test: Add delay for time-related arm64 tests (#138)

The tests on GitHub run on x86 instances (because arm64 instances don't
have Docker installed) so when running the arm64 tests, invokes take
longer because of the cross-architecture emulation. This caused that
some tests that check remaining time in the function were not landing
on the correct time range.

It's unknown why this delay started manifesting more consistently, we might
want to find a better solution in the future.

test/integration/local_lambda/test_end_to_end.py

@@ -173,9 +173,8 @@ def test_context_get_remaining_time_in_three_seconds(self):
         with self.create_container(params, image):
             r = self.invoke_function()
 
-            # Execution time is not decided, 1.0s ~ 3.0s is a good estimation
-            self.assertLess(int(r.content), 3000)
-            self.assertGreater(int(r.content), 1000)
+            # Execution time is not decided, but it should be around 2.0s
+            self.assertAround(int(r.content), 2000)
 
 
     def test_context_get_remaining_time_in_ten_seconds(self):
@@ -186,9 +185,8 @@ def test_context_get_remaining_time_in_ten_seconds(self):
         with self.create_container(params, image):
             r = self.invoke_function()
 
-            # Execution time is not decided, 8.0s ~ 10.0s is a good estimation
-            self.assertLess(int(r.content), 10000)
-            self.assertGreater(int(r.content), 8000)
+            # Execution time is not decided, but it should be around 9.0s
+            self.assertAround(int(r.content), 9000)
 
 
     def test_context_get_remaining_time_in_default_deadline(self):
@@ -199,9 +197,8 @@ def test_context_get_remaining_time_in_default_deadline(self):
         with self.create_container(params, image):
             r = self.invoke_function()
 
-            # Executation time is not decided, 298.0s ~ 300.0s is a good estimation
-            self.assertLess(int(r.content), 300000)
-            self.assertGreater(int(r.content), 298000)
+            # Execution time is not decided, but it should be around 299.0s
+            self.assertAround(int(r.content), 299000)
 
 
     def test_invoke_with_pre_runtime_api_runtime(self):
@@ -256,6 +253,13 @@ def test_custom_client_context(self):
             self.assertEqual("bar", content["foo"])
             self.assertEqual(123, content["baz"])
 
+    def assertAround(self, number, target):
+        # Emulating arm64 on x86 causes the invoke to take longer
+        delay_arm64 = 500
+        actual_target = target if self.ARCH != 'arm64' else target - delay_arm64
+
+        self.assertLess(number, actual_target + 1000)
+        self.assertGreater(number, actual_target - 1000)
 
 if __name__ == "__main__":
     main()