Issue #19592: Use specific asserts in lib2to3 tests.

Lib/lib2to3/tests/test_fixers.py

@@ -41,7 +41,7 @@ class FixerTestCase(support.TestCase):
 
     def warns(self, before, after, message, unchanged=False):
         tree = self._check(before, after)
-        self.assertTrue(message in "".join(self.fixer_log))
+        self.assertIn(message, "".join(self.fixer_log))
         if not unchanged:
             self.assertTrue(tree.was_changed)
 

Lib/lib2to3/tests/test_main.py

@@ -49,9 +49,9 @@ class TestMain(unittest.TestCase):
         ret = self.run_2to3_capture(["-"], input_stream, out_enc, err)
         self.assertEqual(ret, 0)
         output = out.getvalue().decode("ascii")
-        self.assertTrue("-print 'nothing'" in output)
-        self.assertTrue("WARNING: couldn't encode <stdin>'s diff for "
-                        "your terminal" in err.getvalue())
+        self.assertIn("-print 'nothing'", output)
+        self.assertIn("WARNING: couldn't encode <stdin>'s diff for "
+                      "your terminal", err.getvalue())
 
     def setup_test_source_trees(self):
         """Setup a test source tree and output destination tree."""

Lib/lib2to3/tests/test_parser.py

@@ -168,8 +168,8 @@ class TestParserIdempotency(support.TestCase):
         for filepath in support.all_project_files():
             with open(filepath, "rb") as fp:
                 encoding = tokenize.detect_encoding(fp.readline)[0]
-            self.assertTrue(encoding is not None,
-                            "can't detect encoding for %s" % filepath)
+            self.assertIsNotNone(encoding,
+                                 "can't detect encoding for %s" % filepath)
             with open(filepath, "r", encoding=encoding) as fp:
                 source = fp.read()
             try:

Lib/lib2to3/tests/test_pytree.py

@@ -143,12 +143,12 @@ class TestNodes(support.TestCase):
         l3 = pytree.Leaf(100, "bar")
         n1 = pytree.Node(1000, [l1, l2, l3])
         self.assertEqual(n1.children, [l1, l2, l3])
-        self.assertTrue(isinstance(n1.children, list))
+        self.assertIsInstance(n1.children, list)
         self.assertFalse(n1.was_changed)
         l2new = pytree.Leaf(100, "-")
         l2.replace(l2new)
         self.assertEqual(n1.children, [l1, l2new, l3])
-        self.assertTrue(isinstance(n1.children, list))
+        self.assertIsInstance(n1.children, list)
         self.assertTrue(n1.was_changed)
 
     def test_replace_with_list(self):
@@ -159,7 +159,7 @@ class TestNodes(support.TestCase):
 
         l2.replace([pytree.Leaf(100, "*"), pytree.Leaf(100, "*")])
         self.assertEqual(str(n1), "foo**bar")
-        self.assertTrue(isinstance(n1.children, list))
+        self.assertIsInstance(n1.children, list)
 
     def test_leaves(self):
         l1 = pytree.Leaf(100, "foo")
@@ -330,7 +330,7 @@ class TestNodes(support.TestCase):
         n2 = pytree.Node(1000, [])
         p1 = pytree.Node(1000, [n1, n2])
 
-        self.assertTrue(n1.next_sibling is n2)
+        self.assertIs(n1.next_sibling, n2)
         self.assertEqual(n2.next_sibling, None)
         self.assertEqual(p1.next_sibling, None)
 
@@ -339,7 +339,7 @@ class TestNodes(support.TestCase):
         l2 = pytree.Leaf(100, "b")
         p1 = pytree.Node(1000, [l1, l2])
 
-        self.assertTrue(l1.next_sibling is l2)
+        self.assertIs(l1.next_sibling, l2)
         self.assertEqual(l2.next_sibling, None)
         self.assertEqual(p1.next_sibling, None)
 
@@ -348,7 +348,7 @@ class TestNodes(support.TestCase):
         n2 = pytree.Node(1000, [])
         p1 = pytree.Node(1000, [n1, n2])
 
-        self.assertTrue(n2.prev_sibling is n1)
+        self.assertIs(n2.prev_sibling, n1)
         self.assertEqual(n1.prev_sibling, None)
         self.assertEqual(p1.prev_sibling, None)
 
@@ -357,7 +357,7 @@ class TestNodes(support.TestCase):
         l2 = pytree.Leaf(100, "b")
         p1 = pytree.Node(1000, [l1, l2])
 
-        self.assertTrue(l2.prev_sibling is l1)
+        self.assertIs(l2.prev_sibling, l1)
         self.assertEqual(l1.prev_sibling, None)
         self.assertEqual(p1.prev_sibling, None)
 
@@ -430,7 +430,7 @@ class TestPatterns(support.TestCase):
         r = {}
         self.assertTrue(pw.match_seq([l1, l3], r))
         self.assertEqual(r, {"pl": l3, "pw": [l1, l3]})
-        self.assertTrue(r["pl"] is l3)
+        self.assertIs(r["pl"], l3)
         r = {}
 
     def test_generate_matches(self):

Lib/lib2to3/tests/test_refactor.py

@@ -49,9 +49,9 @@ class TestRefactoringTool(unittest.TestCase):
 
     def test_print_function_option(self):
         rt = self.rt({"print_function" : True})
-        self.assertTrue(rt.grammar is pygram.python_grammar_no_print_statement)
-        self.assertTrue(rt.driver.grammar is
-                        pygram.python_grammar_no_print_statement)
+        self.assertIs(rt.grammar, pygram.python_grammar_no_print_statement)
+        self.assertIs(rt.driver.grammar,
+                      pygram.python_grammar_no_print_statement)
 
     def test_write_unchanged_files_option(self):
         rt = self.rt()