Testing

Run the unit tests with make test. Each tests/test_*.mojo file uses the standard library's TestSuite to discover its test_ functions. CI runs the same suite with Mojo 1.0.0 and 1.1.0 on Linux x86-64, Linux ARM64, and macOS ARM64, sequentially per platform.

make test
make test TEST_FILES=tests/test_iana.mojo
uv run mojo run -I . tests/test_iana.mojo --only test_gap_fold_offsets_and_dst
uv run mojo run -I . tests/test_iana.mojo --skip-all

--only selects test functions; --skip excludes them; --skip-all collects them without executing their bodies. A collection-only run is not a passing validation run. Test failures make the command exit unsuccessfully.

What is checked

Suite	Main checks
Core and contracts	Construction, leap centuries, bounds, shifts, mixed timezone awareness, comparison, serialization
Parsing and formatting	ISO and token formats, fallback lists, extraction boundaries, Unicode literals, invalid inputs, timestamp unit normalization
Timezones	Historical offsets, DST folds/gaps, southern hemisphere seasons, half-hour transitions, skipped days, negative fractional instants
Locale	All months and weekdays, AM/PM boundaries, aliases, unsupported languages, Chinese relative units and malformed input
Iterators	Laziness, independent copies, exhaustion, zero limits, reversed ranges, clipping, partial groups, DST hour sequences
Properties	Ordinal, timestamp, duration, fixed-offset, localized date, and IANA conversion invariants

The property suite runs 1,000 samples per property (6,000 total) with fixed seeds using std.testing.prop.Rng. Failures include relevant input context; seeds live beside each test. The same inputs run on both compiler versions. Explicit examples cover boundaries that random sampling may miss. One test function can contain many examples; neither function counts nor sample counts measure source coverage.

The official PropTest runner is available too. A minimal runner probe compiled on 1.1 but failed with a generic callback type error on the tested 1.0 compiler, so this project uses the shared seeded generator directly rather than different property suites per compiler.

Coverage and tooling status

Checked against Mojo 1.0.0 and 1.1.0 on September 22, 2026:

• TestSuite provides discovery, selection, skips, timing, and result reports.
• assert_raises(contains=...) validates expected errors and their messages.
• std.testing.prop provides generators and property-test infrastructure.
• No supported line/branch coverage command or instrumentation option is documented in the CLI. Both tested compilers reject mojo build --coverage. This project does not publish a source-coverage percentage.
• --sanitize address and --sanitize thread are experimental runtime checks, not coverage measurement. The local macOS 1.1 probe could not link/load the required ASan runtime symbols; sanitizer checks are not claimed as passing or required CI checks.

Official references: TestSuite, assert_raises, property testing, compiler options.