Enhetstestning

Mjukvaruutvecklingsprinciper i Python

Adam Spannbauer

Machine Learning Engineer at Eastman

Varför testa?

Bekräfta att koden fungerar som avsett
Säkerställ att ändringar i en funktion inte bryter en annan
Skydda mot ändringar i ett beroende

Testning i Python

doctest
pytest

pytest-logotyp

Använda doctest

def square(x):
    """Square the number x

    :param x: number to square
    :return: x squared

    >>> square(3)
    9
    """
    return x ** 3



import doctest
doctest.testmod()

Failed example:
    square(3)
Expected:
    9
Got:
    27

pytest-struktur

Teststruktur

pytest-struktur

Teststruktur

Skriva enhetstester

arbetar i workdir/tests/test_document.py

from text_analyzer import Document


# Test tokens attribute on Document object
def test_document_tokens():
    doc = Document('a e i o u')

    assert doc.tokens == ['a', 'e', 'i', 'o', 'u']


# Test edge case of blank document
def test_document_empty():
    doc = Document('')

    assert doc.tokens == []
    assert doc.word_counts == Counter()

Skriva enhetstester

# Create 2 identical Document objects
doc_a = Document('a e i o u')
doc_b = Document('a e i o u')

# Check if objects are ==
print(doc_a == doc_b)

# Check if attributes are ==
print(doc_a.tokens == doc_b.tokens)
print(doc_a.word_counts == doc_b.word_counts)

False

True
True

Köra pytest

arbetar med terminal

datacamp@server:~/work_dir $ pytest

collected 2 items

tests/test_document.py ..                     [100%]

========== 2 passed in 0.61 seconds ==========

Köra pytest

arbetar med terminal

datacamp@server:~/work_dir $ pytest tests/test_document.py

collected 2 items

tests/test_document.py ..                     [100%]

========== 2 passed in 0.61 seconds ==========

Misslyckade tester

arbetar med terminal

datacamp@server:~/work_dir $ pytest

collected 2 items

tests/test_document.py F.

============== FAILURES ==============
________ test_document_tokens ________

def test_document_tokens(): doc = Document('a e i o u')

assert doc.tokens == ['a', 'e', 'i', 'o']
E AssertionError: assert ['a', 'e', 'i', 'o', 'u'] == ['a', 'e', 'i', 'o']
E Left contains more items, first extra item: 'u'
E Use -v to get the full diff

tests/test_document.py:7: AssertionError
====== 1 failed in 0.57 seconds ======

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Mjukvaruutvecklingsprinciper i Python