Updated tests

Tests/test_imagegrab.py

@@ -1,3 +1,4 @@
+import pytest
 import subprocess
 import sys
 
@@ -36,23 +37,19 @@ def test_grab_x11(self):
     @unittest.skipIf(Image.core.HAVE_XCB, "tests missing XCB")
     def test_grab_no_xcb(self):
         if sys.platform not in ("win32", "darwin"):
-            with self.assertRaises(IOError) as e:
+            with pytest.raises(IOError) as e:
                 ImageGrab.grab()
-            self.assertTrue(
-                str(e.exception).startswith("Pillow was built without XCB support")
-            )
+            assert str(e.value).startswith("Pillow was built without XCB support")
 
-        with self.assertRaises(IOError) as e:
+        with pytest.raises(IOError) as e:
             ImageGrab.grab(xdisplay="")
-        self.assertTrue(
-            str(e.exception).startswith("Pillow was built without XCB support")
-        )
+        assert str(e.value).startswith("Pillow was built without XCB support")
 
     @unittest.skipUnless(Image.core.HAVE_XCB, "requires XCB")
     def test_grab_invalid_xdisplay(self):
-        with self.assertRaises(IOError) as e:
+        with pytest.raises(IOError) as e:
             ImageGrab.grab(xdisplay="error.test:0.0")
-        assert str(e.exception).startswith("X connection failed")
+        assert str(e.value).startswith("X connection failed")
 
     def test_grabclipboard(self):
         if sys.platform == "darwin":
@@ -67,11 +64,9 @@ def test_grabclipboard(self):
             )
             p.communicate()
         else:
-            with self.assertRaises(NotImplementedError) as e:
+            with pytest.raises(NotImplementedError) as e:
                 ImageGrab.grabclipboard()
-            self.assertEqual(
-                str(e.exception), "ImageGrab.grabclipboard() is macOS and Windows only"
-            )
+            assert str(e.value) == "ImageGrab.grabclipboard() is macOS and Windows only"
             return
 
         im = ImageGrab.grabclipboard()