diff --git a/Tests/test_decompression_bomb.py b/Tests/test_decompression_bomb.py
index 53c8bb5e6..1f85b1b9a 100644
--- a/Tests/test_decompression_bomb.py
+++ b/Tests/test_decompression_bomb.py
@@ -1,37 +1,40 @@
-from tester import *
+from helper import unittest, PillowTestCase, tearDownModule
 
 from PIL import Image
 
 test_file = "Images/lena.ppm"
 
 
-def test_no_warning_small_file():
-    # Implicit assert: no warning.
-    # A warning would cause a failure.
-    Image.open(test_file)
+class TestDecompressionBomb(PillowTestCase):
 
+    def test_no_warning_small_file(self):
+        # Implicit assert: no warning.
+        # A warning would cause a failure.
+        Image.open(test_file)
 
-def test_no_warning_no_limit():
-    # Arrange
-    # Turn limit off
-    Image.MAX_IMAGE_PIXELS = None
-    assert_equal(Image.MAX_IMAGE_PIXELS, None)
+    def test_no_warning_no_limit(self):
+        # Arrange
+        # Turn limit off
+        Image.MAX_IMAGE_PIXELS = None
+        self.assertEqual(Image.MAX_IMAGE_PIXELS, None)
 
-    # Act / Assert
-    # Implicit assert: no warning.
-    # A warning would cause a failure.
-    Image.open(test_file)
+        # Act / Assert
+        # Implicit assert: no warning.
+        # A warning would cause a failure.
+        Image.open(test_file)
 
+    def test_warning(self):
+        # Arrange
+        # Set limit to a low, easily testable value
+        Image.MAX_IMAGE_PIXELS = 10
+        self.assertEqual(Image.MAX_IMAGE_PIXELS, 10)
 
-def test_warning():
-    # Arrange
-    # Set limit to a low, easily testable value
-    Image.MAX_IMAGE_PIXELS = 10
-    assert_equal(Image.MAX_IMAGE_PIXELS, 10)
+        # Act / Assert
+        self.assert_warning(
+            Image.DecompressionBombWarning,
+            lambda: Image.open(test_file))
 
-    # Act / Assert
-    assert_warning(
-        DecompressionBombWarning,
-        lambda: Image.open(test_file))
+if __name__ == '__main__':
+    unittest.main()
 
 # End of file