Support for tests created with functools.partial

Fix #811

_pytest/python.py

@@ -18,10 +18,19 @@ callable = py.builtin.callable
 # used to work around a python2 exception info leak
 exc_clear = getattr(sys, 'exc_clear', lambda: None)
 
-def getfslineno(obj):
+def get_real_func(obj):
-    # xxx let decorators etc specify a sane ordering
+    """gets the real function object of the (possibly) wrapped object by
+    functools.wraps or functools.partial.
+    """
     while hasattr(obj, "__wrapped__"):
         obj = obj.__wrapped__
+    if isinstance(obj, py.std.functools.partial):
+        obj = obj.func
+    return obj
+
+def getfslineno(obj):
+    # xxx let decorators etc specify a sane ordering
+    obj = get_real_func(obj)
     if hasattr(obj, 'place_as'):
         obj = obj.place_as
     fslineno = py.code.getfslineno(obj)
@@ -594,7 +603,10 @@ class FunctionMixin(PyobjMixin):
 
     def _prunetraceback(self, excinfo):
         if hasattr(self, '_obj') and not self.config.option.fulltrace:
-            code = py.code.Code(self.obj)
+            if isinstance(self.obj, py.std.functools.partial):
+                code = py.code.Code(self.obj.func)
+            else:
+                code = py.code.Code(self.obj)
             path, firstlineno = code.path, code.firstlineno
             traceback = excinfo.traceback
             ntraceback = traceback.cut(path=path, firstlineno=firstlineno)
@@ -1537,7 +1549,7 @@ class FixtureLookupError(LookupError):
         for function in stack:
             fspath, lineno = getfslineno(function)
             try:
-                lines, _ = inspect.getsourcelines(function)
+                lines, _ = inspect.getsourcelines(get_real_func(function))
             except IOError:
                 error_msg = "file %s, line %s: source code not available"
                 addline(error_msg % (fspath, lineno+1))
@@ -1937,7 +1949,15 @@ def getfuncargnames(function, startindex=None):
     if realfunction != function:
         startindex += num_mock_patch_args(function)
         function = realfunction
-    argnames = inspect.getargs(py.code.getrawcode(function))[0]
+    if isinstance(function, py.std.functools.partial):
+        argnames = inspect.getargs(py.code.getrawcode(function.func))[0]
+        partial = function
+        argnames = argnames[len(partial.args):]
+        if partial.keywords:
+            for kw in partial.keywords:
+                argnames.remove(kw)
+    else:
+        argnames = inspect.getargs(py.code.getrawcode(function))[0]
     defaults = getattr(function, 'func_defaults',
                        getattr(function, '__defaults__', None)) or ()
     numdefaults = len(defaults)

testing/python/collect.py

@@ -851,3 +851,47 @@ def test_unorderable_types(testdir):
     result = testdir.runpytest()
     assert "TypeError" not in result.stdout.str()
     assert result.ret == 0
+
+
+def test_collect_functools_partial(testdir):
+    """
+    Test that collection of functools.partial object works, and arguments
+    to the wrapped functions are dealt correctly (see #811).
+    """
+    testdir.makepyfile("""
+        import functools
+        import pytest
+
+        @pytest.fixture
+        def fix1():
+            return 'fix1'
+
+        @pytest.fixture
+        def fix2():
+            return 'fix2'
+
+        def check1(i, fix1):
+            assert i == 2
+            assert fix1 == 'fix1'
+
+        def check2(fix1, i):
+            assert i == 2
+            assert fix1 == 'fix1'
+
+        def check3(fix1, i, fix2):
+            assert i == 2
+            assert fix1 == 'fix1'
+            assert fix2 == 'fix2'
+
+        test_ok_1 = functools.partial(check1, i=2)
+        test_ok_2 = functools.partial(check1, i=2, fix1='fix1')
+        test_ok_3 = functools.partial(check1, 2)
+        test_ok_4 = functools.partial(check2, i=2)
+        test_ok_5 = functools.partial(check3, i=2)
+        test_ok_6 = functools.partial(check3, i=2, fix1='fix1')
+
+        test_fail_1 = functools.partial(check2, 2)
+        test_fail_2 = functools.partial(check3, 2)
+    """)
+    result = testdir.inline_run()
+    result.assertoutcome(passed=6, failed=2)