Summary
When I joined Graphite, there were almost no tests in the entire codebase. The dirtier the tests, the harder they are to change. The more tangled the test code, the more likely it is that you will spend more time cramming new tests into the suite.
The mergePr method is used to test whether a PR can be merged with another PR. The code has a lot of boilerplate and is hard to read. I’ve now refactored it to separate out the logic from the side effects. This makes it easier to understand and test.
The Graphite team has been working on improving the way we test PRs. One way to do this is to use a domain-specific language. Another way is to change the way the test is written. We hope this article will help you with your own tests.
Consider the following set of checks which assert that an array contains two entries, PR #42 and PR #500. If the entries array returns three items instead of the expected two, the test will fail. An engineer would likely start by modifying the test to then output the list of returned entries.
