Check TensorRT error message more granularly (#5719)

* Check TRT err msg more granularly

* Clarify source of error messages

* Consolidate tests for message parts

qa/L0_trt_error_propagation/trt_error_propagation_test.py

@@ -40,12 +40,17 @@ def test_invalid_trt_model(self):
         with self.assertRaises(InferenceServerException) as cm:
             self.__triton.load_model("invalid_plan_file")
         err_msg = str(cm.exception)
-        self.assertIn("Internal: unable to create TensorRT engine", err_msg,
-                      "Caught an unexpected exception")
-        self.assertIn(
-            "Error Code 4: Internal Error (Engine deserialization failed.)",
-            err_msg,
-            "Detailed error message not propagated back to triton client")
+        # All 'expected_msg_parts' should be present in the 'err_msg' in order
+        expected_msg_parts = [
+            "load failed for model", "version 1 is at UNAVAILABLE state: ",
+            "Internal: unable to create TensorRT engine: ", "Error Code ",
+            "Internal Error "
+        ]
+        for expected_msg_part in expected_msg_parts:
+            self.assertIn(
+                expected_msg_part, err_msg,
+                "Cannot find an expected part of error message")
+            _, err_msg = err_msg.split(expected_msg_part)
 
     def test_invalid_trt_model_autocomplete(self):
         with self.assertRaises(InferenceServerException) as cm: