Issue #19591: Use specific asserts in ctype tests.

16 files changed, 84 insertions, 85 deletions

diff --git a/Lib/ctypes/test/test_arrays.py b/Lib/ctypes/test/test_arrays.py
index cfc219e56b..99b97aa7d8 100644
--- a/Lib/ctypes/test/test_arrays.py
+++ b/Lib/ctypes/test/test_arrays.py
@@ -84,8 +84,8 @@ class ArrayTestCase(unittest.TestCase):
         self.assertEqual(values, [1, 2, 3, 4, 5])
 
     def test_classcache(self):
-        self.assertTrue(not ARRAY(c_int, 3) is ARRAY(c_int, 4))
-        self.assertTrue(ARRAY(c_int, 3) is ARRAY(c_int, 3))
+        self.assertIsNot(ARRAY(c_int, 3), ARRAY(c_int, 4))
+        self.assertIs(ARRAY(c_int, 3), ARRAY(c_int, 3))
 
     def test_from_address(self):
         # Failed with 0.9.8, reported by JUrner
@@ -125,7 +125,7 @@ class ArrayTestCase(unittest.TestCase):
         # Create a new array type based on it:
         t1 = my_int * 1
         t2 = my_int * 1
-        self.assertTrue(t1 is t2)
+        self.assertIs(t1, t2)
 
     def test_subclass(self):
         class T(Array):
diff --git a/Lib/ctypes/test/test_as_parameter.py b/Lib/ctypes/test/test_as_parameter.py
index 2657a66d11..43703e3b6e 100644
--- a/Lib/ctypes/test/test_as_parameter.py
+++ b/Lib/ctypes/test/test_as_parameter.py
@@ -134,7 +134,7 @@ class BasicWrapTestCase(unittest.TestCase):
         f.argtypes = [c_longlong, MyCallback]
 
         def callback(value):
-            self.assertTrue(isinstance(value, int))
+            self.assertIsInstance(value, int)
             return value & 0x7FFFFFFF
 
         cb = MyCallback(callback)
diff --git a/Lib/ctypes/test/test_buffers.py b/Lib/ctypes/test/test_buffers.py
index 2dc74841c4..0d12f47afe 100644
--- a/Lib/ctypes/test/test_buffers.py
+++ b/Lib/ctypes/test/test_buffers.py
@@ -7,12 +7,12 @@ class StringBufferTestCase(unittest.TestCase):
         b = create_string_buffer(32)
         self.assertEqual(len(b), 32)
         self.assertEqual(sizeof(b), 32 * sizeof(c_char))
-        self.assertTrue(type(b[0]) is bytes)
+        self.assertIs(type(b[0]), bytes)
 
         b = create_string_buffer(b"abc")
         self.assertEqual(len(b), 4) # trailing nul char
         self.assertEqual(sizeof(b), 4 * sizeof(c_char))
-        self.assertTrue(type(b[0]) is bytes)
+        self.assertIs(type(b[0]), bytes)
         self.assertEqual(b[0], b"a")
         self.assertEqual(b[:], b"abc\0")
         self.assertEqual(b[::], b"abc\0")
@@ -33,12 +33,12 @@ class StringBufferTestCase(unittest.TestCase):
             b = create_unicode_buffer(32)
             self.assertEqual(len(b), 32)
             self.assertEqual(sizeof(b), 32 * sizeof(c_wchar))
-            self.assertTrue(type(b[0]) is str)
+            self.assertIs(type(b[0]), str)
 
             b = create_unicode_buffer("abc")
             self.assertEqual(len(b), 4) # trailing nul char
             self.assertEqual(sizeof(b), 4 * sizeof(c_wchar))
-            self.assertTrue(type(b[0]) is str)
+            self.assertIs(type(b[0]), str)
             self.assertEqual(b[0], "a")
             self.assertEqual(b[:], "abc\0")
             self.assertEqual(b[::], "abc\0")
@@ -50,7 +50,7 @@ class StringBufferTestCase(unittest.TestCase):
             b = create_unicode_buffer("abc")
             self.assertEqual(len(b), 4) # trailing nul char
             self.assertEqual(sizeof(b), 4 * sizeof(c_wchar))
-            self.assertTrue(type(b[0]) is str)
+            self.assertIs(type(b[0]), str)
             self.assertEqual(b[0], "a")
             self.assertEqual(b[:], "abc\0")
             self.assertEqual(b[::], "abc\0")
diff --git a/Lib/ctypes/test/test_byteswap.py b/Lib/ctypes/test/test_byteswap.py
index 0d2974fdd9..63dde13519 100644
--- a/Lib/ctypes/test/test_byteswap.py
+++ b/Lib/ctypes/test/test_byteswap.py
@@ -23,11 +23,11 @@ class Test(unittest.TestCase):
 
     def test_endian_short(self):
         if sys.byteorder == "little":
-            self.assertTrue(c_short.__ctype_le__ is c_short)
-            self.assertTrue(c_short.__ctype_be__.__ctype_le__ is c_short)
+            self.assertIs(c_short.__ctype_le__, c_short)
+            self.assertIs(c_short.__ctype_be__.__ctype_le__, c_short)
         else:
-            self.assertTrue(c_short.__ctype_be__ is c_short)
-            self.assertTrue(c_short.__ctype_le__.__ctype_be__ is c_short)
+            self.assertIs(c_short.__ctype_be__, c_short)
+            self.assertIs(c_short.__ctype_le__.__ctype_be__, c_short)
         s = c_short.__ctype_be__(0x1234)
         self.assertEqual(bin(struct.pack(">h", 0x1234)), "1234")
         self.assertEqual(bin(s), "1234")
@@ -50,11 +50,11 @@ class Test(unittest.TestCase):
 
     def test_endian_int(self):
         if sys.byteorder == "little":
-            self.assertTrue(c_int.__ctype_le__ is c_int)
-            self.assertTrue(c_int.__ctype_be__.__ctype_le__ is c_int)
+            self.assertIs(c_int.__ctype_le__, c_int)
+            self.assertIs(c_int.__ctype_be__.__ctype_le__, c_int)
         else:
-            self.assertTrue(c_int.__ctype_be__ is c_int)
-            self.assertTrue(c_int.__ctype_le__.__ctype_be__ is c_int)
+            self.assertIs(c_int.__ctype_be__, c_int)
+            self.assertIs(c_int.__ctype_le__.__ctype_be__, c_int)
 
         s = c_int.__ctype_be__(0x12345678)
         self.assertEqual(bin(struct.pack(">i", 0x12345678)), "12345678")
@@ -78,11 +78,11 @@ class Test(unittest.TestCase):
 
     def test_endian_longlong(self):
         if sys.byteorder == "little":
-            self.assertTrue(c_longlong.__ctype_le__ is c_longlong)
-            self.assertTrue(c_longlong.__ctype_be__.__ctype_le__ is c_longlong)
+            self.assertIs(c_longlong.__ctype_le__, c_longlong)
+            self.assertIs(c_longlong.__ctype_be__.__ctype_le__, c_longlong)
         else:
-            self.assertTrue(c_longlong.__ctype_be__ is c_longlong)
-            self.assertTrue(c_longlong.__ctype_le__.__ctype_be__ is c_longlong)
+            self.assertIs(c_longlong.__ctype_be__, c_longlong)
+            self.assertIs(c_longlong.__ctype_le__.__ctype_be__, c_longlong)
 
         s = c_longlong.__ctype_be__(0x1234567890ABCDEF)
         self.assertEqual(bin(struct.pack(">q", 0x1234567890ABCDEF)), "1234567890ABCDEF")
@@ -106,11 +106,11 @@ class Test(unittest.TestCase):
 
     def test_endian_float(self):
         if sys.byteorder == "little":
-            self.assertTrue(c_float.__ctype_le__ is c_float)
-            self.assertTrue(c_float.__ctype_be__.__ctype_le__ is c_float)
+            self.assertIs(c_float.__ctype_le__, c_float)
+            self.assertIs(c_float.__ctype_be__.__ctype_le__, c_float)
         else:
-            self.assertTrue(c_float.__ctype_be__ is c_float)
-            self.assertTrue(c_float.__ctype_le__.__ctype_be__ is c_float)
+            self.assertIs(c_float.__ctype_be__, c_float)
+            self.assertIs(c_float.__ctype_le__.__ctype_be__, c_float)
         s = c_float(math.pi)
         self.assertEqual(bin(struct.pack("f", math.pi)), bin(s))
         # Hm, what's the precision of a float compared to a double?
@@ -124,11 +124,11 @@ class Test(unittest.TestCase):
 
     def test_endian_double(self):
         if sys.byteorder == "little":
-            self.assertTrue(c_double.__ctype_le__ is c_double)
-            self.assertTrue(c_double.__ctype_be__.__ctype_le__ is c_double)
+            self.assertIs(c_double.__ctype_le__, c_double)
+            self.assertIs(c_double.__ctype_be__.__ctype_le__, c_double)
         else:
-            self.assertTrue(c_double.__ctype_be__ is c_double)
-            self.assertTrue(c_double.__ctype_le__.__ctype_be__ is c_double)
+            self.assertIs(c_double.__ctype_be__, c_double)
+            self.assertIs(c_double.__ctype_le__.__ctype_be__, c_double)
         s = c_double(math.pi)
         self.assertEqual(s.value, math.pi)
         self.assertEqual(bin(struct.pack("d", math.pi)), bin(s))
@@ -140,14 +140,14 @@ class Test(unittest.TestCase):
         self.assertEqual(bin(struct.pack(">d", math.pi)), bin(s))
 
     def test_endian_other(self):
-        self.assertTrue(c_byte.__ctype_le__ is c_byte)
-        self.assertTrue(c_byte.__ctype_be__ is c_byte)
+        self.assertIs(c_byte.__ctype_le__, c_byte)
+        self.assertIs(c_byte.__ctype_be__, c_byte)
 
-        self.assertTrue(c_ubyte.__ctype_le__ is c_ubyte)
-        self.assertTrue(c_ubyte.__ctype_be__ is c_ubyte)
+        self.assertIs(c_ubyte.__ctype_le__, c_ubyte)
+        self.assertIs(c_ubyte.__ctype_be__, c_ubyte)
 
-        self.assertTrue(c_char.__ctype_le__ is c_char)
-        self.assertTrue(c_char.__ctype_be__ is c_char)
+        self.assertIs(c_char.__ctype_le__, c_char)
+        self.assertIs(c_char.__ctype_be__, c_char)
 
     def test_struct_fields_1(self):
         if sys.byteorder == "little":
diff --git a/Lib/ctypes/test/test_cast.py b/Lib/ctypes/test/test_cast.py
index 702de3cffa..32496f6863 100644
--- a/Lib/ctypes/test/test_cast.py
+++ b/Lib/ctypes/test/test_cast.py
@@ -38,14 +38,14 @@ class Test(unittest.TestCase):
 
         p = cast(array, POINTER(c_char_p))
         # array and p share a common _objects attribute
-        self.assertTrue(p._objects is array._objects)
+        self.assertIs(p._objects, array._objects)
         self.assertEqual(array._objects, {'0': b"foo bar", id(array): array})
         p[0] = b"spam spam"
         self.assertEqual(p._objects, {'0': b"spam spam", id(array): array})
-        self.assertTrue(array._objects is p._objects)
+        self.assertIs(array._objects, p._objects)
         p[1] = b"foo bar"
         self.assertEqual(p._objects, {'1': b'foo bar', '0': b"spam spam", id(array): array})
-        self.assertTrue(array._objects is p._objects)
+        self.assertIs(array._objects, p._objects)
 
     def test_other(self):
         p = cast((c_int * 4)(1, 2, 3, 4), POINTER(c_int))
diff --git a/Lib/ctypes/test/test_frombuffer.py b/Lib/ctypes/test/test_frombuffer.py
index 92d61580dd..ffb27a6ea3 100644
--- a/Lib/ctypes/test/test_frombuffer.py
+++ b/Lib/ctypes/test/test_frombuffer.py
@@ -23,7 +23,7 @@ class Test(unittest.TestCase):
         a[0], a[-1] = 200, -200
         self.assertEqual(x[:], a.tolist())
 
-        self.assertTrue(a in x._objects.values())
+        self.assertIn(a, x._objects.values())
 
         self.assertRaises(ValueError,
                           c_int.from_buffer, a, -1)
diff --git a/Lib/ctypes/test/test_funcptr.py b/Lib/ctypes/test/test_funcptr.py
index 13bf4088bf..ff25c8febd 100644
--- a/Lib/ctypes/test/test_funcptr.py
+++ b/Lib/ctypes/test/test_funcptr.py
@@ -75,7 +75,7 @@ class CFuncPtrTestCase(unittest.TestCase):
         ##                  "lpfnWndProc", WNDPROC_2(wndproc))
         # instead:
 
-        self.assertTrue(WNDPROC is WNDPROC_2)
+        self.assertIs(WNDPROC, WNDPROC_2)
         # 'wndclass.lpfnWndProc' leaks 94 references.  Why?
         self.assertEqual(wndclass.lpfnWndProc(1, 2, 3, 4), 10)
 
diff --git a/Lib/ctypes/test/test_functions.py b/Lib/ctypes/test/test_functions.py
index 45d74ec9e8..07eeb68924 100644
--- a/Lib/ctypes/test/test_functions.py
+++ b/Lib/ctypes/test/test_functions.py
@@ -306,7 +306,7 @@ class FunctionTestCase(unittest.TestCase):
         f.argtypes = [c_longlong, MyCallback]
 
         def callback(value):
-            self.assertTrue(isinstance(value, int))
+            self.assertIsInstance(value, int)
             return value & 0x7FFFFFFF
 
         cb = MyCallback(callback)
diff --git a/Lib/ctypes/test/test_loading.py b/Lib/ctypes/test/test_loading.py
index 4029b463bc..414363d8c8 100644
--- a/Lib/ctypes/test/test_loading.py
+++ b/Lib/ctypes/test/test_loading.py
@@ -43,7 +43,7 @@ class LoaderTest(unittest.TestCase):
 
     if os.name in ("nt", "ce"):
         def test_load_library(self):
-            self.assertFalse(libc_name is None)
+            self.assertIsNotNone(libc_name)
             if is_resource_enabled("printing"):
                 print(find_library("kernel32"))
                 print(find_library("user32"))
diff --git a/Lib/ctypes/test/test_numbers.py b/Lib/ctypes/test/test_numbers.py
index c02abf9c32..3b7194f31c 100644
--- a/Lib/ctypes/test/test_numbers.py
+++ b/Lib/ctypes/test/test_numbers.py
@@ -181,10 +181,10 @@ class NumberTestCase(unittest.TestCase):
             a = array(t._type_, [3.14])
             v = t.from_address(a.buffer_info()[0])
             self.assertEqual(v.value, a[0])
-            self.assertTrue(type(v) is t)
+            self.assertIs(type(v), t)
             a[0] = 2.3456e17
             self.assertEqual(v.value, a[0])
-            self.assertTrue(type(v) is t)
+            self.assertIs(type(v), t)
 
     def test_char_from_address(self):
         from ctypes import c_char
@@ -194,7 +194,7 @@ class NumberTestCase(unittest.TestCase):
         a[0] = ord('x')
         v = c_char.from_address(a.buffer_info()[0])
         self.assertEqual(v.value, b'x')
-        self.assertTrue(type(v) is c_char)
+        self.assertIs(type(v), c_char)
 
         a[0] = ord('?')
         self.assertEqual(v.value, b'?')
diff --git a/Lib/ctypes/test/test_parameters.py b/Lib/ctypes/test/test_parameters.py
index 9762fb915d..12b5bd5fba 100644
--- a/Lib/ctypes/test/test_parameters.py
+++ b/Lib/ctypes/test/test_parameters.py
@@ -54,7 +54,7 @@ class SimpleTypesTestCase(unittest.TestCase):
         # c_char_p.from_param on a Python String packs the string
         # into a cparam object
         s = b"123"
-        self.assertTrue(c_char_p.from_param(s)._obj is s)
+        self.assertIs(c_char_p.from_param(s)._obj, s)
 
         # new in 0.9.1: convert (encode) unicode to ascii
         self.assertEqual(c_char_p.from_param(b"123")._obj, b"123")
@@ -64,7 +64,7 @@ class SimpleTypesTestCase(unittest.TestCase):
         # calling c_char_p.from_param with a c_char_p instance
         # returns the argument itself:
         a = c_char_p(b"123")
-        self.assertTrue(c_char_p.from_param(a) is a)
+        self.assertIs(c_char_p.from_param(a), a)
 
     def test_cw_strings(self):
         from ctypes import byref
diff --git a/Lib/ctypes/test/test_pointers.py b/Lib/ctypes/test/test_pointers.py
index d29317a3e4..f8ef0ab830 100644
--- a/Lib/ctypes/test/test_pointers.py
+++ b/Lib/ctypes/test/test_pointers.py
@@ -78,7 +78,7 @@ class PointersTestCase(unittest.TestCase):
 
 ##        i = c_int(42)
 ##        callback(byref(i))
-##        self.assertTrue(i.value == 84)
+##        self.assertEqual(i.value, 84)
 
         doit(callback)
 ##        print self.result
@@ -91,11 +91,11 @@ class PointersTestCase(unittest.TestCase):
             i = ct(42)
             p = pointer(i)
 ##            print type(p.contents), ct
-            self.assertTrue(type(p.contents) is ct)
+            self.assertIs(type(p.contents), ct)
             # p.contents is the same as p[0]
 ##            print p.contents
-##            self.assertTrue(p.contents == 42)
-##            self.assertTrue(p[0] == 42)
+##            self.assertEqual(p.contents, 42)
+##            self.assertEqual(p[0], 42)
 
             self.assertRaises(TypeError, delitem, p, 0)
 
diff --git a/Lib/ctypes/test/test_python_api.py b/Lib/ctypes/test/test_python_api.py
index 9de3980ed4..5eb882af5e 100644
--- a/Lib/ctypes/test/test_python_api.py
+++ b/Lib/ctypes/test/test_python_api.py
@@ -64,7 +64,7 @@ class PythonAPITestCase(unittest.TestCase):
         ref = grc(s)
         # id(python-object) is the address
         pyobj = PyObj_FromPtr(id(s))
-        self.assertTrue(s is pyobj)
+        self.assertIs(s, pyobj)
 
         self.assertEqual(grc(s), ref + 1)
         del pyobj
diff --git a/Lib/ctypes/test/test_refcounts.py b/Lib/ctypes/test/test_refcounts.py
index a483bb0bbc..f2edfa6400 100644
--- a/Lib/ctypes/test/test_refcounts.py
+++ b/Lib/ctypes/test/test_refcounts.py
@@ -26,7 +26,7 @@ class RefcountTestCase(unittest.TestCase):
         self.assertEqual(grc(callback), 2)
         cb = MyCallback(callback)
 
-        self.assertTrue(grc(callback) > 2)
+        self.assertGreater(grc(callback), 2)
         result = f(-10, cb)
         self.assertEqual(result, -18)
         cb = None
@@ -46,15 +46,15 @@ class RefcountTestCase(unittest.TestCase):
 
         # the CFuncPtr instance holds at least one refcount on func:
         f = OtherCallback(func)
-        self.assertTrue(grc(func) > 2)
+        self.assertGreater(grc(func), 2)
 
         # and may release it again
         del f
-        self.assertTrue(grc(func) >= 2)
+        self.assertGreaterEqual(grc(func), 2)
 
         # but now it must be gone
         gc.collect()
-        self.assertTrue(grc(func) == 2)
+        self.assertEqual(grc(func), 2)
 
         class X(ctypes.Structure):
             _fields_ = [("a", OtherCallback)]
@@ -62,11 +62,11 @@ class RefcountTestCase(unittest.TestCase):
         x.a = OtherCallback(func)
 
         # the CFuncPtr instance holds at least one refcount on func:
-        self.assertTrue(grc(func) > 2)
+        self.assertGreater(grc(func), 2)
 
         # and may release it again
         del x
-        self.assertTrue(grc(func) >= 2)
+        self.assertGreaterEqual(grc(func), 2)
 
         # and now it must be gone again
         gc.collect()
@@ -75,7 +75,7 @@ class RefcountTestCase(unittest.TestCase):
         f = OtherCallback(func)
 
         # the CFuncPtr instance holds at least one refcount on func:
-        self.assertTrue(grc(func) > 2)
+        self.assertGreater(grc(func), 2)
 
         # create a cycle
         f.cycle = f
diff --git a/Lib/ctypes/test/test_strings.py b/Lib/ctypes/test/test_strings.py
index 1a9bdbc5c0..9dc2a291a7 100644
--- a/Lib/ctypes/test/test_strings.py
+++ b/Lib/ctypes/test/test_strings.py
@@ -115,24 +115,24 @@ class StringTestCase(unittest.TestCase):
 
         # New in releases later than 0.4.0:
         # c_string(number) returns an empty string of size number
-        self.assertTrue(len(c_string(32).raw) == 32)
+        self.assertEqual(len(c_string(32).raw), 32)
         self.assertRaises(ValueError, c_string, -1)
         self.assertRaises(ValueError, c_string, 0)
 
         # These tests fail, because it is no longer initialized
-##        self.assertTrue(c_string(2).value == "")
-##        self.assertTrue(c_string(2).raw == "\000\000")
-        self.assertTrue(c_string(2).raw[-1] == "\000")
-        self.assertTrue(len(c_string(2).raw) == 2)
+##        self.assertEqual(c_string(2).value, "")
+##        self.assertEqual(c_string(2).raw, "\000\000")
+        self.assertEqual(c_string(2).raw[-1], "\000")
+        self.assertEqual(len(c_string(2).raw), 2)
 
     def XX_test_initialized_strings(self):
 
-        self.assertTrue(c_string("ab", 4).raw[:2] == "ab")
-        self.assertTrue(c_string("ab", 4).raw[:2:] == "ab")
-        self.assertTrue(c_string("ab", 4).raw[:2:-1] == "ba")
-        self.assertTrue(c_string("ab", 4).raw[:2:2] == "a")
-        self.assertTrue(c_string("ab", 4).raw[-1] == "\000")
-        self.assertTrue(c_string("ab", 2).raw == "a\000")
+        self.assertEqual(c_string("ab", 4).raw[:2], "ab")
+        self.assertEqual(c_string("ab", 4).raw[:2:], "ab")
+        self.assertEqual(c_string("ab", 4).raw[:2:-1], "ba")
+        self.assertEqual(c_string("ab", 4).raw[:2:2], "a")
+        self.assertEqual(c_string("ab", 4).raw[-1], "\000")
+        self.assertEqual(c_string("ab", 2).raw, "a\000")
 
     def XX_test_toolong(self):
         cs = c_string("abcdef")
@@ -163,22 +163,22 @@ else:
             # XXX This behaviour is about to change:
             # len returns the size of the internal buffer in bytes.
             # This includes the terminating NUL character.
-            self.assertTrue(sizeof(cs) == 14)
+            self.assertEqual(sizeof(cs), 14)
 
             # The value property is the string up to the first terminating NUL.
-            self.assertTrue(cs.value == "abcdef")
-            self.assertTrue(c_wstring("abc\000def").value == "abc")
+            self.assertEqual(cs.value, "abcdef")
+            self.assertEqual(c_wstring("abc\000def").value, "abc")
 
-            self.assertTrue(c_wstring("abc\000def").value == "abc")
+            self.assertEqual(c_wstring("abc\000def").value, "abc")
 
             # The raw property is the total buffer contents:
-            self.assertTrue(cs.raw == "abcdef\000")
-            self.assertTrue(c_wstring("abc\000def").raw == "abc\000def\000")
+            self.assertEqual(cs.raw, "abcdef\000")
+            self.assertEqual(c_wstring("abc\000def").raw, "abc\000def\000")
 
             # We can change the value:
             cs.value = "ab"
-            self.assertTrue(cs.value == "ab")
-            self.assertTrue(cs.raw == "ab\000\000\000\000\000")
+            self.assertEqual(cs.value, "ab")
+            self.assertEqual(cs.raw, "ab\000\000\000\000\000")
 
             self.assertRaises(TypeError, c_wstring, "123")
             self.assertRaises(ValueError, c_wstring, 0)
diff --git a/Lib/ctypes/test/test_structures.py b/Lib/ctypes/test/test_structures.py
index 9d5b99e2f8..61b9fe7c18 100644
--- a/Lib/ctypes/test/test_structures.py
+++ b/Lib/ctypes/test/test_structures.py
@@ -374,9 +374,9 @@ class StructureTestCase(unittest.TestCase):
 ##        class X(Structure):
 ##            _fields_ = []
 
-        self.assertTrue("in_dll" in dir(type(Structure)))
-        self.assertTrue("from_address" in dir(type(Structure)))
-        self.assertTrue("in_dll" in dir(type(Structure)))
+        self.assertIn("in_dll", dir(type(Structure)))
+        self.assertIn("from_address", dir(type(Structure)))
+        self.assertIn("in_dll", dir(type(Structure)))
 
     def test_positional_args(self):
         # see also http://bugs.python.org/issue5042
@@ -446,8 +446,8 @@ class TestRecursiveStructure(unittest.TestCase):
         try:
             Recursive._fields_ = [("next", Recursive)]
         except AttributeError as details:
-            self.assertTrue("Structure or union cannot contain itself" in
-                            str(details))
+            self.assertIn("Structure or union cannot contain itself",
+                          str(details))
         else:
             self.fail("Structure or union cannot contain itself")
 
@@ -463,8 +463,7 @@ class TestRecursiveStructure(unittest.TestCase):
         try:
             Second._fields_ = [("first", First)]
         except AttributeError as details:
-            self.assertTrue("_fields_ is final" in
-                            str(details))
+            self.assertIn("_fields_ is final", str(details))
         else:
             self.fail("AttributeError not raised")