Tests¶
Tachi makes extensive use of tests to ensure code is of high quality when its released.
Running Tests¶
Tests are ran with node-tap.
You can run the server test suite with the following script:
pnpm test
This will execute every test, and also perform coverage analysis.
Bug
This may or may not impact you depending on how
dependencies install, but tap requires ts-node
and typescript to also be installed.
Otherwise, you will get a
cannot use import outside of module
error, which indicates that our typescript hasn't
been transpiled.
Writing Tests¶
Tests should be located in the same folder as the file they're testing, and tests should only ever test exports from one file at a time.
Tests should call things like ResetDBState and CloseAllConnections as lifecycle hooks to ensure
the file exits.
Tests should use the extension .test.ts, and keep
the same filename as the file they are testing.
Coverage¶
Coverage should be kept above 80%. New code should be tested.
Pull Requests will be rejected if they contain significant changes that are untested!
Single Process TAP¶
Since we don't mock our MongoDB install out, we run a real instance of Mongo for our tests, and run against it.
TAP runs every test file in isolation. This is a good idea normally, as it means state is never shared across files, and nothing bad is generally going to happen.
However, it takes around 2 seconds to connect to the MongoDB server when a new test file is started. These 2 seconds add up over the course of a ~1500 test file suite, and result in tests taking over 15-20 minutes.
To get around this, we use a Single Process TAP hack, which rolls all of our test files up into one test file.
The hack part here is not an understatement, and it is genuinely rather dirty. BUT, it runs in ~40-50 seconds, works the same for coverage, and can just generally be ignored as an abstraction layer.
As a downside, this makes error messages way more cryptic, but for a 20x performance gain, it can be lived with.
Warning
If you are getting failures like "Child test left in suite", one of your test files is crashing the entire process, leaving all other tests just dangling.