99 lines
2.8 KiB
Python
99 lines
2.8 KiB
Python
"""
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convenient capturing of writes to stdout/stderror streams
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and file descriptors.
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Example Usage
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----------------------
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You can use the `capsys funcarg`_ to capture writes
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to stdout and stderr streams by using it in a test
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likes this:
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.. sourcecode:: python
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def test_myoutput(capsys):
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print "hello"
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print >>sys.stderr, "world"
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out, err = capsys.reset()
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assert out == "hello\\n"
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assert err == "world\\n"
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print "next"
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out, err = capsys.reset()
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assert out == "next\\n"
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The ``reset()`` call returns a tuple and will restart
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capturing so that you can successively check for output.
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After the test function finishes the original streams
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will be restored.
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"""
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import py
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def pytest_funcarg__capsys(request):
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"""captures writes to sys.stdout/sys.stderr and makes
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them available successively via a ``capsys.reset()`` method
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which returns a ``(out, err)`` tuple of captured strings.
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"""
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capture = Capture(py.io.StdCapture)
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request.addfinalizer(capture.finalize)
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return capture
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def pytest_funcarg__capfd(request):
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"""captures writes to file descriptors 1 and 2 and makes
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them available successively via a ``capsys.reset()`` method
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which returns a ``(out, err)`` tuple of captured strings.
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"""
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capture = Capture(py.io.StdCaptureFD)
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request.addfinalizer(capture.finalize)
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return capture
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def pytest_pyfunc_call(pyfuncitem):
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if hasattr(pyfuncitem, 'funcargs'):
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for funcarg, value in pyfuncitem.funcargs.items():
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if funcarg == "capsys" or funcarg == "capfd":
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value.reset()
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class Capture:
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_capture = None
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def __init__(self, captureclass):
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self._captureclass = captureclass
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def finalize(self):
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if self._capture:
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self._capture.reset()
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def reset(self):
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res = None
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if self._capture:
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res = self._capture.reset()
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self._capture = self._captureclass()
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return res
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class TestCapture:
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def test_std_functional(self, testdir):
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reprec = testdir.inline_runsource("""
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def test_hello(capsys):
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print 42
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out, err = capsys.reset()
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assert out.startswith("42")
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""")
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reprec.assertoutcome(passed=1)
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def test_stdfd_functional(self, testdir):
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reprec = testdir.inline_runsource("""
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def test_hello(capfd):
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import os
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os.write(1, "42")
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out, err = capfd.reset()
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assert out.startswith("42")
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""")
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reprec.assertoutcome(passed=1)
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def test_funcall_yielded_no_funcargs(self, testdir):
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reprec = testdir.inline_runsource("""
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def test_hello():
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yield lambda: None
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""")
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reprec.assertoutcome(passed=1)
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