Added test_1_7 test case from leiden oefenopgaves.

tests/test_leiden_oefenopgave.py

@@ -89,6 +89,21 @@ class TestLeidenOefenopgave(TestCase):
         self.assertRewrite(['(2x + x)x', '(2 + 1)xx', '3xx',
                             '3 * x ^ (1 + 1)', '3 * x ^ 2'])
 
+    def test_1_7(self):
+        self.assertRewrite(['(4x + 5) * -(5 - 4x)',
+                            '(4x + 5)(-5 - -4x)',
+                            '(4x + 5)(-5 + 4x)',
+                            '4x * -5 + 4x * 4x + 5 * -5 + 5 * 4x',
+                            '-20x + 4x * 4x + 5 * -5 + 5 * 4x',
+                            '-20x + 16xx + 5 * -5 + 5 * 4x',
+                            '-20x + 16 * x ^ (1 + 1) + 5 * -5 + 5 * 4x',
+                            '-20x + 16 * x ^ 2 + 5 * -5 + 5 * 4x',
+                            '-20x + 16 * x ^ 2 - 25 + 5 * 4x',
+                            '-20x + 16 * x ^ 2 - 25 + 20x',
+                            '(-20 + 20)x + 16 * x ^ 2 - 25',
+                            '0x + 16 * x ^ 2 - 25',])
+                            # FIXME: '16x^2 - 25'])
+
     def test_2(self):
         pass