Added 2 missing testcases for Keras switch backend

tensorflow/python/keras/backend_test.py

@@ -1880,5 +1880,37 @@ def test_get_session_different_graphs(self):
       self.assertIsNot(session, keras.backend.get_session())
 
 
+@test_util.run_all_in_graph_and_eager_modes
+class ControlOpsTests(test.TestCase):
+
+  def test_function_switch_basics(self):
+    x = array_ops.constant(2.0)
+    y = array_ops.constant(3.0)
+
+    def xpowy():
+      return keras.backend.pow(x, y)
+    def ypowx():
+      return keras.backend.pow(y, x)
+
+    tensor = keras.backend.switch(keras.backend.less(x, y), xpowy, ypowx)
+    self.assertEqual(keras.backend.eval(tensor), [8.0])
+
+    tensor = keras.backend.switch(keras.backend.greater(x, y), xpowy, ypowx)
+    self.assertEqual(keras.backend.eval(tensor), [9.0])
+
+  def test_unequal_rank(self):
+    x = ops.convert_to_tensor(np.array([[1, 2, 3], [4, 5, 6]]),
+                              dtype='float32')
+    y = ops.convert_to_tensor(np.array([1, 2, 3]), dtype='float32')
+    def true_func():
+      return x
+
+    def false_func():
+      return y
+
+    with self.assertRaisesRegexp(ValueError, "Rank of `condition` should be less than"):
+      keras.backend.switch(keras.backend.equal(x, x), false_func, true_func)
+
+
 if __name__ == '__main__':
   test.main()