zig-testing

Write test blocks directly in your Zig source files using the built-in test keyword, then run them with zig test src/main.zig. Use std.testing assertions like testing.expectEqual and testing.expect, prefixing each call with try.

Use std.testing.allocator instead of a general-purpose allocator in your tests. It automatically detects leaks when the test ends, failing the test if allocated memory was not freed, so pair it with defer-based deinit calls.

Yes, Zig has first-class testing built into the compiler with no external dependencies. Test blocks are discovered by zig test, can run at compile time via comptime, and can be wired into build.zig with b.addTest and a test step.

Zig has no built-in coverage, so use external tools like kcov on Linux/macOS or the community zcoverage tool. Build a Debug test binary with zig build test, then run kcov with include and exclude patterns to generate an HTML report.

Flakiness usually comes from std.time.sleep synchronization, real network or filesystem dependencies, or random inputs without fixed seeds. Use atomic operations for synchronization, testing.allocator for leak checks, and std.Random with a deterministic seed.

Avoid generating tests when the code has zero testability, such as all-comptime logic with no runtime API or hard-coded system calls. Also stop when no test blocks or build.zig test step exist, or when tests would require real credentials or production access.