src/doc/style/testing/unit.md

   1 % Unit testing
   2
   3 Unit tests should live in a `tests` submodule at the bottom of the module they
   4 test. Mark the `tests` submodule with `#[cfg(test)]` so it is only compiled when
   5 testing.
   6
   7 The `tests` module should contain:
   8
   9 * Imports needed only for testing.
  10 * Functions marked with `#[test]` striving for full coverage of the parent module's
  11   definitions.
  12 * Auxiliary functions needed for writing the tests.
  13
  14 For example:
  15
  16 ``` rust
  17 // Excerpt from std::str
  18
  19 #[cfg(test)]
  20 mod tests {
  21     #[test]
  22     fn test_eq() {
  23         assert!((eq(&"".to_owned(), &"".to_owned())));
  24         assert!((eq(&"foo".to_owned(), &"foo".to_owned())));
  25         assert!((!eq(&"foo".to_owned(), &"bar".to_owned())));
  26     }
  27 }
  28 ```
  29
  30 > **[FIXME]** add details about useful macros for testing, e.g. `assert!`