idow09/testing101

A sample code for the testing_101 lecture

• Is 8 seconds considered a long time for a test to run?
  • Whatsapp analogy (8 seconds is a long time for a message to be sent right? That's the kind of feedback we're looking for)
  • Running tests locally vs CI
• Simple example
  • pytest.mark.parametrized
  • with pytest.raises(Exception)
• Frameworks testing utilities (pandas, asyncio, etc.)
• Fragile e2e tests (example: "tests/test_histogram_reporter.py")
• Single Responsibility Principle: Extract dependencies, use test doubles (example: "tests/test_histogram_reporter_srp.py")
  • This test didn't fail when refactoring from per-word to per-char.
  • Tests eliminate fear of change.
• Patching make it easier to test (example: "tests/test_histogram_reporter_srp_patch.py")
  • No need to use explicit dependency injection (but you probably should nonetheless!)
  • Where to patch?
    • https://docs.python.org/3/library/unittest.mock.html#where-to-patch
• Surprise from this morning! (example: "tests/test_histogram_reporter_codium.py")