test_gates 0.2.2

Test gates for the Dart and Flutter code that must not be wrong: per-file 100% line and branch coverage, static checks and mutation testing.

example/README.md

test_gates example

A package with two gates. lib/bulk_discount.dart and lib/shipping_fee.dart decide what a customer pays, so they are listed in test-gates.json. bin/estimate.dart uses them and prints; it is listed as a candidate, with what keeps it from being a gate.

dart pub get
dart run test_gates check       # the gates exist, have their tests, and are pure modules
dart run test_gates test        # dart test with coverage: 100% lines and branches of the gates
dart run test_gates selfcheck   # with unexecuted code in it, a gate fails
dart run test_gates timezones   # the tests in other time zones (nothing to run here: no gate names DateTime)
dart run test_gates mutation    # every small change to a gate is noticed by a test (the first run fetches the tool that runs them)

test_gates check: OK (2 gate(s), 1 candidate(s))

Things to try:

• Remove the test never charges more than the maximum from test/shipping_fee_test.dart. test fails: the block that limits the fee is never executed (2/3 branches taken).
• Remove the expectation for 50 items from test/bulk_discount_test.dart. test still passes, at 100%: every line and block is executed by the other cases. mutation fails and names the changes that nothing notices any more (>= → > and 50 → 51 in quantity >= 50).
• Add import 'dart:io'; to lib/shipping_fee.dart. check rejects it: a gate is a pure module.
• Remove both equivalentMutants from test-gates.json. mutation fails with the two mutants that no test can notice (> → >= where the fee is limited to the maximum, and 50 → 51 where the discount is rounded), and prints the entries to put back.

All of them in one start: dart run test_gates all. tool/test_gates.dart is the entry point for compiling the tool into an executable (dart compile exe tool/test_gates.dart -o build/test_gates), which starts faster still; the README of the package says when that is worth it.

In a package of your own, test_gates is a development dependency from pub.dev (dart pub add --dev test_gates), not a path.