Zig Test

detect_test.zig

$ zig test detect_test.zig
Test 1/1 builtin.is_test...OK
All tests passed.

Zig has lazy top level declaration analysis, which means that if a function is not called, or otherwise used, it is not analyzed. This means that there may be an undiscovered compile error in a function because it is never called.

unused_fn.zig

fn unused() i32 {
    return "wrong return type";
}
test "unused function" { }

pub fn assert(ok: bool) void {

This means that when testing in ReleaseFast or ReleaseSmall mode, assert is not sufficient to check the result of a computation:

assert.zig

const std = @import("std");
const assert = std.debug.assert;
test "assert in release fast mode" {
    assert(false);
}

Note that although the above example shows the test passing, this is invoking unchecked . This documentation is showing only one possible outcome of this test.

test.zig

const std = @import("std");
    expect(false);
}

$ zig test test.zig --release-fast
Test 1/1 assert in release fast mode...test failure
Tests failed. Use the following command to reproduce the failure:

See the rest of the std.testing namespace for more available functions.

zig test has a few command line parameters which affect the compilation. See zig --help for a full list. The most interesting one is --test-filter [text]. This makes the test build only include tests whose name contains the supplied filter text. Again, thanks to lazy analysis, this can allow you to narrow a build to only a few functions in isolation.