Now with 100% less Python 3 incompatibility!
Nose. It's got test generators. But they kind of suck:
- They often require a second function
- They make it difficult to separate the data from the test
- They don't work with subclases of
unittest.TestCase
kwargs
? Whatkwargs
?
But nose-parameterized
fixes that:
# test_math.py
from nose.tools import assert_equal
from nose_parameterized import parameterized
import unittest
import math
@parameterized([
(2, 2, 4),
(2, 3, 8),
(1, 9, 1),
(0, 9, 0),
])
def test_pow(base, exponent, expected):
assert_equal(math.pow(base, exponent), expected)
class TestMathUnitTest(unittest.TestCase):
@parameterized.expand([
("negative", -1.5, -2.0),
("integer", 1, 1.0),
("large fraction", 1.6, 1),
])
def test_floor(self, name, input, expected):
assert_equal(math.floor(input), expected)
$ nosetests -v test_math.py
test_math.test_pow(2, 2, 4) ... ok
test_math.test_pow(2, 3, 8) ... ok
test_math.test_pow(1, 9, 1) ... ok
test_math.test_pow(0, 9, 0) ... ok
test_floor_0_negative (test_math.TestMathUnitTest) ... ok
test_floor_1_integer (test_math.TestMathUnitTest) ... ok
test_floor_2_large_fraction (test_math.TestMathUnitTest) ... ok
----------------------------------------------------------------------
Ran 7 tests in 0.002s
OK
The @parameterized
and @parameterized.expand
decorators accept a list or iterable of tuples or param(...)
, or a callable which returns a list or iterable:
from nose_parameterized import parameterized, param
# A list of tuples
@parameterized([
(2, 3, 5),
(3, 5, 8),
])
def test_add(a, b, expected):
assert_equal(a + b, expected)
# A list of params
@parameterized([
param("10", 10),
param("10", 16, base=16),
])
def test_int(str_val, expected, base=10):
assert_equal(int(str_val, base=base), expected)
# An iterable of params
@parameterized(
param.explicit(*json.loads(line))
for line in open("testcases.jsons")
)
def test_from_json_file(...):
...
# A callable which returns a list of tuples
def load_test_cases():
return [
("test1", ),
("test2", ),
]
@parameterized(load_test_cases)
def test_from_function(name):
...
Note that, when using an iterator or a generator, Nose will read every item into memory before running any tests (as it first finds and loads every test in each test file, then executes all of them at once).
The @parameterized
decorator can be used test class methods, and standalone functions:
from nose_parameterized import parameterized
class AddTest(object):
@parameterized([
(2, 3, 5),
])
def test_add(self, a, b, expected):
assert_equal(a + b, expected)
@parameterized([
(2, 3, 5),
])
def test_add(a, b, expected):
assert_equal(a + b, expected)
And @parameterized.expand
can be used to generate test methods in situations where test generators cannot be used (for example, when the test class is a subclass of unittest.TestCase
):
import unittest
from nose_parameterized import parameterized
class AddTestCase(unittest.TestCase):
@parameterized.expand([
("2 and 3", 2, 3, 5),
("3 and 5", 2, 3, 5),
])
def test_add(self, _, a, b, expected):
assert_equal(a + b, expected)
Will create the test cases:
$ nosetests example.py
test_add_0_2_and_3 (example.AddTestCase) ... ok
test_add_1_3_and_5 (example.AddTestCase) ... ok
----------------------------------------------------------------------
Ran 2 tests in 0.001s
OK
Note that @parameterized.expand
works by creating new methods on the test class. If the first parameter is a string, that string will be added to the end of the method name. For example, the test case above will generate the methods test_add_0_2_and_3
and test_add_1_3_and_5
.
The names of the test cases generated by @parameterized.expand
can be customized using the testcase_func_name
keyword argument. The value should be a function which accepts three arguments: testcase_func
, param_num
, and params
, and it should return the name of the test case. testcase_func
will be the function to be tested, param_num
will be the index of the test case parameters in the list of parameters, and param
(an instance of param
) will be the parameters which will be used.
import unittest
from nose_parameterized import parameterized
def custom_name_func(testcase_func, param_num, param):
return "%s_%s" %(
testcase_func.__name__,
parameterized.to_safe_name("_".join(str(x) for x in param.args)),
)
class AddTestCase(unittest.TestCase):
@parameterized.expand([
(2, 3, 5),
(2, 3, 5),
], testcase_func_name=custom_name_func)
def test_add(self, a, b, expected):
assert_equal(a + b, expected)
Will create the test cases:
$ nosetests example.py
test_add_1_2_3 (example.AddTestCase) ... ok
test_add_2_3_5 (example.AddTestCase) ... ok
----------------------------------------------------------------------
Ran 2 tests in 0.001s
OK
The param(...)
helper class stores the parameters for one specific test case. It can be used to pass keyword arguments to test cases:
from nose_parameterized import parameterized, param
@parameterized([
param("10", 10),
param("10", 16, base=16),
])
def test_int(str_val, expected, base=10):
assert_equal(int(str_val, base=base), expected)