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| = Python UnitTest = | = Python Unittest = |
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| Python has a built-in test suite library. It is rudimentary, but requires no external libraries or tools. | '''`unittest`''' is a module for unit testing code. It is ''by design'' a basic and minimal tool; it was designed for use within Python and requiring no external libraries or tools. |
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| == Test Cases == | == Module == |
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| The basic implementation of a test case is as follows: | === Usage === |
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| === Setup and Teardown === | ==== Setup and Teardown ==== |
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| === Subtests === | ==== Subtests ==== |
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| === Conditional Testing === | ==== Conditional Testing ==== |
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| == Test Methods == | === Test Methods === |
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| ||`assertRaises` || ||`with self.assertRaises(e,msg=m):` || | ||`assertRaises` || ||`with self.assertRaises(e,msg=m): ...`|| |
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| == CLI Execution == | === CLI Execution === |
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| Verbosity is set with `-q` and `-v` flags. | Verbosity is set with `--quiet` (`-q`) and `--verbose` (`-v`) flags. |
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| The `discover` subcommand searches for files names as `test_*.py`. A search directory can be supplied additionally. | The `discover` subcommand searches for files names matching the pattern `test*.py`. A search directory can be optionally supplied using `--start-directory` (`-s`). An alternate pattern can be optionally supplied using `--pattern` (`-p`). |
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| $ python -m unittest discover -s tests/ | $ python -m unittest discover -s tests/ -v |
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---- == Writing Unit Tests == === Bad File Inputs === To create a file with a bad encoding, try: {{{ def write_bad_file(fn): with open(fn, 'w') as f: f.write('fooß'.encode('utf-8')) f.write('barß'.encode('cp1252')) }}} ---- == See also == [[https://docs.python.org/3/library/unittest.html|Python unittest module documentation]] |
Python Unittest
unittest is a module for unit testing code. It is by design a basic and minimal tool; it was designed for use within Python and requiring no external libraries or tools.
Contents
Module
Usage
import unittest
class Test1(unittest.TestCase):
"""This is a class docstring."""
def test_1(self):
#This will print "test_1 (__main__.Test1) ... ok"
return
def test_2(self):
#This will print "test_1 (__main__.Test1) ... FAIL"
self.fail()
def test_3(self):
#This will print "test_3 (__main__.Test1) ... ERROR"
raise AttributeError
@u.skip('foo bar')
def test_4(self):
#This will print "test_3 (__main__.Test1) ... skipped 'foo bar'"
return
if __name__ == '__main__':
unittest.main()Any methods with a docstring print both the method's name and the docstring.
All failures or errors print tracebacks, the only difference being the label ('FAIL' or 'ERROR').
Setup and Teardown
The most common reason for grouping a set of tests into a test case is shared objects. These can be generated using the TestCase.setUp() method. (A tearDown() method is also available if needed.)
class TestWidget(unittest.TestCase):
def setUp(self):
self.widget = Widget('The widget')\
def tearDown(self):
self.widget.dispose()
Subtests
Sometimes a test needs to be run iteratively, as to test multiple possible inputs. Rather than requiring redundant coding, the subtests context will provide this functionality.
class TestEven(unittest.TestCase):
def test_1(self):
for i in range(0, 6):
with self.subTest(i=i):
self.assertEqual(i % 2, 0)The i=i may seem redundant, but it will cause the subtest's value of i to print on execution.
Conditional Testing
Tests can be skipped conditionally. This can be used to prevent trivial test failures.
class TestVersion(unittest.TestCase):
@unittest.skipIf(mylib.__version__ < (1, 3))
def test_1(self):
return
Test Methods
Method |
Equivalent to... |
Usage |
assertEqual |
a == b |
self.assertEqual(a,b,msg=m) |
assertNotEqual |
a != b |
self.assertNotEqual(a,b,msg=m) |
assertGreater |
a > b |
self.assertGreater(a,b,msg=m) |
assertGreaterEqual |
a >= b |
self.assertGreaterEqual(a,b,msg=m) |
assertLesser |
a < b |
self.assertLesser(a,b,msg=m) |
assertLesserEqual |
a <= b |
self.assertLesserEqual(a,b,msg=m) |
assertTrue |
bool(a) == True |
self.assertTrue(a,msg=m) |
assertFalse |
bool(a) == False |
self.assertFalse(a,msg=m) |
assertIs |
a is b |
self.assertIs(a,b,msg=m) |
assertIsNot |
a is not |
self.assertIsNot(a,b,msg=m) |
assertIsNone |
a is None |
self.assertIsNone(a,b,msg=m) |
assertIsNotNone |
a is not None |
self.assertIsNotNone(a,b,msg=m) |
assertIn |
a in b |
self.assertIn(a,b,msg=m) |
assertNotIn |
a not in b |
self.assertNotIn(a,b,msg=m) |
assertRegex |
re.search(b,a) |
self.assertRegex(a,b) |
assertNotRegex |
not re.search(b,a) |
self.assertNotRegex(a,b) |
assertIsInstance |
isinstance(a,b) |
self.assertIsInstance(a,b,msg=m) |
assertIsNotInstance |
not isinstance(a,b) |
self.assertIsNotInstance(a,b,msg=m) |
assertRaises |
|
with self.assertRaises(e,msg=m): ... |
CLI Execution
Verbosity is set with --quiet (-q) and --verbose (-v) flags.
The discover subcommand searches for files names matching the pattern test*.py. A search directory can be optionally supplied using --start-directory (-s). An alternate pattern can be optionally supplied using --pattern (-p).
$ python -m unittest discover -s tests/ -v
Writing Unit Tests
Bad File Inputs
To create a file with a bad encoding, try:
def write_bad_file(fn):
with open(fn, 'w') as f:
f.write('fooß'.encode('utf-8'))
f.write('barß'.encode('cp1252'))
See also
Python unittest module documentation