1 files changed, 71 insertions, 0 deletions
diff --git a/Lib/importlib/test/source/test_reload.py b/Lib/importlib/test/source/test_reload.py
new file mode 100644
index 0000000..e123a28
--- /dev/null
+++ b/Lib/importlib/test/source/test_reload.py
@@ -0,0 +1,71 @@
+"""Test reload support.
+
+Reload support requires two things. One is that if module is loaded that
+already exists in sys.modules then it is reused. And two, if a reload fails the
+pre-existing module is left in a sane state.
+
+"""
+import imp
+import sys
+import types
+import unittest
+import importlib
+from .. import support
+
+
+class ReloadTests(unittest.TestCase):
+
+    name = '_temp'
+
+    def load_module(self, mapping):
+        return importlib._PyFileLoader(self.name, mapping[self.name], False)
+
+    def fake_mtime(self, fxn):
+        """Fake mtime to always be higher than expected."""
+        return lambda name: fxn(name) + 1
+
+    def test_module_reuse(self):
+        with support.create_modules(self.name) as mapping:
+            loader = self.load_module(mapping)
+            module = loader.load_module(self.name)
+            module_id = id(module)
+            module_dict_id = id(module.__dict__)
+            with open(mapping[self.name], 'w') as file:
+                file.write("testing_var = 42\n")
+            # For filesystems where the mtime is only to a second granularity,
+            # everything that has happened above can be too fast;
+            # force an mtime on the source that is guaranteed to be different
+            # than the original mtime.
+            loader.source_mtime = self.fake_mtime(loader.source_mtime)
+            module = loader.load_module(self.name)
+            self.assert_('testing_var' in module.__dict__,
+                         "'testing_var' not in "
+                            "{0}".format(list(module.__dict__.keys())))
+            self.assertEqual(module, sys.modules[self.name])
+            self.assertEqual(id(module), module_id)
+            self.assertEqual(id(module.__dict__), module_dict_id)
+
+    def test_bad_reload(self):
+        # A failed reload should leave the original module intact.
+        attributes = ('__file__', '__path__', '__package__')
+        value = '<test>'
+        with support.create_modules(self.name) as mapping:
+            orig_module = imp.new_module(self.name)
+            for attr in attributes:
+                setattr(orig_module, attr, value)
+            with open(mapping[self.name], 'w') as file:
+                file.write('+++ bad syntax +++')
+            loader = self.load_module(mapping)
+            self.assertRaises(SyntaxError, loader.load_module, self.name)
+            for attr in attributes:
+                self.assertEqual(getattr(orig_module, attr), value)
+
+
+
+def test_main():
+    from test.support import run_unittest
+    run_unittest(ReloadTests)
+
+
+if __name__ == '__main__':
+    test_main()