Pytest

Install #

pip install pytest

Rules #

  • Name all testing files with[ref] test_*.py or *_test.py.
  • Name all "be tested" functions with def test_*.

Executing #

pytest test_sample.py
pytest -q test_sample.py # quiet mode
# ignore all files in folder statistics
pytest -k "not statistics"

Simple #

# test_sample.py
def func(x):
return x + 1

def test_answer():
assert func(3) == 5
# then run
pytest test_sample.py

With parameters #

# test_sample.py
@pytest.mark.parametrize(
"input, param_1, param_2, result",
[
(df_1, 'date', np.mean, df_result_1),
(df_2, 'date', np.mean, df_result_2),
]
)

def test_run(input, param_1, param_2, result):
spts = SPTS(param_1=param_1, param_2=param_2)
df_tmp = spts.run(df)
assert isinstance(df_tmp, pd.DataFrame)
assert df_tmp.equals(result)
# To get all combinations
@pytest.mark.parametrize("x", [0, 1])
@pytest.mark.parametrize("y", [2, 3])

def test_foo(x, y):
pass

# Then the arguments set to `x=0/y=2`,
# `x=1/y=2`, `x=0/y=3`, and `x=1/y=3`.

Note that, @pytest.mark.parametrize must be placed right before the function who uses it. Otherwise, there is an error fixture not found.

# ERROR
@pytest.mark.parametrize("x", [0, 1])
def test_foo(x):
pass

def test_bar(x):
pass
# FIX
@pytest.mark.parametrize("x", [0, 1])
def test_foo(x):
pass

@pytest.fixture
def test_bar(x):
pass

Custom marker #

Run tests who have a specific marker.[ref]

@pytest.mark.marker_1
def test_func1():
pass

@pytest.mark.marker_2
def test_func2():
pass

@pytest.mark.marker_1
def test_func3():
pass
# with tag 'marker_1'
pytest -v -m marker_1

# except tag 'marker_1'
pytest -v -m 'not marker_1'

Errors #

# ImportError: No module named atomicwrites
python -m pytest
python3 -m pytest

Ignore warning #

👉 Main reference.

# eg: RuntimeWarning: numpy.ufunc size changed,
@pytest.mark.filterwarnings('ignore::RuntimeWarning')
@pytest.mark.level_1
def test_load(df_test, report):

References #

This is a draft note.