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jbranchaud
28 lines
1.1 KiB
Markdown
28 lines
1.1 KiB
Markdown
# Start The Debugger When A Test Errors
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While working on [some
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tests](https://github.com/jbranchaud/build-an-llm-from-scratch/blob/main/tests/chapter_02/test_bpe_tokenizer.py)
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for my Byte Pair Encoding tokenizer, I was running into an unexpected test
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failure. To better understand what was going on, I needed to inspect the state
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of the program around the time the code raised an exception.
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Instead of needing to manually set a breakpoint at the correct spot to begin
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debugging, I can run the test with the Pytest-supported `--pdb` flag. That's
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short for _python debugger_.
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> Start the interactive Python debugger on errors or KeyboardInterrupt
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What this does during a test run is opens you up to the interactive Python
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debugger at the exact moment an exception is raised. This gives you the ability
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to inspect values of the program state at that point in execution which could
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help inform the needed fix.
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```bash
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uv run pytest -vv --pdb -k "test_train_bpe"
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```
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There I am running a specific test that matches against `-k "test_train_bpe"`
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and the python debugger will start up if there is an error.
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See `uv run pytest --help` for more details.
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