Removed dependency on @mock.patch('test_core...')

The construct was working fine if starting in the tests directory but
the module would not be found in the context of python setup.py tests
when the current directory is one level up.

tests/test_core.py

@@ -404,6 +404,8 @@ def other():
     )
 
     class FakeProject(scm.Project):
+        """Fake project with pre-determined values for the download return values."""
+
         def download(self, data: pd.DataFrame) -> scm.DownloadResult:
             pass
 
@@ -434,8 +436,9 @@ def setUp(self):
     def get_complexity(self):
         """Factor retrieval of complexity"""
         project = self.FakeProject()
-        with mock.patch(
-            "test_core.GetComplexityTestCase.FakeProject.download",
+        with mock.patch.object(
+            self.FakeProject,
+            "download",
             autospec=True,
             side_effect=[
                 scm.DownloadResult("r1", "f.py", self.file_content_1),
@@ -460,23 +463,26 @@ def test_lizard_analyze(self, _):
         self.assertEqual(4, actual.nloc)
         self.assertEqual(2.0, actual.average_cyclomatic_complexity)
 
-    @mock.patch(
-        "test_core.GetComplexityTestCase.FakeProject.download",
-        autospec=True,
-        return_value=scm.DownloadResult(1, "f.py", ""),
-    )
-    def test_handles_no_function(self, _):
+    def test_handles_no_function(self):
         """Handles files with no function well."""
-        actual = (
-            cm.get_complexity(self.log, self.FakeProject())
-            .reset_index()
-            .pipe(pd.Series.astype, "string")
-        )
         columns = (
             "function".split()
             + cm.core._lizard_fields
             + "file_tokens file_nloc".split()
         )
+        project = self.FakeProject()
+        with mock.patch.object(
+            self.FakeProject,
+            "download",
+            autospec=True,
+            return_value=scm.DownloadResult(1, "f.py", ""),
+        ) as download:
+            actual = (
+                cm.get_complexity(self.log, project)
+                .reset_index()
+                .pipe(pd.Series.astype, "string")
+            )
+            download.assert_called_with(project, self.log)
         expected = pd.DataFrame(data={k: [] for k in columns}, dtype="string")
         self.assertEqual(expected, actual)
 
@@ -487,16 +493,14 @@ def test_analysis_empty_input_return_empty_output(self, _):
         actual = cm.get_complexity(self.log, self.FakeProject())
         self.assertTrue(actual.empty)
 
-    @mock.patch(
-        "test_core.GetComplexityTestCase.FakeProject.download",
-        autospec=True,
-        return_value=scm.DownloadResult(1, "/", ""),
-    )
-    def test_use_default_download(self, download):
+    def test_use_default_download(self):
         """When the context.downlad_funcc is defined, use it."""
         project = self.FakeProject()
-        _ = cm.get_complexity(self.log, project)
-        download.assert_called_with(project, self.log)
+        with mock.patch.object(
+            self.FakeProject, "download", return_value=scm.DownloadResult(1, "/", "")
+        ) as download:
+            _ = cm.get_complexity(self.log, project)
+            download.assert_called_with(self.log)
 
     def test_analysis_with_groupby_svn_download(self):
         """Check interface with svn."""