Testing

A test is a top-level function marked @test. The contract is strict and every part of it is checked: top level, not extern, not generic, no parameters, returns void.

import Test from "std::test";

@test
function smoke(): void {
    Test::assert(true);
    return;
}

Run them with ignis test, in a project or against a single file.

Assertions

import String from "std::string";
import Test from "std::test";

@test
function checks(): void {
    Test::assert(2 + 2 == 4);
    Test::assertEq<String>(String::create("same"), String::create("same"));
    Test::assertNe<i32>(1, 2);
    Test::assertEq<str>("abc", "abc");
    return;
}

assertEq<T> and assertNe<T> route through canonical equality: std::hash::Eq for records and enums, the builtin @eq<T> underneath. A type that does not support equality is rejected during analysis — the failure arrives as a diagnostic, not as a crash in generated code.

Snapshots

A snapshot assertion compares against a stored baseline instead of a value written in the test.

import Test from "std::test";

@test
function snapshotText(): void {
    Test::assertSnapshot("rendered", "hello snapshot\n");
    return;
}

@test
function snapshotFile(): void {
    Test::assertFileSnapshot("artifact", "./actual-output.txt");
    return;
}

Baselines live in a __snapshots__/ directory next to the module under test. File names are deterministic and escaped, so two modules can use the same label without colliding.

ignis test --update-snapshots

With update mode, missing baselines are created and mismatched ones replaced. Without it, both cases fail — which is what you want in CI.

One thing to watch: project mode and single-file mode use different roots. A snapshot written while running one file is not the one found when running the project.

Failure reporting

Tests run in a deterministic order and the runner keeps going after a failure, so one broken test does not hide the rest. Failed tests print bounded excerpts of stdout and stderr rather than everything the process emitted.

A snapshot mismatch reports the reason, the path to the baseline, and the expected and actual byte counts.