fix(alerts): void query with numeric comparison (#13090)

* fix(alerts): void query with numeric comparison

* remove config changes

* fix tests

* better logic

* fix logic

* fix logic

* Improve test readability

superset/reports/commands/alert.py

@@ -47,15 +47,16 @@ class AlertCommand(BaseCommand):
     def run(self) -> bool:
         self.validate()
 
-        if self._report_schedule.validator_type == ReportScheduleValidatorType.NOT_NULL:
+        if self._is_validator_not_null:
             self._report_schedule.last_value_row_json = str(self._result)
-            return self._result not in (0, None, np.nan)
+            return self._result is not None
         self._report_schedule.last_value = self._result
         try:
             operator = json.loads(self._report_schedule.validator_config_json)["op"]
             threshold = json.loads(self._report_schedule.validator_config_json)[
                 "threshold"
             ]
+
             return OPERATOR_FUNCTIONS[operator](self._result, threshold)
         except (KeyError, json.JSONDecodeError):
             raise AlertValidatorConfigError()
@@ -95,6 +96,18 @@ class AlertCommand(BaseCommand):
         except (AssertionError, TypeError, ValueError):
             raise AlertQueryInvalidTypeError()
 
+    @property
+    def _is_validator_not_null(self) -> bool:
+        return (
+            self._report_schedule.validator_type == ReportScheduleValidatorType.NOT_NULL
+        )
+
+    @property
+    def _is_validator_operator(self) -> bool:
+        return (
+            self._report_schedule.validator_type == ReportScheduleValidatorType.OPERATOR
+        )
+
     def validate(self) -> None:
         """
         Validate the query result as a Pandas DataFrame
@@ -108,10 +121,14 @@ class AlertCommand(BaseCommand):
         except Exception as ex:
             raise AlertQueryError(message=str(ex))
 
-        if df.empty:
+        if df.empty and self._is_validator_not_null:
+            self._result = None
+            return
+        if df.empty and self._is_validator_operator:
+            self._result = 0.0
             return
         rows = df.to_records()
-        if self._report_schedule.validator_type == ReportScheduleValidatorType.NOT_NULL:
+        if self._is_validator_not_null:
             self._validate_not_null(rows)
             return
         self._validate_operator(rows)

tests/reports/commands_tests.py

@@ -308,7 +308,7 @@ def create_test_table_context(database: Database):
 
 
 @pytest.yield_fixture(
-    params=["alert1", "alert2", "alert3", "alert4", "alert5", "alert6"]
+    params=["alert1", "alert2", "alert3", "alert4", "alert5", "alert6", "alert7"]
 )
 def create_no_alert_email_chart(request):
     param_config = {
@@ -338,10 +338,15 @@ def create_no_alert_email_chart(request):
             "validator_config_json": '{"op": "!=", "threshold": 10}',
         },
         "alert6": {
-            "sql": "SELECT first from test_table where first=0",
+            "sql": "SELECT first from test_table where 1=0",
             "validator_type": ReportScheduleValidatorType.NOT_NULL,
             "validator_config_json": "{}",
         },
+        "alert7": {
+            "sql": "SELECT first from test_table where 1=0",
+            "validator_type": ReportScheduleValidatorType.OPERATOR,
+            "validator_config_json": '{"op": ">", "threshold": 0}',
+        },
     }
     with app.app_context():
         chart = db.session.query(Slice).first()