fix(metrics): Add more validation to check missing metrics

validate_missing_metrics is actually just validating the jsonschema
library and not any Firecracker property itself which is fine since
it is kind of a reassurance that it is working as we expect it to.
However, atm it only checks if jsonschema throws an exception on
the missing metrics and it should in fact also check if there was an
exception raised at all. If for some reason jsonschema doesn't raise
an exception then the test passes and the purpose of this function is
defeated.
So, raise exception if jsonschema doesn't raise one.

Signed-off-by: Sudan Landge <[email protected]>

tests/host_tools/fcmetrics.py

@@ -14,6 +14,7 @@
 from threading import Thread
 
 import jsonschema
+import pytest
 
 
 def validate_fc_metrics(metrics):
@@ -283,38 +284,28 @@ def validate_missing_metrics(metrics):
         # remove some metrics and confirm that fields and not just top level metrics
         # are validated.
         temp_pop_metrics = metrics["api_server"].pop("process_startup_time_us")
-        try:
+        with pytest.raises(
+            jsonschema.ValidationError,
+            match="'process_startup_time_us' is a required property",
+        ):
             jsonschema.validate(instance=metrics, schema=firecracker_metrics_schema)
-        except jsonschema.exceptions.ValidationError as error:
-            if (
-                error.message.strip()
-                == "'process_startup_time_us' is a required property"
-            ):
-                pass
-            else:
-                raise error
         metrics["api_server"]["process_startup_time_us"] = temp_pop_metrics
 
         if platform.machine() == "aarch64":
             temp_pop_metrics = metrics["rtc"].pop("error_count")
-            try:
+            with pytest.raises(
+                jsonschema.ValidationError, match="'error_count' is a required property"
+            ):
                 jsonschema.validate(instance=metrics, schema=firecracker_metrics_schema)
-            except jsonschema.exceptions.ValidationError as error:
-                if error.message.strip() == "'error_count' is a required property":
-                    pass
-                else:
-                    raise error
             metrics["rtc"]["error_count"] = temp_pop_metrics
 
         for vhost_user_dev in vhost_user_devices:
             temp_pop_metrics = metrics[vhost_user_dev].pop("activate_time_us")
-            try:
+            with pytest.raises(
+                jsonschema.ValidationError,
+                match="'activate_time_us' is a required property",
+            ):
                 jsonschema.validate(instance=metrics, schema=firecracker_metrics_schema)
-            except jsonschema.exceptions.ValidationError as error:
-                if error.message.strip() == "'activate_time_us' is a required property":
-                    pass
-                else:
-                    raise error
             metrics[vhost_user_dev]["activate_time_us"] = temp_pop_metrics
 
     validate_missing_metrics(metrics)