Allow custom fixture names for fixtures

When defining a fixture in the same module as where it is used, the
function argument shadows the fixture name, which a) annoys pylint and
b) can lead to bugs where you forget pull a fixture into a test method.

This allows one to define fixtures with a custom name override,
bypassing that problem.

Author: novas0x2a

_pytest/python.py

@@ -114,12 +114,13 @@ def safe_getattr(object, name, default):
 
 class FixtureFunctionMarker:
     def __init__(self, scope, params,
-                 autouse=False, yieldctx=False, ids=None):
+                 autouse=False, yieldctx=False, ids=None, name=None):
         self.scope = scope
         self.params = params
         self.autouse = autouse
         self.yieldctx = yieldctx
         self.ids = ids
+        self.name = name
 
     def __call__(self, function):
         if isclass(function):
@@ -129,7 +130,7 @@ def __call__(self, function):
         return function
 
 
-def fixture(scope="function", params=None, autouse=False, ids=None):
+def fixture(scope="function", params=None, autouse=False, ids=None, name=None):
     """ (return a) decorator to mark a fixture factory function.
 
     This decorator can be used (with or or without parameters) to define
@@ -159,10 +160,10 @@ def fixture(scope="function", params=None, autouse=False, ids=None):
     if callable(scope) and params is None and autouse == False:
         # direct decoration
         return FixtureFunctionMarker(
-                "function", params, autouse)(scope)
+                "function", params, autouse, name=name)(scope)
     if params is not None and not isinstance(params, (list, tuple)):
         params = list(params)
-    return FixtureFunctionMarker(scope, params, autouse, ids=ids)
+    return FixtureFunctionMarker(scope, params, autouse, ids=ids, name=name)
 
 def yield_fixture(scope="function", params=None, autouse=False, ids=None):
     """ (return a) decorator to mark a yield-fixture factory function
@@ -1989,6 +1990,8 @@ def parsefactories(self, node_or_obj, nodeid=NOTSET, unittest=False):
                 # fixture attribute
                 continue
             else:
+                if marker.name:
+                    name = marker.name
                 assert not name.startswith(self._argprefix)
             fixturedef = FixtureDef(self, nodeid, name, obj,
                                     marker.scope, marker.params,

testing/python/fixture.py

@@ -2691,3 +2691,14 @@ def test_1(arg1):
             *def arg1*
         """)
 
+    def test_custom_name(self, testdir):
+        testdir.makepyfile("""
+            import pytest
+            @pytest.fixture(name='meow')
+            def arg1():
+                return 'mew'
+            def test_1(meow):
+                print(meow)
+        """)
+        result = testdir.runpytest("-s")
+        result.stdout.fnmatch_lines("*mew*")