diff --git a/tests/unit/gapic/test_method.py b/tests/unit/gapic/test_method.py
index 927902bf0..29e8fc217 100644
--- a/tests/unit/gapic/test_method.py
+++ b/tests/unit/gapic/test_method.py
@@ -192,6 +192,7 @@ def test_wrap_method_with_overriding_retry_timeout_compression(unused_sleep):
     )
 
 
+@pytest.mark.skip(reason="Known flaky due to floating point comparison. #866")
 def test_wrap_method_with_overriding_timeout_as_a_number():
     method = mock.Mock(spec=["__call__"], return_value=42)
     default_retry = retry.Retry()
@@ -200,6 +201,8 @@ def test_wrap_method_with_overriding_timeout_as_a_number():
         method, default_retry, default_timeout
     )
 
+    # Using "result = wrapped_method(timeout=22)" fails since wrapped_method
+    # does floating point calculations that results in 21.987.. instead of 22
     result = wrapped_method(timeout=22)
 
     assert result == 42
@@ -210,6 +213,24 @@ def test_wrap_method_with_overriding_timeout_as_a_number():
     assert actual_timeout == pytest.approx(22, abs=0.01)
 
 
+def test_wrap_method_with_overriding_constant_timeout():
+    method = mock.Mock(spec=["__call__"], return_value=42)
+    default_retry = retry.Retry()
+    default_timeout = timeout.ConstantTimeout(60)
+    wrapped_method = google.api_core.gapic_v1.method.wrap_method(
+        method, default_retry, default_timeout
+    )
+
+    result = wrapped_method(timeout=timeout.ConstantTimeout(22))
+
+    assert result == 42
+
+    actual_timeout = method.call_args[1]["timeout"]
+    metadata = method.call_args[1]["metadata"]
+    assert metadata == mock.ANY
+    assert actual_timeout == 22
+
+
 def test_wrap_method_with_call():
     method = mock.Mock()
     mock_call = mock.Mock()
diff --git a/tests/unit/gapic/test_routing_header.py b/tests/unit/gapic/test_routing_header.py
index 2c8c75469..f0ec82ec6 100644
--- a/tests/unit/gapic/test_routing_header.py
+++ b/tests/unit/gapic/test_routing_header.py
@@ -90,8 +90,8 @@ def test__urlencode_param(key, value, expected):
 def test__urlencode_param_caching_performance():
     import time
 
-    key = "key" * 100
-    value = "value" * 100
+    key = "key" * 10000
+    value = "value" * 10000
     # time with empty cache
     start_time = time.perf_counter()
     routing_header._urlencode_param(key, value)