1 files changed, 70 insertions, 0 deletions
diff --git a/Lib/test/test_importlib/source/test_case_sensitivity.py b/Lib/test/test_importlib/source/test_case_sensitivity.py
new file mode 100644
index 0000000000..241173fb44
--- /dev/null
+++ b/Lib/test/test_importlib/source/test_case_sensitivity.py
@@ -0,0 +1,70 @@
+"""Test case-sensitivity (PEP 235)."""
+from importlib import _bootstrap
+from importlib import machinery
+from .. import util
+from . import util as source_util
+import imp
+import os
+import sys
+from test import support as test_support
+import unittest
+
+
+@util.case_insensitive_tests
+class CaseSensitivityTest(unittest.TestCase):
+
+    """PEP 235 dictates that on case-preserving, case-insensitive file systems
+    that imports are case-sensitive unless the PYTHONCASEOK environment
+    variable is set."""
+
+    name = 'MoDuLe'
+    assert name != name.lower()
+
+    def find(self, path):
+        finder = machinery.FileFinder(path,
+                                      (machinery.SourceFileLoader,
+                                            machinery.SOURCE_SUFFIXES),
+                                        (machinery.SourcelessFileLoader,
+                                            machinery.BYTECODE_SUFFIXES))
+        return finder.find_module(self.name)
+
+    def sensitivity_test(self):
+        """Look for a module with matching and non-matching sensitivity."""
+        sensitive_pkg = 'sensitive.{0}'.format(self.name)
+        insensitive_pkg = 'insensitive.{0}'.format(self.name.lower())
+        context = source_util.create_modules(insensitive_pkg, sensitive_pkg)
+        with context as mapping:
+            sensitive_path = os.path.join(mapping['.root'], 'sensitive')
+            insensitive_path = os.path.join(mapping['.root'], 'insensitive')
+            return self.find(sensitive_path), self.find(insensitive_path)
+
+    def test_sensitive(self):
+        with test_support.EnvironmentVarGuard() as env:
+            env.unset('PYTHONCASEOK')
+            if b'PYTHONCASEOK' in _bootstrap._os.environ:
+                self.skipTest('os.environ changes not reflected in '
+                              '_os.environ')
+            sensitive, insensitive = self.sensitivity_test()
+            self.assertTrue(hasattr(sensitive, 'load_module'))
+            self.assertIn(self.name, sensitive.get_filename(self.name))
+            self.assertIsNone(insensitive)
+
+    def test_insensitive(self):
+        with test_support.EnvironmentVarGuard() as env:
+            env.set('PYTHONCASEOK', '1')
+            if b'PYTHONCASEOK' not in _bootstrap._os.environ:
+                self.skipTest('os.environ changes not reflected in '
+                              '_os.environ')
+            sensitive, insensitive = self.sensitivity_test()
+            self.assertTrue(hasattr(sensitive, 'load_module'))
+            self.assertIn(self.name, sensitive.get_filename(self.name))
+            self.assertTrue(hasattr(insensitive, 'load_module'))
+            self.assertIn(self.name, insensitive.get_filename(self.name))
+
+
+def test_main():
+    test_support.run_unittest(CaseSensitivityTest)
+
+
+if __name__ == '__main__':
+    test_main()