Testing

1 min read

Tests describe behavior you want to keep working. Mark a function with @test, use assertions to check its results, and run it with dreamer test or dream test. A failed assertion stops the test and reports the problem.

Import: import system.testing;

Mark tests with @test, then run dream test or dreamer test. A failed assertion prints a message and exits (no exceptions).

import system;
import system.testing;

@test
fun addition_works(): void {
    Assert.eq(2 + 2, 4);
}

dream test path/to/file.dream
dream test tests/
dreamer test
dream test --filter addition tests/

@test is for a top-level fun name(): void or async fun name(): void, never main. Test files must not declare main. Put tests in a test project (type = "test") or a package's tests/ folder; see Test a project.

@timeout(ms) sets a limit for one test. There is no default limit.

@test
@timeout(500)
fun parses_quickly(): void {
    Assert.eq(parse("1 + 2"), 3);
}

dream test builds one runner that calls Test.run for each test. You can also call it from your own main:

fun main() {
    Test.run(
        "addition works",
        () => {
            Assert.eq(2 + 2, 4);
        }
    );
}

Test.run(name, body) prints RUN <name> before the body and PASS <name> after it. When the body leaves more live objects than it found, it prints LEAK <name> live=+N first. Test.run_with_timeout(name, ms, body) also prints the limit (RUN <name> timeout=<ms>); dream test enforces it.

Call	Meaning
Assert.eq / Assert.ne	equal / not equal
Assert.is_true / is_false	bool
Assert.approx(a, b, eps)	floats
Assert.eq	strings
Assert.fail(message)	fail now