Python - How To Write Pytest

Run Pytest

• Run a specific test file pytest path/to/test_file.py
• Run a test in it: pytest path/to/test_file.py::test_function_name

Assert

• For integer assertions:

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assert (1==1)

• For float assertions:

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import pytest
1.0==pytest.approx(1.0)

• For numpy array assertions:

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import numpy as np
array1 = np.array([1, 2, 3])
array2 = np.array([1, 2, 3])
np.testing.assert_allclose(array1, array2)

Using VSCode Debugger With Pytest

1. ctrl+shift+p choose debug tests in the current file or debug all tests (if you want to debug all tests under a configured directory)
2. In my debugger, I found that I have to manually set a breakpoint before the failure point in Pytest. (I might miss an easier route to get around this)

3. At the failed test, right click, and choose debug test

4. pytest -s <my_test.py> seems to be executing all test modules in the current directory: this will be enforced in a pyproject.toml environment.

Test Fixture

The boiler plate is:

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import pytest
@pytest.fixture
def basic_config():
    return {
        "batch_size": 2,
    }
def test_og_positional_encoder(basic_config):
    batch_size = basic_config["batch_size"]
    ...

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