How to build a unit testing library from scratch?
summary
Builds a minimal testing library in Python that reproduces pytest features: a test runner that discovers and calls test functions with try/except and simple reporting, a raises context manager implemented via __enter__/__exit__, a parameterize decorator that loops subtests, and fixtures including yielding fixtures detected by checking for generators. Notes that pytest itself is ~130k lines with ~5,000 PRs; implements decorators, context managers, eval, generators and live-codes fixes — the demo mostly works after iterative bug fixes and prints tracebacks.
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chapters (10)
- 0:00Introduction
- 1:05Build your own library
- 3:33Reverse engineering pytest
- 4:37Building the test runner
- 8:30Expected exceptions with raises
- 11:43Parameterized test cases
- 14:54Designing fixtures
- 20:57Debugging fixtures
- 22:53Final demo and next steps
- 23:56Q&A
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