fix(mcp): Handle big_number charts and make semantic warnings non-blocking (#37142)

Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>

tests/unit_tests/mcp_service/chart/tool/test_get_chart_data.py

@@ -16,7 +16,7 @@
 # under the License.
 
 """
-Tests for the get_chart_data request schema
+Tests for the get_chart_data request schema and big_number chart handling.
 """
 
 import pytest
@@ -24,6 +24,134 @@ import pytest
 from superset.mcp_service.chart.schemas import GetChartDataRequest
 
 
+class TestBigNumberChartFallback:
+    """Tests for big_number chart fallback query construction."""
+
+    def test_big_number_uses_singular_metric(self):
+        """Test that big_number charts use 'metric' (singular) from form_data."""
+        # Mock form_data for big_number chart
+        form_data = {
+            "metric": {"label": "Count", "expressionType": "SIMPLE", "column": None},
+            "viz_type": "big_number",
+        }
+
+        # Verify the metric extraction logic
+        metric = form_data.get("metric")
+        metrics = [metric] if metric else []
+
+        assert len(metrics) == 1
+        assert metrics[0]["label"] == "Count"
+
+    def test_big_number_total_uses_singular_metric(self):
+        """Test that big_number_total charts use 'metric' (singular)."""
+        form_data = {
+            "metric": {"label": "Total Sales", "expressionType": "SQL"},
+            "viz_type": "big_number_total",
+        }
+
+        metric = form_data.get("metric")
+        metrics = [metric] if metric else []
+
+        assert len(metrics) == 1
+        assert metrics[0]["label"] == "Total Sales"
+
+    def test_big_number_empty_metric_returns_empty_list(self):
+        """Test handling of big_number chart with no metric configured."""
+        form_data = {
+            "metric": None,
+            "viz_type": "big_number",
+        }
+
+        metric = form_data.get("metric")
+        metrics = [metric] if metric else []
+
+        assert len(metrics) == 0
+
+    def test_big_number_no_groupby_columns(self):
+        """Test that big_number charts don't have groupby columns."""
+        form_data = {
+            "metric": {"label": "Count"},
+            "viz_type": "big_number",
+            "groupby": ["should_be_ignored"],  # This should be ignored
+        }
+
+        viz_type = form_data.get("viz_type", "")
+        if viz_type.startswith("big_number"):
+            groupby_columns: list[str] = []  # big_number charts don't group by
+        else:
+            groupby_columns = form_data.get("groupby", [])
+
+        assert groupby_columns == []
+
+    def test_standard_chart_uses_plural_metrics(self):
+        """Test that non-big_number charts use 'metrics' (plural)."""
+        form_data = {
+            "metrics": [
+                {"label": "Sum of Sales"},
+                {"label": "Avg of Quantity"},
+            ],
+            "groupby": ["region", "category"],
+            "viz_type": "table",
+        }
+
+        viz_type = form_data.get("viz_type", "")
+        if viz_type.startswith("big_number"):
+            metric = form_data.get("metric")
+            metrics = [metric] if metric else []
+            groupby_columns: list[str] = []
+        else:
+            metrics = form_data.get("metrics", [])
+            groupby_columns = form_data.get("groupby", [])
+
+        assert len(metrics) == 2
+        assert len(groupby_columns) == 2
+
+    def test_viz_type_detection_for_single_metric_charts(self):
+        """Test viz_type detection handles all single-metric chart types."""
+        # Chart types that use "metric" (singular) instead of "metrics" (plural)
+        single_metric_types = ("big_number", "pop_kpi")
+
+        # big_number variants match via startswith
+        big_number_types = ["big_number", "big_number_total"]
+        for viz_type in big_number_types:
+            is_single_metric = (
+                viz_type.startswith("big_number") or viz_type in single_metric_types
+            )
+            assert is_single_metric is True
+
+        # pop_kpi (BigNumberPeriodOverPeriod) matches via exact match
+        assert "pop_kpi" in single_metric_types
+
+        # Verify standard chart types don't match
+        other_types = ["table", "line", "bar", "pie", "echarts_timeseries"]
+        for viz_type in other_types:
+            is_single_metric = (
+                viz_type.startswith("big_number") or viz_type in single_metric_types
+            )
+            assert is_single_metric is False
+
+    def test_pop_kpi_uses_singular_metric(self):
+        """Test that pop_kpi (BigNumberPeriodOverPeriod) uses singular metric."""
+        form_data = {
+            "metric": {"label": "Period Comparison", "expressionType": "SQL"},
+            "viz_type": "pop_kpi",
+        }
+
+        viz_type = form_data.get("viz_type", "")
+        single_metric_types = ("big_number", "pop_kpi")
+        if viz_type.startswith("big_number") or viz_type in single_metric_types:
+            metric = form_data.get("metric")
+            metrics = [metric] if metric else []
+            groupby_columns: list[str] = []
+        else:
+            metrics = form_data.get("metrics", [])
+            groupby_columns = form_data.get("groupby", [])
+
+        assert len(metrics) == 1
+        assert metrics[0]["label"] == "Period Comparison"
+        assert groupby_columns == []
+
+
 class TestGetChartDataRequestSchema:
     """Test the GetChartDataRequest schema validation."""