1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140

/// Assert a values is equal to another.
///
/// * When true, return Result `Ok(())`.
///
/// * When true, return Result `Err` with a diagnostic message.
///
/// # Examples
///
/// ```rust
/// # #[macro_use] extern crate assertables;
/// # use std::panic;
/// # fn main() {
/// let x = assert_eq_as_result!(1, 1);
/// //-> Ok(())
/// assert!(x.is_ok());
///
/// let x = assert_eq_as_result!(1, 2);
/// //-> Err(…)
/// let actual = x.unwrap_err();
/// let expect = concat!(
///     "assertion failed: `assert_eq!(left, right)`\n",
///     "  left: `1`,\n",
///     " right: `2`"
/// );
/// assert_eq!(actual, expect);
/// # }
/// ```

///
#[macro_export]
macro_rules! assert_eq_as_result {
    ($a:expr, $b:expr $(,)?) => ({
        match (&$a, &$b) {
            (a_val, b_val) => {
                if a_val == b_val {
                    Ok(())
                } else {
                    Err(msg_with_left_and_right!("assertion failed", "assert_eq!", $a, $b))
                }
            }
        }
    });
}

#[cfg(test)]
mod test_x_result {

    #[test]
    fn test_assert_eq_as_result_x_arity_2_success() {
        let a: i32 = 1;
        let b: i32 = 1;
        let x = assert_eq_as_result!(a, b);
        assert!(x.is_ok());
    }

    #[test]
    fn test_assert_eq_as_result_x_arity_2_failure() {
        let a: i32 = 1;
        let b: i32 = 2;
        let x =  assert_eq_as_result!(a, b);
        assert_eq!(
            x.unwrap_err(),
            concat!(
                "assertion failed: `assert_eq!(left, right)`\n",
                "  left: `1`,\n",
                " right: `2`"
            )
        );
    }
}

/// Assert a value is equal to another.
///
/// * When true, return `()`.
///
/// * Otherwise, call [`panic!`] with a message and the values of the
///   expressions with their debug representations.
///
/// # Examples
///
/// ```rust
/// # #[macro_use] extern crate assertables;
/// # use std::panic;
/// # fn main() {
/// assert_eq!(1, 1);
/// //-> ()
///
/// let result = panic::catch_unwind(|| {
/// assert_eq!(1, 2);
/// //-> panic!
/// });
/// let actual = result.unwrap_err().downcast::<String>().unwrap().to_string();
/// let expect = concat!(
///     "assertion failed: `(left == right)`\n",
///     "  left: `1`,\n",
///     " right: `2`"
/// );
/// assert_eq!(actual, expect);
/// # }
/// ```


// `assert_eq` macro is provided by Rust `std`.

#[cfg(test)]
mod test_x_panic {

    #[test]
    fn test_assert_eq_x_arity_2_success() {
        let a: i32 = 1;
        let b: i32 = 1;
        let x = assert_eq!(a, b);
        assert_eq!(x, ());
    }

    #[test]
    #[should_panic (expected = "assertion failed: `(left == right)`\n  left: `1`,\n right: `2`")]
    fn test_assert_eq_x_arity_2_failure() {
        let a: i32 = 1;
        let b: i32 = 2;
        assert_eq!(a, b);
    }

    #[test]
    fn test_assert_eq_x_arity_3_success() {
        let a: i32 = 1;
        let b: i32 = 1;
        let x = assert_eq!(a, b, "message");
        assert_eq!(x, ());
    }

    #[test]
    #[should_panic (expected = "message")]
    fn test_assert_eq_x_arity_3_failure() {
        let a: i32 = 1;
        let b: i32 = 2;
        assert_eq!(a, b, "message");
    }

}