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lib: add helpers for generating custom assert_{eq,ne} macros
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@tommilligan
tommilligan committed May 6, 2021
1 parent 55f9b7a commit ab6d726
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Showing 11 changed files with 475 additions and 108 deletions.
2 changes: 2 additions & 0 deletions Cargo.toml
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Expand Up @@ -3,4 +3,6 @@
members = [
"pretty_assertions",
"pretty_assertions_bench",
"pretty_assertions_derive",
"pretty_assertions_derive_tests",
]
1 change: 1 addition & 0 deletions pretty_assertions/Cargo.toml
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Expand Up @@ -23,6 +23,7 @@ travis-ci = { repository = "colin-kiegel/rust-pretty-assertions" }
[dependencies]
ansi_term = "0.12.1"
diff = "0.1.12"
pretty_assertions_derive = { version = "0.1.0", path = "../pretty_assertions_derive" }

[target.'cfg(windows)'.dependencies]
output_vt100 = "0.1.2"
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190 changes: 82 additions & 108 deletions pretty_assertions/src/lib.rs
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Expand Up @@ -126,115 +126,89 @@ where
}
}

/// Asserts that two expressions are equal to each other (using [`PartialEq`]).
///
/// On panic, this macro will print a diff derived from [`Debug`] representation of
/// each value.
///
/// This is a drop in replacement for [`std::assert_eq!`].
/// You can provide a custom panic message if desired.
///
/// # Examples
///
/// ```
/// use pretty_assertions::assert_eq;
///
/// let a = 3;
/// let b = 1 + 2;
/// assert_eq!(a, b);
///
/// assert_eq!(a, b, "we are testing addition with {} and {}", a, b);
/// ```
#[macro_export]
macro_rules! assert_eq {
($left:expr, $right:expr$(,)?) => ({
$crate::assert_eq!(@ $left, $right, "", "");
});
($left:expr, $right:expr, $($arg:tt)*) => ({
$crate::assert_eq!(@ $left, $right, ": ", $($arg)+);
});
(@ $left:expr, $right:expr, $maybe_semicolon:expr, $($arg:tt)*) => ({
match (&($left), &($right)) {
(left_val, right_val) => {
if !(*left_val == *right_val) {
::std::panic!("assertion failed: `(left == right)`{}{}\
\n\
\n{}\
\n",
$maybe_semicolon,
format_args!($($arg)*),
$crate::Comparison::new(left_val, right_val)
)
}
}
}
});
pretty_assertions_derive::derive_assert_eq! {
/// Asserts that two expressions are equal to each other (using [`PartialEq`]).
///
/// On panic, this macro will print a diff derived from [`Debug`] representation of
/// each value.
///
/// This is a drop in replacement for [`std::assert_eq!`].
/// You can provide a custom panic message if desired.
///
/// # Examples
///
/// ```
/// use pretty_assertions::assert_eq;
///
/// let a = 3;
/// let b = 1 + 2;
/// assert_eq!(a, b);
///
/// assert_eq!(a, b, "we are testing addition with {} and {}", a, b);
/// ```
(assert_eq, |left_val, right_val, has_message, message| {
::std::panic!("assertion failed: `(left == right)`{}{}\
\n\
\n{}\
\n",
if has_message { ": " } else { "" },
message,
$crate::Comparison::new(left_val, right_val)
)
})
}

/// Asserts that two expressions are not equal to each other (using [`PartialEq`]).
///
/// On panic, this macro will print the values of the expressions with their
/// [`Debug`] representations.
///
/// This is a drop in replacement for [`std::assert_ne!`].
/// You can provide a custom panic message if desired.
///
/// # Examples
///
/// ```
/// use pretty_assertions::assert_ne;
///
/// let a = 3;
/// let b = 2;
/// assert_ne!(a, b);
///
/// assert_ne!(a, b, "we are testing that the values are not equal");
/// ```
#[macro_export]
macro_rules! assert_ne {
($left:expr, $right:expr$(,)?) => ({
$crate::assert_ne!(@ $left, $right, "", "");
});
($left:expr, $right:expr, $($arg:tt)+) => ({
$crate::assert_ne!(@ $left, $right, ": ", $($arg)+);
});
(@ $left:expr, $right:expr, $maybe_semicolon:expr, $($arg:tt)+) => ({
match (&($left), &($right)) {
(left_val, right_val) => {
if *left_val == *right_val {
let left_dbg = ::std::format!("{:?}", &*left_val);
let right_dbg = ::std::format!("{:?}", &*right_val);
if left_dbg != right_dbg {
::std::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")
)
}

::std::panic!("assertion failed: `(left != right)`{}{}\
\n\
\n{}:\
\n{:#?}\
\n\
\n",
$maybe_semicolon,
format_args!($($arg)+),
$crate::Style::new().bold().paint("Both sides"),
left_val
)
}
}
pretty_assertions_derive::derive_assert_ne! {
/// Asserts that two expressions are not equal to each other (using [`PartialEq`]).
///
/// On panic, this macro will print the values of the expressions with their
/// [`Debug`] representations.
///
/// This is a drop in replacement for [`std::assert_ne!`].
/// You can provide a custom panic message if desired.
///
/// # Examples
///
/// ```
/// use pretty_assertions::assert_ne;
///
/// let a = 3;
/// let b = 2;
/// assert_ne!(a, b);
///
/// assert_ne!(a, b, "we are testing that the values are not equal");
/// ```
(assert_ne, |left_val, right_val, has_message, message| {
let left_dbg = ::std::format!("{:?}", &*left_val);
let right_dbg = ::std::format!("{:?}", &*right_val);
if left_dbg != right_dbg {
::std::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",
if has_message { ": " } else { "" },
message,
$crate::Comparison::new(left_val, right_val),
$crate::Style::new()
.bold()
.underline()
.paint("Note")
)
}
});

::std::panic!("assertion failed: `(left != right)`{}{}\
\n\
\n{}:\
\n{:#?}\
\n\
\n",
if has_message { ": " } else { "" },
message,
$crate::Style::new().bold().paint("Both sides"),
left_val
)
})
}
1 change: 1 addition & 0 deletions pretty_assertions_bench/Cargo.toml
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Expand Up @@ -3,6 +3,7 @@ name = "pretty_assertions_bench"
version = "0.1.0"
authors = ["Tom Milligan <code@tommilligan.net>"]
edition = "2018"
publish = false

[dependencies]
criterion = { version = "0.3.4", features = ["html_reports"] }
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12 changes: 12 additions & 0 deletions pretty_assertions_derive/Cargo.toml
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@@ -0,0 +1,12 @@
[package]
name = "pretty_assertions_derive"
version = "0.1.0"
edition = "2018"

[lib]
proc-macro = true

[dependencies]
proc-macro2 = "1.0.26"
quote = "1.0.9"
syn = { version = "1.0.71", features = ["full"] }

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