Fix test runs without lingua or babel

Defer test imports to fall within exclusion decorators
Support for identifying new 3.11-style error message

Closes: #357
Pull-request: https://github.com/sqlalchemy/mako/pull/357
Pull-request-sha: 44f788b4f3a3c3e1f8328670a2334555163b90e2
Change-Id: I39d59383d92e041e10adc967f51d74839105a1eb

4 files changed, 33 insertions, 12 deletions

diff --git a/mako/testing/fixtures.py b/mako/testing/fixtures.py
index c9379c0..01e9961 100644
--- a/mako/testing/fixtures.py
+++ b/mako/testing/fixtures.py
@@ -80,6 +80,16 @@ class TemplateTest:
             output = filters(output)
         eq_(output, expected)
 
+    def indicates_unbound_local_error(self, rendered_output, unbound_var):
+        var = f"'{unbound_var}'"
+        error_msgs = (
+            # < 3.11
+            f"local variable {var} referenced before assignment",
+            # >= 3.11
+            f"cannot access local variable {var} where it is not associated",
+        )
+        return any((msg in rendered_output) for msg in error_msgs)
+
 
 class PlainCacheImpl(CacheImpl):
     """Simple memory cache impl so that tests which
diff --git a/test/ext/test_babelplugin.py b/test/ext/test_babelplugin.py
index de3e461..cfe79b6 100644
--- a/test/ext/test_babelplugin.py
+++ b/test/ext/test_babelplugin.py
@@ -1,26 +1,35 @@
 import io
 import os
 
-from mako.ext.babelplugin import extract
+import pytest
+
 from mako.testing.assertions import eq_
 from mako.testing.config import config
 from mako.testing.exclusions import requires_babel
 from mako.testing.fixtures import TemplateTest
 
 
+class UsesExtract:
+    @pytest.fixture(scope="class")
+    def extract(self):
+        from mako.ext.babelplugin import extract
+
+        return extract
+
+
 @requires_babel
-class PluginExtractTest:
-    def test_parse_python_expression(self):
+class PluginExtractTest(UsesExtract):
+    def test_parse_python_expression(self, extract):
         input_ = io.BytesIO(b'<p>${_("Message")}</p>')
         messages = list(extract(input_, ["_"], [], {}))
         eq_(messages, [(1, "_", ("Message"), [])])
 
-    def test_python_gettext_call(self):
+    def test_python_gettext_call(self, extract):
         input_ = io.BytesIO(b'<p>${_("Message")}</p>')
         messages = list(extract(input_, ["_"], [], {}))
         eq_(messages, [(1, "_", ("Message"), [])])
 
-    def test_translator_comment(self):
+    def test_translator_comment(self, extract):
         input_ = io.BytesIO(
             b"""
         <p>
@@ -43,8 +52,8 @@ class PluginExtractTest:
 
 
 @requires_babel
-class MakoExtractTest(TemplateTest):
-    def test_extract(self):
+class MakoExtractTest(UsesExtract, TemplateTest):
+    def test_extract(self, extract):
         with open(
             os.path.join(config.template_base, "gettext.mako")
         ) as mako_tmpl:
@@ -83,7 +92,7 @@ class MakoExtractTest(TemplateTest):
             ]
         eq_(expected, messages)
 
-    def test_extract_utf8(self):
+    def test_extract_utf8(self, extract):
         with open(
             os.path.join(config.template_base, "gettext_utf8.mako"), "rb"
         ) as mako_tmpl:
@@ -92,7 +101,7 @@ class MakoExtractTest(TemplateTest):
             )
             assert message == (1, "_", "K\xf6ln", [])
 
-    def test_extract_cp1251(self):
+    def test_extract_cp1251(self, extract):
         with open(
             os.path.join(config.template_base, "gettext_cp1251.mako"), "rb"
         ) as mako_tmpl:
diff --git a/test/ext/test_linguaplugin.py b/test/ext/test_linguaplugin.py
index ae24f67..6e2faa8 100644
--- a/test/ext/test_linguaplugin.py
+++ b/test/ext/test_linguaplugin.py
@@ -2,7 +2,6 @@ import os
 
 import pytest
 
-from mako.ext.linguaplugin import LinguaMakoExtractor
 from mako.testing.assertions import eq_
 from mako.testing.config import config
 from mako.testing.exclusions import requires_lingua
@@ -24,6 +23,8 @@ class MakoExtractTest(TemplateTest):
         register_extractors()
 
     def test_extract(self):
+        from mako.ext.linguaplugin import LinguaMakoExtractor
+
         plugin = LinguaMakoExtractor({"comment-tags": "TRANSLATOR"})
         messages = list(
             plugin(
diff --git a/test/test_exceptions.py b/test/test_exceptions.py
index 4a90b90..be573e6 100644
--- a/test/test_exceptions.py
+++ b/test/test_exceptions.py
@@ -274,7 +274,8 @@ ${foobar}
         html_error = exceptions.html_error_template().render_unicode(
             error=v, traceback=None
         )
-        assert "local variable &#39;y&#39;" in html_error
+
+        assert self.indicates_unbound_local_error(html_error, "y")
 
     def test_tback_trace_from_py_file(self):
         t = self._file_template("runtimeerr.html")
@@ -284,7 +285,7 @@ ${foobar}
         except:
             html_error = exceptions.html_error_template().render_unicode()
 
-        assert "local variable &#39;y&#39;" in html_error
+        assert self.indicates_unbound_local_error(html_error, "y")
 
     def test_code_block_line_number(self):
         l = TemplateLookup()