接着上一篇的内容，这里主要讲下参数化，pytest很好的支持了测试函数中变量的参数化
一、pytest的参数化
1、通过命令行来实现参数化
文档中给了一个简单的例子，
test_compute.py 的测试函数如下：
# content of test_compute.py
def test_compute(param1):
assert param1 <4
在conftest.py中添加两个函数，一个是添加参数，一个是根据参数生成测试
# content of conftest.py
def pytest_addoption(parser):
parser.addoption("--all", action="store_true",help="run all combinations")
def pytest_generate_tests(metafunc):
if 'param1' in metafunc.fixturenames:
if metafunc.config.option.all:
end = 5
else:
end = 2
metafunc.parametrize("param1", range(end)) 1 C:\Python27\python.exe E:/test/testwith.py
2 __enter__
3 test
4 __exit__
通过在命令行添加--all的option来实现参数化，执行py.test -q test_compute.py 会发现只有2个case，而执行 py.test -q test_compute.py --all 会执行5个case
2、不同test IDs的参数化
在pytest会为每一组参数集合建立一个ID，可以试用-k来select匹配的名字子串，所以可以为不同的测试数据建立ID来区分不同的case，这个是经常使用的变量参数化，注意pytest.mark.parametrize（）的括号中的顺序，(变量名称，对应的(参数化元组)的数组，ID的数组) , 这样很好的解决了代码重复编写，减少了维护，可以很好的实现数据与代码想分离
# content of test_time.py
import pytest
from datetime import datetime, timedelta
testdata = [
(datetime(2001, 12, 12), datetime(2001, 12, 11), timedelta(1)),
(datetime(2001, 12, 11), datetime(2001, 12, 12), timedelta(-1)),
]
@pytest.mark.parametrize("a,b,expected", testdata)
def test_timedistance_v0(a, b, expected):
diff = a - b
assert diff == expected
@pytest.mark.parametrize("a,b,expected", testdata, ids=["forward", "backward"])
def test_timedistance_v1(a, b, expected):
diff = a - b
assert diff == expected
3、重要的资源参数化，这里面给了个case，是关于db的，觉得没太多可说的，就是一个简单的工厂，上代码了
# content of conftest.py
import pytest
def pytest_generate_tests(metafunc):
if 'db' in metafunc.fixturenames:
metafunc.parametrize("db", ['d1', 'd2'], indirect=True)
class DB1:
"one database object"
class DB2:
"alternative database object"
@pytest.fixture
def db(request):
if request.param == "d1":
return DB1()
elif request.param == "d2":
return DB2()
else:
raise ValueError("invalid internal test config")
4、通过类来实现测试函数的参数化，这个还是很有意义的，自己理解下吧，没什么难度
# content of ./test_parametrize.py
import pytest
def pytest_generate_tests(metafunc):
# called once per each test function
funcarglist = metafunc.cls.params[metafunc.function.__name__]
argnames = list(funcarglist[0])
metafunc.parametrize(argnames, [[funcargs[name] for name in argnames] for funcargs in funcarglist])
class TestClass:
# a map specifying multiple argument sets for a test method
params = {
'test_equals': [dict(a=1, b=2), dict(a=3, b=3), ],
'test_zerodivision': [dict(a=1, b=0), ],
}
def test_equals(self, a, b):
assert a == b
def test_zerodivision(self, a, b):
pytest.raises(ZeroDivisionError, "a/b")
5、通过multiple fixtures来实现间接的参数化，文档中给了使用不同版本的python编译器的代码，有需求的自己看下吧
"""
module containing a parametrized tests testing cross-python
serialization via the pickle module.
"""
import py
import pytest
import _pytest._code
pythonlist = ['python2.6', 'python2.7', 'python3.3']
@pytest.fixture(params=pythonlist)
def python1(request, tmpdir):
picklefile = tmpdir.join("data.pickle")
return Python(request.param, picklefile)
@pytest.fixture(params=pythonlist)
def python2(request, python1):
return Python(request.param, python1.picklefile)
class Python:
def __init__(self, version, picklefile):
self.pythonpath = py.path.local.sysfind(version)
if not self.pythonpath:
pytest.skip("%r not found" % (version,))
self.picklefile = picklefile
def dumps(self, obj):
dumpfile = self.picklefile.dirpath("dump.py")
dumpfile.write(_pytest._code.Source("""
import pickle
f = open(%r, 'wb')
s = pickle.dump(%r, f, protocol=2)
f.close()
""" % (str(self.picklefile), obj)))
py.process.cmdexec("%s %s" % (self.pythonpath, dumpfile))
def load_and_is_true(self, expression):
loadfile = self.picklefile.dirpath("load.py")
loadfile.write(_pytest._code.Source("""
import pickle
f = open(%r, 'rb')
obj = pickle.load(f)
f.close()
res = eval(%r)
if not res:
raise SystemExit(1)
""" % (str(self.picklefile), expression)))
print (loadfile)
py.process.cmdexec("%s %s" %(self.pythonpath, loadfile))
@pytest.mark.parametrize("obj", [42, {}, {1:3},])
def test_basic_objects(python1, python2, obj):
python1.dumps(obj)
python2.load_and_is_true("obj == %s" % obj)
二、使用自定义的markers
1、自定义一个mark，如下，然后 py.test -v -m webtest 只运行标记了webtest的函数， py.test -v -m "not webtest" 来运行未标记webtest的
# content of test_server.py
import pytest
@pytest.mark.webtest
def test_send_http():
pass # perform some webtest test for your app
def test_something_quick():
pass
def test_another():
pass
class TestClass:
def test_method(self):
pass
2、还可以通过-v 指定的函数ID， py.test -v test_server.py::TestClass::test_method 来运行指定的函数
3、使用-k 来匹配名字子串， py.test -v -k http ， py.test -k "not send_http" -v
4、在pytest.ini中注册markers
# content of pytest.ini
[pytest]
markers =
webtest: mark a test as a webtest.
addopts = --pyargs
好了，就这么多吧，下面的一些关于mocking的，有时间再来写
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