3 releases
0.1.2 | Dec 30, 2023 |
---|---|
0.1.1 | Jun 7, 2023 |
0.1.0 | Jun 7, 2023 |
#326 in Testing
39KB
1K
SLoC
Expect Tests
Expect Tests is a Rust crate inspired by rust-analyzer's expect-test. Explanation can be found here.
Basic Usage:
expect!(fibonacci(15), "610");
The macro uses the Debug trait representation (except for string literals) and compares it to the provided string literal. In case of a mismatch, an error with a diff will be shown:
You can update all `expect!` tests by running:
UPDATE_EXPECT=1 cargo test
To update a single test, place the cursor on `expect` token and use the `run` feature of rust-analyzer.
Expect:
----
987
----
Actual:
----
610
----
Diff:
----
987610
----
If the UPDATE_EXPECT
environment variable is set, the macro will directly update the source file to fix it. For example:
expect!(fibonacci(15));
After running UPDATE_EXPECT=1 cargo test
, your source file should automatically be updated to:
expect!(fibonacci(15), "610");
Multiple Expects:
Testing callbacks can be cumbersome because you'd need to collect into a vec. Here's an alternative using expect!
:
fn some_complicated_io_func(callback: impl Fn(i32)) {
callback(5);
callback(3);
callback(10);
}
some_complicated_io_func(|status_value| {
expect!(status_value, "5", "3", "10");
});
Caveat: Expect-tests cannot detect when the expect!
macro is never called. Therefore, a loop like the following will pass even though "2", "3", and "4" are never run:
for i in 0..2 {
expect!(i, "0", "1", "2", "3", "4");
}
Expect Tokens:
Testing proc macros is now easier with expect tokens:
#[test]
fn test_enum() {
let output = quote! {
enum TrafficLight {
Red,
Yellow,
Green
}
};
expect_tokens!(
output,
r#"
enum TrafficLight {
Red,
Yellow,
Green,
}
"#
);
}
Examples:
Check out the examples used to test this crate.
Alternatives:
Other Notes:
- Makes a "best effort" to comply with rustfmt. When the macro detects a multiline expect, updating will attempt to insert newlines where appropriate.
- Indentations are ignored in the string literals when comparing to make the code look nicer.
Dependencies
~95–360KB