Add tests for round functions

tests/snippets/builtin_round.py

@@ -1,4 +1,21 @@
-assert round(0.0, 0) == 0.0
+from testutils import assertRaises
+
+assert round(0) == 0
+assert isinstance(round(0), int)
+assert round(0.0) == 0
+assert isinstance(round(0.0), int)
+
+assert round(0, None) == 0
+assert isinstance(round(0, None), int)
+assert round(0.0, None) == 0
+assert isinstance(round(0, None), int)
+
 assert round(0, 0) == 0
+assert isinstance(round(0, 0), int)
+assert round(0.0, 0) == 0.0  # Cannot check the type
+assert isinstance(round(0.0, 0), float)
+
 with assertRaises(TypeError):
-    round(0, 0.0)
+    round(0, 0.0)
+with assertRaises(TypeError):
+    round(0.0, 0.0)

tests/snippets/floats.py

@@ -163,6 +163,8 @@ assert isinstance(0.5.__round__(None), int)
 assert isinstance(1.5.__round__(None), int)
 assert 0.5.__round__(None) == 0
 assert 1.5.__round__(None) == 2
+assert_raises(TypeError, lambda: 0.5.__round__(0.0))
+assert_raises(TypeError, lambda: 1.5.__round__(0.0))
 assert_raises(OverflowError, float('inf').__round__)
 assert_raises(ValueError, float('nan').__round__)
 

tests/snippets/ints.py

@@ -139,3 +139,16 @@ class F(float):
         return 3
 
 assert int(F(1.2)) == 3
+
+assert isinstance((0).__round__(), int)
+assert isinstance((1).__round__(), int)
+assert (0).__round__() == 0
+assert (1).__round__() == 1
+assert isinstance((0).__round__(0), int)
+assert isinstance((1).__round__(0), int)
+assert (0).__round__(0) == 0
+assert (1).__round__(0) == 1
+assert_raises(TypeError, lambda: (0).__round__(None))
+assert_raises(TypeError, lambda: (1).__round__(None))
+assert_raises(TypeError, lambda: (0).__round__(0.0))
+assert_raises(TypeError, lambda: (1).__round__(0.0))