add tests to improve coverage for test_complex_special

Author: Aniketsy

Lib/test/test_cmath.py

@@ -2,6 +2,7 @@
 from test.support.testcase import ComplexesAreIdenticalMixin
 from test.test_math import parse_testfile, test_file
 import test.test_math as test_math
+import itertools
 import unittest
 import cmath, math
 from cmath import phase, polar, rect, pi
@@ -590,25 +591,22 @@ def test_complex_special(self):
         self.assertIsNotClose(-INF, INF)
         self.assertIsNotClose(0, INF)
         self.assertIsNotClose(0, INF*1j)
-        self.assertIsNotClose(complex(INF, INF), complex(-INF, -INF))
-        self.assertIsNotClose(complex(INF, INF), complex(INF, -INF))
-        self.assertIsNotClose(complex(INF, INF), complex(-INF, INF))
-        self.assertIsNotClose(complex(-INF, INF), complex(INF, -INF))
-        self.assertIsNotClose(complex(NAN, NAN), complex(NAN, NAN))
-        self.assertIsNotClose(complex(NAN, 0), complex(NAN, 0))
-        self.assertIsNotClose(complex(0, NAN), complex(0, NAN))
-        self.assertIsNotClose(complex(INF, NAN), complex(INF, NAN))
-        self.assertIsNotClose(complex(NAN, INF), complex(NAN, INF))
-        self.assertIsNotClose(complex(-INF, NAN), complex(-INF, NAN))
-        self.assertIsNotClose(complex(NAN, -INF), complex(NAN, -INF))
-        self.assertIsNotClose(complex(INF, INF), complex(1, 1))
-        self.assertIsNotClose(complex(-INF, -INF), complex(1, 1))
-        self.assertIsNotClose(complex(INF, 0), complex(0, 0))
-        self.assertIsNotClose(complex(0, INF), complex(0, 0))
-        self.assertIsClose(complex(INF, INF), complex(INF, INF))
-        self.assertIsClose(complex(-INF, -INF), complex(-INF, -INF))
-        self.assertIsClose(complex(INF, -INF), complex(INF, -INF))
-        self.assertIsClose(complex(-INF, INF), complex(-INF, INF))
+        special = [INF, -INF, NAN]
+        special_complex = [complex(x, y) for x in special for y in special]
+
+        nan_complex = [c for c in special_complex
+                      if math.isnan(c.real) or math.isnan(c.imag)]
+        for z in nan_complex:
+            for w in special_complex:
+                self.assertIsNotClose(z, w)
+
+        inf_complex = [c for c in special_complex
+                      if not math.isnan(c.real) and not math.isnan(c.imag)]
+        for z, w in itertools.combinations(inf_complex, 2):
+            self.assertIsNotClose(z, w)
+
+        for z in inf_complex:
+            self.assertIsClose(z, z)
 
 
 if __name__ == "__main__":