assertables/assert_fn/

assert_fn_eq.rs

//! Assert a function output is equal to another.
//!
//! Pseudocode:<br>
//! a_function(a) == b_function(b)
//!
//! # Example
//!
//! ```rust
//! use assertables::*;
//!
//! let a: i8 = -1;
//! let b: i8 = 1;
//! assert_fn_eq!(i8::abs, a, i8::abs, b);
//! ```
//!
//! # Module macros
//!
//! * [`assert_fn_eq`](macro@crate::assert_fn_eq)
//! * [`assert_fn_eq_as_result`](macro@crate::assert_fn_eq_as_result)
//! * [`debug_assert_fn_eq`](macro@crate::debug_assert_fn_eq)

/// Assert a function output is equal to another.
///
/// Pseudocode:<br>
/// a_function(a) == b_function(b)
///
/// * If true, return Result `Ok(a, b)`.
///
/// * Otherwise, return Result `Err(message)`.
///
/// This macro is useful for runtime checks, such as checking parameters,
/// or sanitizing inputs, or handling different results in different ways.
///
/// # Module macros
///
/// * [`assert_fn_eq`](macro@crate::assert_fn_eq)
/// * [`assert_fn_eq_as_result`](macro@crate::assert_fn_eq_as_result)
/// * [`debug_assert_fn_eq`](macro@crate::debug_assert_fn_eq)
///
#[macro_export]
macro_rules! assert_fn_eq_as_result {

    //// Arity 1

    ($a_function:path, $a_param:expr, $b_function:path, $b_param:expr $(,)?) => {{
        match (&$a_function, &$a_param, &$b_function, &$b_param) {
            (_a_function, a_param, _b_function, b_param) => {
                let a = $a_function($a_param);
                let b = $b_function($b_param);
                if a == b {
                    Ok((a, b))
                } else {
                    Err(
                        format!(
                            concat!(
                                "assertion failed: `assert_fn_eq!(a_function, a_param, b_function, b_param)`\n",
                                "https://docs.rs/assertables/9.5.6/assertables/macro.assert_fn_eq.html\n",
                                " a_function label: `{}`,\n",
                                "    a_param label: `{}`,\n",
                                "    a_param debug: `{:?}`,\n",
                                " b_function label: `{}`,\n",
                                "    b_param label: `{}`,\n",
                                "    b_param debug: `{:?}`,\n",
                                "                a: `{:?}`,\n",
                                "                b: `{:?}`"
                            ),
                            stringify!($a_function),
                            stringify!($a_param),
                            a_param,
                            stringify!($b_function),
                            stringify!($b_param),
                            b_param,
                            a,
                            b
                        )
                    )
                }
            }
        }
    }};

    //// Arity 0

    ($a_function:path, $b_function:path) => {{
        let a = $a_function();
        let b = $b_function();
        if a == b {
            Ok((a, b))
        } else {
            Err(
                format!(
                    concat!(
                        "assertion failed: `assert_fn_eq!(a_function, b_function)`\n",
                        "https://docs.rs/assertables/9.5.6/assertables/macro.assert_fn_eq.html\n",
                        " a_function label: `{}`,\n",
                        " b_function label: `{}`,\n",
                        "                a: `{:?}`,\n",
                        "                b: `{:?}`"
                    ),
                    stringify!($a_function),
                    stringify!($b_function),
                    a,
                    b
                )
            )
        }
    }};

}

#[cfg(test)]
mod test_assert_fn_eq_as_result {
    use std::sync::Once;

    mod arity_1 {

        fn f(i: i8) -> i8 {
            return i;
        }

        fn g(i: i8) -> i8 {
            return i;
        }

        #[test]
        fn eq() {
            let a: i8 = 1;
            let b: i8 = 1;
            let actual = assert_fn_eq_as_result!(f, a, g, b);
            assert_eq!(actual.unwrap(), (1, 1));
        }

        #[test]
        fn ne() {
            let a: i8 = 1;
            let b: i8 = 2;
            let actual = assert_fn_eq_as_result!(f, a, g, b);
            let message = concat!(
                "assertion failed: `assert_fn_eq!(a_function, a_param, b_function, b_param)`\n",
                "https://docs.rs/assertables/9.5.6/assertables/macro.assert_fn_eq.html\n",
                " a_function label: `f`,\n",
                "    a_param label: `a`,\n",
                "    a_param debug: `1`,\n",
                " b_function label: `g`,\n",
                "    b_param label: `b`,\n",
                "    b_param debug: `2`,\n",
                "                a: `1`,\n",
                "                b: `2`"
            );
            assert_eq!(actual.unwrap_err(), message);
        }
    }

    mod arity_0 {

        fn f() -> i8 {
            return 1;
        }

        fn g() -> i8 {
            return 2;
        }

        #[test]
        fn eq() {
            let actual = assert_fn_eq_as_result!(f, f);
            assert_eq!(actual.unwrap(), (1, 1));
        }

        #[test]
        fn ne() {
            let actual = assert_fn_eq_as_result!(f, g);
            let message = concat!(
                "assertion failed: `assert_fn_eq!(a_function, b_function)`\n",
                "https://docs.rs/assertables/9.5.6/assertables/macro.assert_fn_eq.html\n",
                " a_function label: `f`,\n",
                " b_function label: `g`,\n",
                "                a: `1`,\n",
                "                b: `2`"
            );
            assert_eq!(actual.unwrap_err(), message);
        }
    }
}

/// Assert a function output is equal to another.
///
/// Pseudocode:<br>
/// a_function(a) == b_function(b)
///
/// * If true, return `(a, b)`.
///
/// * Otherwise, call [`panic!`] with a message and the values of the
///   expressions with their debug representations.
///
/// # Examples
///
/// ```rust
/// use assertables::*;
/// # use std::panic;
///
/// # fn main() {
/// let a: i8 = -1;
/// let b: i8 = 1;
/// assert_fn_eq!(i8::abs, a, i8::abs, b);
///
/// # let result = panic::catch_unwind(|| {
/// // This will panic
/// let a: i8 = -1;
/// let b: i8 = 2;
/// assert_fn_eq!(i8::abs, a, i8::abs, b);
/// # });
/// // assertion failed: `assert_fn_eq!(a_function, a_param, b_function, b_param)`
/// // https://docs.rs/assertables/9.5.6/assertables/macro.assert_fn_eq.html
/// //  a_function label: `i8::abs`,
/// //     a_param label: `a`,
/// //     a_param debug: `-1`,
/// //  b_function label: `i8::abs`,
/// //     b_param label: `b`,
/// //     b_param debug: `2`,
/// //                 a: `1`,
/// //                 b: `2`
/// # let actual = result.unwrap_err().downcast::<String>().unwrap().to_string();
/// # let message = concat!(
/// #     "assertion failed: `assert_fn_eq!(a_function, a_param, b_function, b_param)`\n",
/// #     "https://docs.rs/assertables/9.5.6/assertables/macro.assert_fn_eq.html\n",
/// #     " a_function label: `i8::abs`,\n",
/// #     "    a_param label: `a`,\n",
/// #     "    a_param debug: `-1`,\n",
/// #     " b_function label: `i8::abs`,\n",
/// #     "    b_param label: `b`,\n",
/// #     "    b_param debug: `2`,\n",
/// #     "                a: `1`,\n",
/// #     "                b: `2`"
/// # );
/// # assert_eq!(actual, message);
/// # }
/// ```
///
/// # Module macros
///
/// * [`assert_fn_eq`](macro@crate::assert_fn_eq)
/// * [`assert_fn_eq_as_result`](macro@crate::assert_fn_eq_as_result)
/// * [`debug_assert_fn_eq`](macro@crate::debug_assert_fn_eq)
///
#[macro_export]
macro_rules! assert_fn_eq {

    //// Arity 1

    ($a_function:path, $a_param:expr, $b_function:path, $b_param:expr $(,)?) => {{
        match $crate::assert_fn_eq_as_result!($a_function, $a_param, $b_function, $b_param) {
            Ok(x) => x,
            Err(err) => panic!("{}", err),
        }
    }};

    ($a_function:path, $a_param:expr, $b_function:path, $b_param:expr, $($message:tt)+) => {{
        match $crate::assert_fn_eq_as_result!($a_function, $a_param, $b_function, $b_param) {
            Ok(x) => x,
            Err(err) => panic!("{}\n{}", format_args!($($message)+), err),
        }
    }};

    //// Arity 0

    ($a_function:path, $b_function:path) => {{
        match $crate::assert_fn_eq_as_result!($a_function, $b_function) {
            Ok(x) => x,
            Err(err) => panic!("{}", err),
        }
    }};

    ($a_function:path, $b_function:path, $($message:tt)+) => {{
        match $crate::assert_fn_eq_as_result!($a_function, $b_function) {
            Ok(x) => x,
            Err(err) => panic!("{}\n{}", format_args!($($message)+), err),
        }
    }};

}

#[cfg(test)]
mod test_assert_fn_eq {
    use std::panic;

    mod arity_1 {
        use super::*;

        fn f(i: i8) -> i8 {
            return i;
        }

        fn g(i: i8) -> i8 {
            return i;
        }

        #[test]
        fn eq() {
            let a: i8 = 1;
            let b: i8 = 1;
            let actual = assert_fn_eq!(f, a, g, b);
            assert_eq!(actual, (1, 1));
        }

        #[test]
        fn ne() {
            let result = panic::catch_unwind(|| {
                let a: i8 = 1;
                let b: i8 = 2;
                let _actual = assert_fn_eq!(f, a, g, b);
            });
            let message = concat!(
                "assertion failed: `assert_fn_eq!(a_function, a_param, b_function, b_param)`\n",
                "https://docs.rs/assertables/9.5.6/assertables/macro.assert_fn_eq.html\n",
                " a_function label: `f`,\n",
                "    a_param label: `a`,\n",
                "    a_param debug: `1`,\n",
                " b_function label: `g`,\n",
                "    b_param label: `b`,\n",
                "    b_param debug: `2`,\n",
                "                a: `1`,\n",
                "                b: `2`"
            );
            assert_eq!(
                result
                    .unwrap_err()
                    .downcast::<String>()
                    .unwrap()
                    .to_string(),
                message
            );
        }
    }

    mod arity_0 {
        use super::*;

        fn f() -> i8 {
            return 1;
        }

        fn g() -> i8 {
            return 2;
        }

        #[test]
        fn eq() {
            let actual = assert_fn_eq!(f, f);
            assert_eq!(actual, (1, 1));
        }

        #[test]
        fn ne() {
            let result = panic::catch_unwind(|| {
                let _actual = assert_fn_eq!(f, g);
            });
            let message = concat!(
                "assertion failed: `assert_fn_eq!(a_function, b_function)`\n",
                "https://docs.rs/assertables/9.5.6/assertables/macro.assert_fn_eq.html\n",
                " a_function label: `f`,\n",
                " b_function label: `g`,\n",
                "                a: `1`,\n",
                "                b: `2`"
            );
            assert_eq!(
                result
                    .unwrap_err()
                    .downcast::<String>()
                    .unwrap()
                    .to_string(),
                message
            );
        }
    }
}

/// Assert a function output is equal to another.
///
/// Pseudocode:<br>
/// a_function(a) == b_function(b)
///
/// This macro provides the same statements as [`assert_fn_eq`](macro.assert_fn_eq.html),
/// except this macro's statements are only enabled in non-optimized
/// builds by default. An optimized build will not execute this macro's
/// statements unless `-C debug-assertions` is passed to the compiler.
///
/// This macro is useful for checks that are too expensive to be present
/// in a release build but may be helpful during development.
///
/// The result of expanding this macro is always type checked.
///
/// An unchecked assertion allows a program in an inconsistent state to
/// keep running, which might have unexpected consequences but does not
/// introduce unsafety as long as this only happens in safe code. The
/// performance cost of assertions, however, is not measurable in general.
/// Replacing `assert*!` with `debug_assert*!` is thus only encouraged
/// after thorough profiling, and more importantly, only in safe code!
///
/// This macro is intended to work in a similar way to
/// [`::std::debug_assert`](https://doc.rust-lang.org/std/macro.debug_assert.html).
///
/// # Module macros
///
/// * [`assert_fn_eq`](macro@crate::assert_fn_eq)
/// * [`assert_fn_eq`](macro@crate::assert_fn_eq)
/// * [`debug_assert_fn_eq`](macro@crate::debug_assert_fn_eq)
///
#[macro_export]
macro_rules! debug_assert_fn_eq {
    ($($arg:tt)*) => {
        if $crate::cfg!(debug_assertions) {
            $crate::assert_fn_eq!($($arg)*);
        }
    };
}