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
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
//! # Pretty Assertions
//!
//! When writing tests in Rust, you'll probably use `assert_eq!(a, b)` _a lot_.
//!
//! If such a test fails, it will present all the details of `a` and `b`. 
//! But you have to spot the differences yourself, which is not always straightforward,
//! like here:
//!
//! ![standard assertion](https://raw.githubusercontent.com/colin-kiegel/rust-pretty-assertions/1a7feb17e1dfbeabfac91b0d5a9cb78dfb1bc065/examples/standard_assertion.png)
//!
//! Wouldn't that task be _much_ easier with a colorful diff?
//!
//! ![pretty assertion](https://raw.githubusercontent.com/colin-kiegel/rust-pretty-assertions/1a7feb17e1dfbeabfac91b0d5a9cb78dfb1bc065/examples/pretty_assertion.png)
//!
//! Yep — and you only need **one line of code** to make it happen:
//!
//! ```rust,ignore
//! #[macro_use] extern crate pretty_assertions;
//! ```
//!
//! <details>
//! <summary>Show the example behind the screenshots above.</summary>
//!
//! ```rust,ignore
//! // 1. add the `pretty_assertions` dependency to `Cargo.toml`.
//! // 2. insert this line at the top of your crate root or integration test
//! #[macro_use] extern crate pretty_assertions;
//!
//! fn main() {
//!     #[derive(Debug, PartialEq)]
//!     struct Foo {
//!         lorem: &'static str,
//!         ipsum: u32,
//!         dolor: Result<String, String>,
//!     }
//!
//!     let x = Some(Foo { lorem: "Hello World!", ipsum: 42, dolor: Ok("hey".to_string())});
//!     let y = Some(Foo { lorem: "Hello Wrold!", ipsum: 42, dolor: Ok("hey ho!".to_string())});
//!
//!     assert_eq!(x, y);
//! }
//! ```
//! </details>
//!
//! ## Tip
//!
//! Specify it as [`[dev-dependencies]`](http://doc.crates.io/specifying-dependencies.html#development-dependencies)
//! and it will only be used for compiling tests, examples, and benchmarks.
//! This way the compile time of `cargo build` won't be affected!
//!
//! In your crate root, also add `#[cfg(test)]` to the crate import, like this:
//!
//! ```rust,ignore
//! #[cfg(test)] // <-- not needed in examples + integration tests
//! #[macro_use]
//! extern crate pretty_assertions;
//! ```
//!
//! ## Note
//!
//! * Each example and integration test also needs `#[macro_use] extern crate
//!   pretty_assertions`, if you want colorful diffs there.
//! * The replacement is only effective in your own crate, not in other libraries
//!   you include.
//! * `assert_ne` is also switched to multi-line presentation, but does _not_ show
//!   a diff.

extern crate difference;
extern crate ansi_term;
mod format_changeset;

use std::fmt::{self, Debug, Display};
use difference::Changeset;

use format_changeset::format_changeset;
pub use ansi_term::Style;

#[doc(hidden)]
pub struct Comparison(Changeset);

impl Comparison {
    pub fn new<TLeft: Debug, TRight: Debug>(left: &TLeft, right: &TRight) -> Comparison {
        let left_dbg = format!("{:#?}", *left);
        let right_dbg = format!("{:#?}", *right);
        let changeset = Changeset::new(&left_dbg, &right_dbg, "\n");

        Comparison(changeset)
    }
}

impl Display for Comparison {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        format_changeset(f, &self.0)
    }
}

#[macro_export]
macro_rules! assert_eq {
    ($left:expr , $right:expr,) => ({
        assert_eq!($left, $right)
    });
    ($left:expr , $right:expr) => ({
        match (&($left), &($right)) {
            (left_val, right_val) => {
                if !(*left_val == *right_val) {
                    panic!("assertion failed: `(left == right)`\
                          \n\
                          \n{}\
                          \n",
                           $crate::Comparison::new(left_val, right_val))
                }
            }
        }
    });
    ($left:expr , $right:expr, $($arg:tt)*) => ({
        match (&($left), &($right)) {
            (left_val, right_val) => {
                if !(*left_val == *right_val) {
                    panic!("assertion failed: `(left == right)`: {}\
                          \n\
                          \n{}\
                          \n",
                           format_args!($($arg)*),
                           $crate::Comparison::new(left_val, right_val))
                }
            }
        }
    });
}

#[macro_export]
#[doc(hidden)]
macro_rules! __assert_ne {
    ($left:expr, $right:expr, $maybe_semicolon:expr, $($arg:tt)+) => ({
        match (&($left), &($right)) {
            (left_val, right_val) => {
                if *left_val == *right_val {
                  let left_dbg = format!("{:?}", *left_val);
                  let right_dbg = format!("{:?}", *right_val);
                  if left_dbg != right_dbg {

                      panic!("assertion failed: `(left != right)`{}{}\
                            \n\
                            \n{}\
                            \n{}: According to the `PartialEq` implementation, both of the values \
                              are partially equivalent, even if the `Debug` outputs differ.\
                            \n\
                            \n",
                             $maybe_semicolon,
                             format_args!($($arg)+),
                             $crate::Comparison::new(left_val, right_val),
                             $crate::Style::new()
                                 .bold()
                                 .underline()
                                 .paint("Note"))
                  }

                  panic!("assertion failed: `(left != right)`{}{}\
                        \n\
                        \n{}:\
                        \n{:#?}\
                        \n\
                        \n",
                         $maybe_semicolon,
                         format_args!($($arg)+),
                         $crate::Style::new().bold().paint("Both sides"),
                         left_val)
                }
            }
        }
    });
}

#[macro_export]
macro_rules! assert_ne {
    ($left:expr, $right:expr) => ({
        __assert_ne!($left, $right, "", "");
    });
    ($left:expr, $right:expr,) => ({
        __assert_ne!($left, $right, "", "");
    });
    ($left:expr, $right:expr, $($arg:tt)+) => ({
        __assert_ne!($left, $right, ": ", $($arg)+);
    });
}