def test_commit(self):
         self.run_commit_test(mid_img, backing_img)
-        self.assertEqual(-1, qemu_io('-f', 'raw', '-c', 'read -P 0xab 0 524288', backing_img).find("verification failed"))
-        self.assertEqual(-1, qemu_io('-f', 'raw', '-c', 'read -P 0xef 524288 524288', backing_img).find("verification failed"))
+        qemu_io('-f', 'raw', '-c', 'read -P 0xab 0 524288', backing_img)
+        qemu_io('-f', 'raw', '-c', 'read -P 0xef 524288 524288', backing_img)
 
     def test_commit_node(self):
         self.run_commit_test("mid", "base", node_names=True)
-        self.assertEqual(-1, qemu_io('-f', 'raw', '-c', 'read -P 0xab 0 524288', backing_img).find("verification failed"))
-        self.assertEqual(-1, qemu_io('-f', 'raw', '-c', 'read -P 0xef 524288 524288', backing_img).find("verification failed"))
+        qemu_io('-f', 'raw', '-c', 'read -P 0xab 0 524288', backing_img)
+        qemu_io('-f', 'raw', '-c', 'read -P 0xef 524288 524288', backing_img)
 
     @iotests.skip_if_unsupported(['throttle'])
     def test_commit_with_filter_and_quit(self):
 
     def test_top_is_active(self):
         self.run_commit_test(test_img, backing_img, need_ready=True)
-        self.assertEqual(-1, qemu_io('-f', 'raw', '-c', 'read -P 0xab 0 524288', backing_img).find("verification failed"))
-        self.assertEqual(-1, qemu_io('-f', 'raw', '-c', 'read -P 0xef 524288 524288', backing_img).find("verification failed"))
+        qemu_io('-f', 'raw', '-c', 'read -P 0xab 0 524288', backing_img)
+        qemu_io('-f', 'raw', '-c', 'read -P 0xef 524288 524288', backing_img)
 
     def test_top_is_default_active(self):
         self.run_default_commit_test()
-        self.assertEqual(-1, qemu_io('-f', 'raw', '-c', 'read -P 0xab 0 524288', backing_img).find("verification failed"))
-        self.assertEqual(-1, qemu_io('-f', 'raw', '-c', 'read -P 0xef 524288 524288', backing_img).find("verification failed"))
+        qemu_io('-f', 'raw', '-c', 'read -P 0xab 0 524288', backing_img)
+        qemu_io('-f', 'raw', '-c', 'read -P 0xef 524288 524288', backing_img)
 
     def test_top_and_base_reversed(self):
         self.assert_no_active_block_jobs()
 
     def test_commit(self):
         self.run_commit_test(self.mid_img, self.backing_img)
-        self.assertEqual(-1, qemu_io('-f', 'raw', '-c', 'read -P 0xab 0 524288', self.backing_img_abs).find("verification failed"))
-        self.assertEqual(-1, qemu_io('-f', 'raw', '-c', 'read -P 0xef 524288 524288', self.backing_img_abs).find("verification failed"))
+        qemu_io('-f', 'raw', '-c', 'read -P 0xab 0 524288', self.backing_img_abs)
+        qemu_io('-f', 'raw', '-c', 'read -P 0xef 524288 524288', self.backing_img_abs)
 
     def test_device_not_found(self):
         result = self.vm.qmp('block-commit', device='nonexistent', top='%s' % self.mid_img)
 
     def test_top_is_active(self):
         self.run_commit_test(self.test_img, self.backing_img)
-        self.assertEqual(-1, qemu_io('-f', 'raw', '-c', 'read -P 0xab 0 524288', self.backing_img_abs).find("verification failed"))
-        self.assertEqual(-1, qemu_io('-f', 'raw', '-c', 'read -P 0xef 524288 524288', self.backing_img_abs).find("verification failed"))
+        qemu_io('-f', 'raw', '-c', 'read -P 0xab 0 524288', self.backing_img_abs)
+        qemu_io('-f', 'raw', '-c', 'read -P 0xef 524288 524288', self.backing_img_abs)
 
     def test_top_and_base_reversed(self):
         self.assert_no_active_block_jobs()
 
     def do_test_io(self, read_or_write):
         for index, pattern_file in enumerate(self.pattern_files):
-            result = qemu_io('-f', iotests.imgfmt,
-                             '-c',
-                             f'{read_or_write} -P {index + 1} {index}M 1M',
-                             pattern_file)
-            self.assertFalse('Pattern verification failed' in result)
+            qemu_io('-f', iotests.imgfmt,
+                    '-c',
+                    f'{read_or_write} -P {index + 1} {index}M 1M',
+                    pattern_file)
 
     @iotests.skip_if_unsupported(['throttle'])
     def setUp(self):