            let result = macro_case_with_options(":.abc~!@def#$ghi%&jk(lm)no/?", &opts);
            assert_eq!(result, ".ABC~!_DEF#_GHI%_JK_LM_NO_?");
        }

        #[test]
        fn convert_when_starting_with_digit() {
            let opts = Options {
                separate_before_non_alphabets: false,
                separate_after_non_alphabets: false,
                separators: "-_",
                keep: "",
            };
            let result = macro_case_with_options("123abc456def", &opts);
            assert_eq!(result, "123ABC456DEF");

            let result = macro_case_with_options("123ABC456DEF", &opts);
            assert_eq!(result, "123ABC456DEF");

            let result = macro_case_with_options("123Abc456Def", &opts);
            assert_eq!(result, "123_ABC456_DEF");
        }

        #[test]
        fn convert_empty_string() {
            let opts = Options {
                separate_before_non_alphabets: false,
                separate_after_non_alphabets: false,
                separators: "-_",
                keep: "",
            };
            let result = macro_case_with_options("", &opts);
            assert_eq!(result, "");
        }
    }

    mod non_alphabets_as_head_of_a_word_with_kept_characters {
        use super::*;

        #[test]
        fn convert_camel_case() {
            let opts = Options {
                separate_before_non_alphabets: true,
                separate_after_non_alphabets: false,
                separators: "",
                keep: "-_",
            };
            let result = macro_case_with_options("abcDefGHIjk", &opts);
            assert_eq!(result, "ABC_DEF_GH_IJK");
        }

        #[test]
        fn convert_pascal_case() {
            let opts = Options {
                separate_before_non_alphabets: true,
                separate_after_non_alphabets: false,
                separators: "",
                keep: "-_",
            };
            let result = macro_case_with_options("AbcDefGHIjk", &opts);
            assert_eq!(result, "ABC_DEF_GH_IJK");
        }

        #[test]
        fn convert_snake_case() {
            let mut opts = Options {
                separate_before_non_alphabets: true,
                separate_after_non_alphabets: false,
                separators: "",
                keep: "_",
            };
            let result = macro_case_with_options("abc_def_ghi", &opts);
            assert_eq!(result, "ABC__DEF__GHI");

            opts.keep = "-";
            let result = macro_case_with_options("abc_def_ghi", &opts);
            assert_eq!(result, "ABC_DEF_GHI");
        }

        #[test]
        fn convert_kebab_case() {
            let mut opts = Options {
                separate_before_non_alphabets: true,
                separate_after_non_alphabets: false,
                separators: "",
                keep: "_",
            };
            let result = macro_case_with_options("abc-def-ghi", &opts);
            assert_eq!(result, "ABC_DEF_GHI");

            opts.keep = "-";
            let result = macro_case_with_options("abc-def-ghi", &opts);
            assert_eq!(result, "ABC_-DEF_-GHI");
        }

        #[test]
        fn convert_train_case() {
            let mut opts = Options {
                separate_before_non_alphabets: true,
                separate_after_non_alphabets: false,
                separators: "",
                keep: "_",
            };
            let result = macro_case_with_options("Abc-Def-Ghi", &opts);
            assert_eq!(result, "ABC_DEF_GHI");

            opts.keep = "-";
            let result = macro_case_with_options("Abc-Def-Ghi", &opts);
            assert_eq!(result, "ABC_-_DEF_-_GHI");
        }

        #[test]
        fn convert_macro_case() {
            let mut opts = Options {
                separate_before_non_alphabets: true,
                separate_after_non_alphabets: false,
                separators: "",
                keep: "-",
            };
            let result = macro_case_with_options("ABC_DEF_GHI", &opts);
            assert_eq!(result, "ABC_DEF_GHI");

            opts.keep = "_";
            let result = macro_case_with_options("ABC_DEF_GHI", &opts);
            assert_eq!(result, "ABC__DEF__GHI");
        }

        #[test]
        fn convert_cobol_case() {
            let mut opts = Options {
                separate_before_non_alphabets: true,
                separate_after_non_alphabets: false,
                separators: "",
                keep: "_",
            };
            let result = macro_case_with_options("ABC-DEF-GHI", &opts);
            assert_eq!(result, "ABC_DEF_GHI");

            opts.keep = "-";
            let result = macro_case_with_options("ABC-DEF-GHI", &opts);
            assert_eq!(result, "ABC_-DEF_-GHI");
        }

        #[test]
        fn convert_with_keeping_digits() {
            let mut opts = Options {
                separate_before_non_alphabets: true,
                separate_after_non_alphabets: false,
                separators: "",
                keep: "_",
            };
            let result = macro_case_with_options("abc123-456defG89HIJklMN12", &opts);
            assert_eq!(result, "ABC_123_456DEF_G_89HI_JKL_MN_12");

            opts.keep = "-";
            let result = macro_case_with_options("abc123-456defG89HIJklMN12", &opts);
            assert_eq!(result, "ABC_123-456DEF_G_89HI_JKL_MN_12");
        }

        #[test]
        fn convert_with_symbols_as_separators() {
            let opts = Options {
                separate_before_non_alphabets: true,
                separate_after_non_alphabets: false,
                separators: "",
                keep: ".~!#%?",
            };
            let result = macro_case_with_options(":.abc~!@def#$ghi%&jk(lm)no/?", &opts);
            assert_eq!(result, ".ABC_~!_DEF_#_GHI_%_JK_LM_NO_?");
        }

        #[test]
        fn convert_when_starting_with_digit() {
            let opts = Options {
                separate_before_non_alphabets: true,
                separate_after_non_alphabets: false,
                separators: "",
                keep: "-_",
            };
            let result = macro_case_with_options("123abc456def", &opts);
            assert_eq!(result, "123ABC_456DEF");

            let result = macro_case_with_options("123ABC456DEF", &opts);
            assert_eq!(result, "123ABC_456DEF");

            let result = macro_case_with_options("123Abc456Def", &opts);
            assert_eq!(result, "123_ABC_456_DEF");
        }

        #[test]
        fn convert_empty_string() {
            let opts = Options {
                separate_before_non_alphabets: true,
                separate_after_non_alphabets: false,
                separators: "",
                keep: "-_",
            };
            let result = macro_case_with_options("", &opts);
            assert_eq!(result, "");
        }
    }

    mod non_alphabets_as_tail_of_a_word_with_kept_characters {
        use super::*;

        #[test]
        fn convert_camel_case() {
            let opts = Options {
                separate_before_non_alphabets: false,
                separate_after_non_alphabets: true,
                separators: "",
                keep: "-_",
            };
            let result = macro_case_with_options("abcDefGHIjk", &opts);
            assert_eq!(result, "ABC_DEF_GH_IJK");
        }

        #[test]
        fn convert_pascal_case() {
            let opts = Options {
                separate_before_non_alphabets: false,
                separate_after_non_alphabets: true,
                separators: "",
                keep: "-_",
            };
            let result = macro_case_with_options("AbcDefGHIjk", &opts);
            assert_eq!(result, "ABC_DEF_GH_IJK");
        }

        #[test]
        fn convert_snake_case() {
            let mut opts = Options {
                separate_before_non_alphabets: false,
                separate_after_non_alphabets: true,
                separators: "",
                keep: "-",
            };
            let result = macro_case_with_options("abc_def_ghi", &opts);
            assert_eq!(result, "ABC_DEF_GHI");

            opts.keep = "_";
            let result = macro_case_with_options("abc_def_ghi", &opts);
            assert_eq!(result, "ABC__DEF__GHI");
        }

        #[test]
        fn convert_kebab_case() {
            let mut opts = Options {
                separate_before_non_alphabets: false,
                separate_after_non_alphabets: true,
                separators: "",
                keep: "_",
            };
            let result = macro_case_with_options("abc-def-ghi", &opts);
            assert_eq!(result, "ABC_DEF_GHI");

            opts.keep = "-";
            let result = macro_case_with_options("abc-def-ghi", &opts);
            assert_eq!(result, "ABC-_DEF-_GHI");
        }

        #[test]
        fn convert_train_case() {
            let mut opts = Options {
                separate_before_non_alphabets: false,
                separate_after_non_alphabets: true,
                separators: "",
                keep: "_",
            };
            let result = macro_case_with_options("Abc-Def-Ghi", &opts);
            assert_eq!(result, "ABC_DEF_GHI");

            opts.keep = "-";
            let result = macro_case_with_options("Abc-Def-Ghi", &opts);
            assert_eq!(result, "ABC-_DEF-_GHI");
        }

        #[test]
        fn convert_macro_case() {
            let mut opts = Options {
                separate_before_non_alphabets: false,
                separate_after_non_alphabets: true,
                separators: "",
                keep: "-",
            };
            let result = macro_case_with_options("ABC_DEF_GHI", &opts);
            assert_eq!(result, "ABC_DEF_GHI");

            opts.keep = "_";
            let result = macro_case_with_options("ABC_DEF_GHI", &opts);
            assert_eq!(result, "ABC__DEF__GHI");
        }

        #[test]
        fn convert_cobol_case() {
            let mut opts = Options {
                separate_before_non_alphabets: false,
                separate_after_non_alphabets: true,
                separators: "",
                keep: "_",
            };
            let result = macro_case_with_options("ABC-DEF-GHI", &opts);
            assert_eq!(result, "ABC_DEF_GHI");

            opts.keep = "-";
            let result = macro_case_with_options("ABC-DEF-GHI", &opts);
            assert_eq!(result, "ABC-_DEF-_GHI");
        }

        #[test]
        fn convert_with_keeping_digits() {
            let mut opts = Options {
                separate_before_non_alphabets: false,
                separate_after_non_alphabets: true,
                separators: "",
                keep: "_",
            };
            let result = macro_case_with_options("abc123-456defG89HIJklMN12", &opts);
            assert_eq!(result, "ABC123_456_DEF_G89_HI_JKL_MN12");

            opts.keep = "-";
            let result = macro_case_with_options("abc123-456defG89HIJklMN12", &opts);
            assert_eq!(result, "ABC123-456_DEF_G89_HI_JKL_MN12");
        }

        #[test]
        fn convert_with_symbols_as_separators() {
            let opts = Options {
                separate_before_non_alphabets: false,
                separate_after_non_alphabets: true,
                separators: "",
                keep: ".~!#%?",
            };
            let result = macro_case_with_options(":.abc~!@def#$ghi%&jk(lm)no/?", &opts);
            assert_eq!(result, "._ABC~!_DEF#_GHI%_JK_LM_NO_?");
        }

        #[test]
        fn convert_when_starting_with_digit() {
            let opts = Options {
                separate_before_non_alphabets: false,
                separate_after_non_alphabets: true,
                separators: "",
                keep: "-_",
            };
            let result = macro_case_with_options("123abc456def", &opts);
            assert_eq!(result, "123_ABC456_DEF");

            let result = macro_case_with_options("123ABC456DEF", &opts);
            assert_eq!(result, "123_ABC456_DEF");

            let result = macro_case_with_options("123Abc456Def", &opts);
            assert_eq!(result, "123_ABC456_DEF");
        }

        #[test]
        fn convert_empty_string() {
            let opts = Options {
                separate_before_non_alphabets: false,
                separate_after_non_alphabets: true,
                separators: "",
                keep: "-_",
            };
            let result = macro_case_with_options("", &opts);
            assert_eq!(result, "");
        }
    }

    mod non_alphabets_as_a_word_with_kept_characters {
        use super::*;

        #[test]
        fn convert_camel_case() {
            let opts = Options {
                separate_before_non_alphabets: true,
                separate_after_non_alphabets: true,
                separators: "",
                keep: "-_",
            };
            let result = macro_case_with_options("abcDefGHIjk", &opts);
            assert_eq!(result, "ABC_DEF_GH_IJK");
        }

        #[test]
        fn convert_pascal_case() {
            let opts = Options {
                separate_before_non_alphabets: true,
                separate_after_non_alphabets: true,
                separators: "",
                keep: "-_",
            };
            let result = macro_case_with_options("AbcDefGHIjk", &opts);
            assert_eq!(result, "ABC_DEF_GH_IJK");
        }

        #[test]
        fn convert_snake_case() {
            let mut opts = Options {
                separate_before_non_alphabets: true,
                separate_after_non_alphabets: true,
                separators: "",
                keep: "-",
            };
            let result = macro_case_with_options("abc_def_ghi", &opts);
            assert_eq!(result, "ABC_DEF_GHI");

            opts.keep = "_";
            let result = macro_case_with_options("abc_def_ghi", &opts);
            assert_eq!(result, "ABC___DEF___GHI");
        }

        #[test]
        fn convert_kebab_case() {
            let mut opts = Options {
                separate_before_non_alphabets: true,
                separate_after_non_alphabets: true,
                separators: "",
                keep: "_",
            };
            let result = macro_case_with_options("abc-def-ghi", &opts);
            assert_eq!(result, "ABC_DEF_GHI");

            opts.keep = "-";
            let result = macro_case_with_options("abc-def-ghi", &opts);
            assert_eq!(result, "ABC_-_DEF_-_GHI");
        }

        #[test]
        fn convert_train_case() {
            let mut opts = Options {
                separate_before_non_alphabets: true,
                separate_after_non_alphabets: true,
                separators: "",
                keep: "_",
            };
            let result = macro_case_with_options("Abc-Def-Ghi", &opts);
            assert_eq!(result, "ABC_DEF_GHI");

            opts.keep = "-";
            let result = macro_case_with_options("Abc-Def-Ghi", &opts);
            assert_eq!(result, "ABC_-_DEF_-_GHI");
        }

        #[test]
        fn convert_macro_case() {
            let mut opts = Options {
                separate_before_non_alphabets: true,
                separate_after_non_alphabets: true,
                separators: "",
                keep: "-",
            };
            let result = macro_case_with_options("ABC_DEF_GHI", &opts);
            assert_eq!(result, "ABC_DEF_GHI");

            opts.keep = "_";
            let result = macro_case_with_options("ABC_DEF_GHI", &opts);
            assert_eq!(result, "ABC___DEF___GHI");
        }

        #[test]
        fn convert_cobol_case() {
            let mut opts = Options {
                separate_before_non_alphabets: true,
                separate_after_non_alphabets: true,
                separators: "",
                keep: "_",
            };
            let result = macro_case_with_options("ABC-DEF-GHI", &opts);
            assert_eq!(result, "ABC_DEF_GHI");

            opts.keep = "-";
            let result = macro_case_with_options("ABC-DEF-GHI", &opts);
            assert_eq!(result, "ABC_-_DEF_-_GHI");
        }

        #[test]
        fn convert_with_keeping_digits() {
            let mut opts = Options {
                separate_before_non_alphabets: true,
                separate_after_non_alphabets: true,
                separators: "",
                keep: "_",
            };
            let result = macro_case_with_options("abc123-456defG89HIJklMN12", &opts);
            assert_eq!(result, "ABC_123_456_DEF_G_89_HI_JKL_MN_12");

            opts.keep = "-";
            let result = macro_case_with_options("abc123-456defG89HIJklMN12", &opts);
            assert_eq!(result, "ABC_123-456_DEF_G_89_HI_JKL_MN_12");
        }

        #[test]
        fn convert_with_symbols_as_separators() {
            let opts = Options {
                separate_before_non_alphabets: true,
                separate_after_non_alphabets: true,
                separators: "",
                keep: ".~!#%?",
            };
            let result = macro_case_with_options(":.abc~!@def#$ghi%&jk(lm)no/?", &opts);
            assert_eq!(result, "._ABC_~!_DEF_#_GHI_%_JK_LM_NO_?");
        }

        #[test]
        fn convert_when_starting_with_digit() {
            let opts = Options {
                separate_before_non_alphabets: true,
                separate_after_non_alphabets: true,
                separators: "",
                keep: "-_",
            };
            let result = macro_case_with_options("123abc456def", &opts);
            assert_eq!(result, "123_ABC_456_DEF");

            let result = macro_case_with_options("123ABC456DEF", &opts);
            assert_eq!(result, "123_ABC_456_DEF");

            let result = macro_case_with_options("123Abc456Def", &opts);
            assert_eq!(result, "123_ABC_456_DEF");
        }

        #[test]
        fn convert_empty_string() {
            let opts = Options {
                separate_before_non_alphabets: true,
                separate_after_non_alphabets: true,
                separators: "",
                keep: "-_",
            };
            let result = macro_case_with_options("", &opts);
            assert_eq!(result, "");
        }
    }

    mod non_alphabets_as_part_of_a_word_with_kept_characters {
        use super::*;

        #[test]
        fn convert_camel_case() {
            let opts = Options {
                separate_before_non_alphabets: false,
                separate_after_non_alphabets: false,
                separators: "",
                keep: "-_",
            };
            let result = macro_case_with_options("abcDefGHIjk", &opts);
            assert_eq!(result, "ABC_DEF_GH_IJK");
        }

        #[test]
        fn convert_pascal_case() {
            let opts = Options {
                separate_before_non_alphabets: false,
                separate_after_non_alphabets: false,
                separators: "",
                keep: "-_",
            };
            let result = macro_case_with_options("AbcDefGHIjk", &opts);
            assert_eq!(result, "ABC_DEF_GH_IJK");
        }

        #[test]
        fn convert_snake_case() {
            let mut opts = Options {
                separate_before_non_alphabets: false,
                separate_after_non_alphabets: false,
                separators: "",
                keep: "-",
            };
            let result = macro_case_with_options("abc_def_ghi", &opts);
            assert_eq!(result, "ABC_DEF_GHI");

            opts.keep = "_";
            let result = macro_case_with_options("abc_def_ghi", &opts);
            assert_eq!(result, "ABC_DEF_GHI");
        }

        #[test]
        fn convert_kebab_case() {
            let mut opts = Options {
                separate_before_non_alphabets: false,
                separate_after_non_alphabets: false,
                separators: "",
                keep: "_",
            };
            let result = macro_case_with_options("abc-def-ghi", &opts);
            assert_eq!(result, "ABC_DEF_GHI");

            opts.keep = "-";
            let result = macro_case_with_options("abc-def-ghi", &opts);
            assert_eq!(result, "ABC-DEF-GHI");
        }

        #[test]
        fn convert_train_case() {
            let mut opts = Options {
                separate_before_non_alphabets: false,
                separate_after_non_alphabets: false,
                separators: "",
                keep: "_",
            };
            let result = macro_case_with_options("Abc-Def-Ghi", &opts);
            assert_eq!(result, "ABC_DEF_GHI");

            opts.keep = "-";
            let result = macro_case_with_options("Abc-Def-Ghi", &opts);
            assert_eq!(result, "ABC-_DEF-_GHI");
        }

        #[test]
        fn convert_macro_case() {
            let mut opts = Options {
                separate_before_non_alphabets: false,
                separate_after_non_alphabets: false,
                separators: "",
                keep: "-",
            };
            let result = macro_case_with_options("ABC_DEF_GHI", &opts);
            assert_eq!(result, "ABC_DEF_GHI");

            opts.keep = "_";
            let result = macro_case_with_options("ABC_DEF_GHI", &opts);
            assert_eq!(result, "ABC_DEF_GHI");
        }

        #[test]
        fn convert_cobol_case() {
            let mut opts = Options {
                separate_before_non_alphabets: false,
                separate_after_non_alphabets: false,
                separators: "",
                keep: "_",
            };
            let result = macro_case_with_options("ABC-DEF-GHI", &opts);
            assert_eq!(result, "ABC_DEF_GHI");

            opts.keep = "-";
            let result = macro_case_with_options("ABC-DEF-GHI", &opts);
            assert_eq!(result, "ABC-DEF-GHI");
        }

        #[test]
        fn convert_with_keeping_digits() {
            let mut opts = Options {
                separate_before_non_alphabets: false,
                separate_after_non_alphabets: false,
                separators: "",
                keep: "_",
            };
            let result = macro_case_with_options("abc123-456defG89HIJklMN12", &opts);
            assert_eq!(result, "ABC123_456DEF_G89HI_JKL_MN12");

            opts.keep = "-";
            let result = macro_case_with_options("abc123-456defG89HIJklMN12", &opts);
            assert_eq!(result, "ABC123-456DEF_G89HI_JKL_MN12");
        }

        #[test]
        fn convert_with_symbols_as_separators() {
            let opts = Options {
                separate_before_non_alphabets: false,
                separate_after_non_alphabets: false,
                separators: "",
                keep: ".~!#%?",
            };
            let result = macro_case_with_options(":.abc~!@def#$ghi%&jk(lm)no/?", &opts);
            assert_eq!(result, ".ABC~!_DEF#_GHI%_JK_LM_NO_?");
        }

        #[test]
        fn convert_when_starting_with_digit() {
            let opts = Options {
                separate_before_non_alphabets: false,
                separate_after_non_alphabets: false,
                separators: "",
                keep: "-_",
            };
            let result = macro_case_with_options("123abc456def", &opts);
            assert_eq!(result, "123ABC456DEF");

            let result = macro_case_with_options("123ABC456DEF", &opts);
            assert_eq!(result, "123ABC456DEF");

            let result = macro_case_with_options("123Abc456Def", &opts);
            assert_eq!(result, "123_ABC456_DEF");
        }

        #[test]
        fn convert_empty_string() {
            let opts = Options {
                separate_before_non_alphabets: false,
                separate_after_non_alphabets: false,
                separators: "",
                keep: "-_",
            };
            let result = macro_case_with_options("", &opts);
            assert_eq!(result, "");
        }
    }
}