Got testing of the generator-with-exception to work

z3c/dependencychecker/tests/test_modules_docfiles.py

@@ -1,5 +1,4 @@
 from pathlib import Path
-from unittest import mock
 
 from z3c.dependencychecker.modules import DocFiles
 from z3c.dependencychecker.tests.utils import write_source_file_at
@@ -84,14 +83,19 @@ def test_create_from_files_deep_nested_txt(minimal_structure):
 
 def test_unicode_decode_error():
     docfiles = DocFiles("somewhere", "some_file")
-    docfiles._scan = mock.MagicMock
-    # Thanks to
-    # https://gehrcke.de/2015/12/how-to-raise-unicodedecodeerror-in-python-3/
-    # for the error syntax :-)
-    o = b"\x00\x00"
-    docfiles._scan.side_effect = UnicodeDecodeError(
-        "funnycodec", o, 1, 2, "This is just a fake reason!"
-    )
+
+    def mock_scan():
+        # Thanks to
+        # https://gehrcke.de/2015/12/how-to-raise-unicodedecodeerror-in-python-3/
+        # for the error syntax :-)
+        o = b"\x00\x00"
+        if True:
+            raise UnicodeDecodeError(
+                "funnycodec", o, 1, 2, "This is just a fake reason!"
+            )
+        yield "dummy yieldto make it an iterable"
+
+    docfiles._scan = mock_scan
     # The unicode error logs an error but continues otherwise.
     assert list(docfiles.scan()) == []