Jev Kuznetsov
63 lines
1.3 KiB
Markdown
63 lines
1.3 KiB
Markdown
# Testing
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Verify behavior automatically so you can change code with confidence.
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## Tools by Language
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| Language | Recommended | Alternatives |
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|---|---|---|
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| Python | `pytest` | unittest, hypothesis |
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| JavaScript/TS | `vitest` | jest, mocha |
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| Go | `testing` (stdlib) | testify |
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| C++ | `googletest` | catch2, doctest |
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## Python — `pytest`
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```bash
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pytest # run all tests
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pytest -x # stop on first failure
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pytest -k "test_login" # run matching tests
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pytest --cov=src # with coverage
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```
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Minimal test:
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```python
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def add(a: int, b: int) -> int:
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return a + b
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def test_add():
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assert add(2, 3) == 5
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```
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Configure in `pyproject.toml`:
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```toml
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[tool.pytest.ini_options]
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testpaths = ["tests"]
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addopts = "-ra -q"
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```
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## JavaScript — `vitest`
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```bash
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vitest run # run once
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vitest # watch mode
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vitest --coverage
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```
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## Go
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```bash
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go test ./... # run all tests
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go test -race ./... # with race detector
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go test -cover ./...
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```
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## Key Principles
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- Test behavior, not implementation — tests that break on refactors aren't useful
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- Fast tests get run; slow tests get skipped
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- Don't mock more than necessary — integration tests catch what unit tests miss
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- Add a test when you fix a bug; the bug was a missing test
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