Addition of delta keyword argument to unittest.TestCase.assertAlmostEquals and assertNotAlmostEquals

This allows the comparison of objects by specifying a maximum difference; this includes the comparing of non-numeric objects that don't support rounding.

Lib/unittest/test/test_assertions.py

@@ -1,3 +1,5 @@
+import datetime
+
 import unittest
 
 
@@ -25,6 +27,28 @@ class Test_Assertions(unittest.TestCase):
         self.assertRaises(self.failureException, self.assertNotAlmostEqual,
                           float('inf'), float('inf'))
 
+    def test_AmostEqualWithDelta(self):
+        self.assertAlmostEqual(1.1, 1.0, delta=0.5)
+        self.assertAlmostEqual(1.0, 1.1, delta=0.5)
+        self.assertNotAlmostEqual(1.1, 1.0, delta=0.05)
+        self.assertNotAlmostEqual(1.0, 1.1, delta=0.05)
+
+        self.assertRaises(self.failureException, self.assertAlmostEqual,
+                          1.1, 1.0, delta=0.05)
+        self.assertRaises(self.failureException, self.assertNotAlmostEqual,
+                          1.1, 1.0, delta=0.5)
+
+        self.assertRaises(TypeError, self.assertAlmostEqual,
+                          1.1, 1.0, places=2, delta=2)
+        self.assertRaises(TypeError, self.assertNotAlmostEqual,
+                          1.1, 1.0, places=2, delta=2)
+
+        first = datetime.datetime.now()
+        second = first + datetime.timedelta(seconds=10)
+        self.assertAlmostEqual(first, second,
+                               delta=datetime.timedelta(seconds=20))
+        self.assertNotAlmostEqual(first, second,
+                                  delta=datetime.timedelta(seconds=5))
 
     def test_assertRaises(self):
         def _raise(e):