repeated_test
lets you write tests that apply the same function to
many sets of parameters.
For instance:
from repeated_test import Fixtures
class MyFixtures(Fixtures):
def _test(self, expected, *terms):
self.assertEqual(expected, sum(terms))
a = 10, 5, 5
b = 15, 7, 8
c = 42, 1, 1
The result is unittest-compatible, and provides useful context in the traceback in case of errors:
$ python -m unittest my_tests
..F
======================================================================
FAIL: test_c (my_tests.MyFixtures)
----------------------------------------------------------------------
Traceback (most recent call last):
File "my_tests.py", line 9, in MyFixtures
c = 42, 1, 1
File "my_tests.py", line 5, in _test
self.assertEqual(expected, sum(terms))
AssertionError: 42 != 2
----------------------------------------------------------------------
Ran 3 tests in 0.002s
FAILED (failures=1)
You can install it using:
$ pip install --user repeated_test
You can get help in the gitter.im chatroom.
If you find any issues or have any requests, use GitHub Issues.
Python's unittest modules helps in performing various forms of automated testing.
One writes a class deriving from unittest.TestCase and adds various test_xyz
methods.
Test runners run these tests, keeping count of successful and failed tests,
and produces a trace with the causes of these failures.
Sometimes it makes sense to have one test be carried out for a large amount of different inputs. This module aims to provide an efficient way to do this.
It allows you to write fixtures (inputs) as plain members of a class, and bind a test function to them. This test function is called for each fixture as you will see below. The produced class is a unittest.TestCase subclass, so it is compatible with unittest and other unittest-compatible test runners.
In order to produce a unittest.TestCase, repeated_test
requires you to:
- Subclass
repeated_test.Fixtures
- Write a
_test
method that takes a few parameters, making use of any unittest.TestCase method it needs - Assign fixtures directly in the class body, which are then unpacked as
arguments to the
_test
method (as in_test(*args)
)
You can use any unittest.TestCase methods in your test function, such as assertEqual()
and so forth.
from repeated_test import Fixtures
class MyFixtures(Fixtures):
def _test(self, arg1, arg2, arg3):
self.assertEqual(..., ...)
Ps = 'p1', 'p2', 'p3'
# _test(*Ps) will be called, ie. _test('p1', p2', 'p3')
Qs = 'q1', 'q2', 'q3'
# _test(*Qs) will be called, ie. _test('q1', q2', 'q3')
Make sure that your fixture tuples provide the correct amount of arguments
for your _test
method, unless it has an *args
parameter.
You can run a repeated_test
test case like any other unittest.TestCase class:
python -m unittest
python -m unittest my_test_module
python -m unittest my_test_module.MyFixtures
# To refer to an individual test, prefix the name of the fixture with "test_"
python -m unittest my_test_module.MyFixtures.test_Ps
Learn more in the official unittest docs.
You can also use a unittest-compatible test runer, like pytest:
python -m pytest
python -m pytest my_test_module.py
python -m pytest my_test_module.py -k MyFixtures
python -m pytest my_test_module.py -k test_Ps
python -m pytest my_test_module.py::MyFixtures::test_Ps
Learn more in the official pytest docs
You can pass in keyword arguments using repeated_test.options
:
import sys
from repeated_test import Fixtures, options
class MyFixtures(Fixtures):
def _test(self, arg1, arg2, *, min_version=None, max_version=None):
...
not_using_versions = "abc", "abc"
# -> _test("abc", "abc")
using_max_version = "abc", "abc", options(max_version=(3, 9))
# -> _test("abc", "abc", max_version=(3, 9))
using_both_versions = "abc", "abc", options(min_version=(3, 8), max_version=(3, 9))
# -> _test("abc", "abc", min_version=(3, 8), max_version=(3, 9))
using_both_versions_2 = "abc", "abc", options(min_version=(3, 8)), options(max_version=(3, 9))
# Same, but by specifying options separately
This can be useful if you have multiple options that are only used some of the time.
If you are re-using the same keyword arguments across multiple tests, there are several ways to do so:
- Using
@repeated_test.with_options(...)
lets you specify options for every fixture within a class. - Using
with repeated_test.options(...)
lets you specify options for every fixture within thewith
block. - You can continue using
options()
on individual fixtures, and override values provided by surrounding code. - You can use
repeated_test.skip_option
to stop supplying any argument. The argument won't be supplied to the function, which is useful for using a default value, or for removing common options from a class whose test function doesn't handle
from repeated_test import Fixtures, options, with_options
@with_options(kwarg1="value from decorator")
class MyFixtures(Fixtures):
def _test(self, arg1, arg2, *, kwarg1, kwarg2="default"):
...
using_provided_values = "arg1", "arg2"
# -> _test("arg1", "arg2", kwarg1="value from decorator", kwarg2="default")
overriding_provided_values = "arg1", "arg2", options(kwarg1="kwarg1", kwarg2="kwarg2")
# -> _test("arg1", "arg2", kwarg1="kwarg1", kwarg2="kwarg2")
with options(kwarg1="value from context manager"):
using_value_from_context_manager = "arg1", "arg2"
# -> _test("arg1", "arg2", kwarg1="value from context manager", kwarg2="default")
overriding_value_from_context_manager = "arg1", "arg2", options(kwarg1="kwarg1")
# -> _test("arg1", "arg2", kwarg1="kwarg1", kwarg2="default")
with options(kwarg2="value from context manager"):
removing_value = "arg1", "arg2"
# -> _test("arg1", "arg2", kwarg1="value from decorator", kwarg2="value from context manager")
removing_value = "arg1", "arg2", options(kwarg2=skip_option)
# -> _test("arg1", "arg2", kwarg1="value from decorator", kwarg2="default")
You can also use @with_options_matrix
to provide multiple values for a keyword parameter.
repeated_test
will run every combination
except for parameters that are overridden.
from repeated_test import Fixtures, options, with_options_matrix
@with_options_matrix(
spam=["spam1", "spam2"],
ham=["ham1", "ham2"],
)
class MyFixtures(Fixtures):
def _test(self, arg1, arg2, *, spam, ham):
...
using_provided_values = "arg1", "arg2"
# -> _test("arg1", "arg2", spam="spam1", ham="ham1")
# -> _test("arg1", "arg2", spam="spam1", ham="ham2")
# -> _test("arg1", "arg2", spam="spam2", ham="ham1")
# -> _test("arg1", "arg2", spam="spam2", ham="ham2")
with options(spam="spam"):
overriding_one_value = "arg1", "arg2"
# -> _test("arg1", "arg2", spam="spam", ham="ham1")
# -> _test("arg1", "arg2", spam="spam", ham="ham2")
repeated_test
will report each combination using unittest's subtests feature.
pytest does not have this feature built-in, but the pytest-subtests plugin adds support.
======================================================================
FAIL: test_overriding_one_value (example_options._test) (ham='ham1')
----------------------------------------------------------------------
Traceback (most recent call last):
File "/home/myself/repeated_test/example_options.py", line 41, in MyFixtures
overriding_one_value = "arg1", "arg2"
File "/home/myself/repeated_test/example_options.py", line 32, in _test
self.fail("example failure")
AssertionError: example failure
======================================================================
FAIL: test_overriding_one_value (example_options._test) (ham='ham2')
----------------------------------------------------------------------
Traceback (most recent call last):
File "/home/myself/repeated_test/example_options.py", line 41, in MyFixtures
overriding_one_value = "arg1", "arg2"
File "/home/myself/repeated_test/example_options.py", line 32, in _test
self.fail("example failure")
AssertionError: example failure
You can use @evaluated
to make
a function that can be inserted in a test case tuple.
When running the test,
the function will be called,
and the result will be spliced into the test case tuple:
from repeated_test import Fixtures, evaluated
class EvaluatedFixtures(Fixtures):
def _test(self, a, b, c):
pass
@evaluated
def fully_evaluated(self):
return (1 + 1, 2, 3)
# -> _test(2, 2, 3)
@evaluated
def _helper():
return (1 + 2, 3)
partly_evaluated = _helper(), 4
# -> _test(3, 3, 4)
The wrapped function must always return a tuple.
The wrapped function will also receive options as keyword arguments:
from repeated_test import Fixtures, evaluated, with_options_matrix
@with_options_matrix(
option=[
"option 1",
"option 2",
],
)
class EvaluatedFixturesWithOptions(Fixtures):
def _test(self, a, *, option):
pass
@evaluated
def _helper(arg, *, option):
return (f"{arg}-{option}",)
using_option_in_evaluated = _helper("arg")
# -> _test("arg-option 1", option="option 1")
# -> _test("arg-option 2", option="option 2")
When using with_options_matrix
,
sometimes the repr generated by those options is difficult to read.
This can be the case with functions,
which can end up showing as something like
<function myfunc at 0x7f9f5e506280>
.
You can use NamedAlternative
to give them a name:
from repeated_test import NamedAlternative
value1 = NamedAlternative("name for value1", "value1")
@NamedAlternative("name for func1")
def func1():
pass
You may name your test tuples however you like, though they may not start with
test_
or _
. They are copied to the resulting unittest.TestCase class, and test
methods are created for them. Their name is that of the tuple, prefixed with
test_
.
Members starting with test_
or _
are directly copied over to the
resulting unittest.TestCase class, without being treated as fixtures. You can use this to
insert regular tests amongst your fixtures, or constants that you do not wish
to be treated as tests:
from repeated_test import Fixtures
class MyFixtures(Fixtures):
def _test(self, arg1, arg2, arg3):
self.assertEqual(..., ...)
def test_other(self):
self.assertEqual(3, 1+2)
_spam = 'spam, bacon and eggs'
# _spam won't be treated as a fixture, so _test(*_spam) won't be called
ham = _spam, _spam, _spam
You may even call the test function using self._test(...)
if necessary.
You can apply a fixtures class to a different test function using its
with_test
method:
class MyFixtures(Fixtures):
_test = None
...
@MyFixtures.with_test
def other_test(self, arg1, arg2, arg3):
self.assertEqual(..., ...)
While the function appears out of any class, it will be used as a method of
the resulting unittest.TestCase class, so keep in mind that it takes a self
parameter.
You can reuse a fixture class however many times you like.
If you specify a test function this way, you can set _test = None
in your fixtures definition. However, it will not be discovered by unittest,
so regular test methods won't be run.
Omitting _test
completely raises an error in order to prevent accidentally
disabling your tests.
It can be fairly impractical to use functions in your fixture tuples in this
scheme. If your fixture tuple is meant to have one function in it, you can
use the tup
decorator:
from repeated_test import Fixtures, tup
class my_tests(Fixtures):
def _test(self, func, arg1, arg2):
self.assertEqual(..., ...)
@tup('arg1', 'arg2')
def ham():
pass
# equivalent to
def _ham():
pass
ham = _ham, 'arg1', 'arg2'
You can replace unittest.TestCase with another class using WithTestClass(cls)
.
For instance, if you wish to use unittest2
:
import unittest2
from repeated_test import WithTestClass
class my_tests(WithTestClass(unittest2.TestCase)):
...