tests: add testFixNestedExceptTrace

my2to3/tests/__init__.py

+from lib2to3.tests.test_fixers import FixerTestCase as lib2to3FixerTestCase
+
+
+class FixerTestCase(lib2to3FixerTestCase):
+  # Subclass to replace "fixer_pkg"
+  def setUp(self, fix_list=None, fixer_pkg="my2to3", options=None):
+    super(FixerTestCase, self).setUp(fix_list, fixer_pkg, options)
+
+    if self.fixer.endswith('_trace'):
+      fix_name = 'fix_' + self.fixer
+      self.fixer_module = fixer_module = getattr(__import__('my2to3.fixes', fromlist=[fix_name]), fix_name)
+
+      self.traces = []
+      # Wrap fixer_module.trace, to populate self.traces
+      self.old_trace = fixer_module.trace
+      def decorate(func):
+        def call(*args):
+          self.traces.append(args)
+          return func(*args)
+        return call
+      fixer_module.trace = decorate(fixer_module.trace)
+
+  def tearDown(self, *args, **kw):
+    super(FixerTestCase, self).tearDown(*args, **kw)
+
+    if self.fixer.endswith('_trace'):
+      self.fixer_module.trace = self.old_trace

my2to3/tests/testFixDivisionTrace.py

-from lib2to3.tests.test_fixers import FixerTestCase as lib2to3FixerTestCase
 import unittest
 
-
-class FixerTestCase(lib2to3FixerTestCase):
-  # Subclass to replace "fixer_pkg"
-  def setUp(self, fix_list=None, fixer_pkg="my2to3", options=None):
-    super(FixerTestCase, self).setUp(fix_list, fixer_pkg, options)
+from . import FixerTestCase
 
 
 class testFixDivisionTrace(FixerTestCase):

my2to3/tests/testFixNestedExceptTrace.py

+import unittest
+
+from . import FixerTestCase
+
+
+class testFixNestedExceptTrace(FixerTestCase):
+  fixer = "nested_except_trace"
+
+  def test_try(self):
+    a = """
+        try:
+          try:
+            1
+          except Exception as e:
+            2
+        except Exception as e:
+          3
+        """
+    self.assertEqual(self.traces, [])
+    self.unchanged(a)
+    self.assertEqual(self.traces, [])
+
+  def test_except(self):
+    a = """
+        try:
+          1
+        except Exception as e:
+          try:
+            2
+          except Exception as e:
+            3
+        """
+    self.assertEqual(self.traces, [])
+    self.unchanged(a)
+    self.assertEqual(self.traces, [(u'<string>', 4, 7)])
+
+  def test_except_2(self):
+    a = """
+        try:
+          1
+        except Exception as e:
+          try:
+            2
+          except Exception as f:
+            3
+        """
+    self.assertEqual(self.traces, [])
+    self.unchanged(a)
+    self.assertEqual(self.traces, [])
+
+  def test_multiple_except(self):
+    a = """
+        try:
+          1
+        except Exception as e:
+          try:
+            2
+          except Exception as e:
+            try:
+              3
+            except Exception as e:
+              4
+        """
+    self.assertEqual(self.traces, [])
+    self.unchanged(a)
+    self.assertEqual(self.traces, [(u'<string>', 7, 10), (u'<string>', 4, 7), (u'<string>', 4, 10)])
+
+  def test_else(self):
+    a = """
+        try:
+          1
+        except Exception as e:
+          2
+        else:
+          try:
+            3
+          except Exception as e:
+            4
+        """
+    self.assertEqual(self.traces, [])
+    self.unchanged(a)
+    self.assertEqual(self.traces, [])
+
+  def test_finally(self):
+    a = """
+        try:
+          1
+        except Exception as e:
+          2
+        finally:
+          try:
+            3
+          except Exception as e:
+            4
+        """
+    self.assertEqual(self.traces, [])
+    self.unchanged(a)
+    self.assertEqual(self.traces, [])
+
+
+if __name__ == '__main__':
+  unittest.main()