Not included in the build by default, since it's fragile and kludgy. Do something like this to run it: cd doc/tutorial RUSTC=../../build/stage2/bin/rustc bash test.sh Closes #1143
2.0 KiB
Testing
The Rust language has a facility for testing built into the language.
Tests can be interspersed with other code, and annotated with the
#[test]
attribute.
use std;
fn twice(x: int) -> int { x + x }
#[test]
fn test_twice() {
let i = -100;
while i < 100 {
assert twice(i) == 2 * i;
i += 1;
}
}
When you compile the program normally, the test_twice
function will
not be used. To actually run the tests, compile with the --test
flag:
## notrust
> rustc --lib twice.rs
> ./twice
running 1 tests
test test_twice ... ok
result: ok. 1 passed; 0 failed; 0 ignored
Or, if we change the file to fail, for example by replacing x + x
with x + 1
:
## notrust
running 1 tests
test test_twice ... FAILED
failures:
test_twice
result: FAILED. 0 passed; 1 failed; 0 ignored
You can pass a command-line argument to a program compiled with
--test
to run only the tests whose name matches the given string. If
we had, for example, test functions test_twice
, test_once_1
, and
test_once_2
, running our program with ./twice test_once
would run
the latter two, and running it with ./twice test_once_2
would run
only the last.
To indicate that a test is supposed to fail instead of pass, you can
give it a #[should_fail]
attribute.
use std;
fn divide(a: float, b: float) -> float {
if b == 0f { fail; }
a / b
}
#[test]
#[should_fail]
fn divide_by_zero() { divide(1f, 0f); }
To disable a test completely, add an #[ignore]
attribute. Running a
test runner (the program compiled with --test
) with an --ignored
command-line flag will cause it to also run the tests labelled as
ignored.
A program compiled as a test runner will have the configuration flag
test
defined, so that you can add code that won't be included in a
normal compile with the #[cfg(test)]
attribute (see conditional
compilation).