feat(mcp): add get_chart_type_schema tool for on-demand schema discovery (#39142)

(cherry picked from commit 5f9fc31ae2)

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

@@ -0,0 +1,86 @@
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+
+"""Tests for get_chart_type_schema tool logic."""
+
+import pytest
+
+from superset.mcp_service.chart.tool.get_chart_type_schema import (
+    _CHART_EXAMPLES,
+    _get_chart_type_schema_impl as _call_schema,
+    VALID_CHART_TYPES,
+)
+
+
+class TestGetChartTypeSchema:
+    @pytest.mark.parametrize("chart_type", VALID_CHART_TYPES)
+    def test_valid_chart_type_returns_schema(self, chart_type: str) -> None:
+        result = _call_schema(chart_type)
+        assert "schema" in result
+        assert result["chart_type"] == chart_type
+        assert isinstance(result["schema"], dict)
+        assert "properties" in result["schema"]
+        assert "examples" in result
+
+    def test_xy_schema_has_expected_fields(self) -> None:
+        result = _call_schema("xy")
+        props = result["schema"]["properties"]
+        assert "x" in props
+        assert "y" in props
+        assert "kind" in props
+
+    def test_table_schema_has_columns(self) -> None:
+        result = _call_schema("table")
+        props = result["schema"]["properties"]
+        assert "columns" in props
+
+    def test_pie_schema_has_dimension_metric(self) -> None:
+        result = _call_schema("pie")
+        props = result["schema"]["properties"]
+        assert "dimension" in props
+        assert "metric" in props
+
+    def test_big_number_schema_has_metric(self) -> None:
+        result = _call_schema("big_number")
+        props = result["schema"]["properties"]
+        assert "metric" in props
+
+    def test_include_examples_false_omits_examples(self) -> None:
+        result = _call_schema("xy", include_examples=False)
+        assert "schema" in result
+        assert "examples" not in result
+
+    def test_invalid_chart_type_returns_error(self) -> None:
+        result = _call_schema("nonexistent")
+        assert "error" in result
+        assert "valid_chart_types" in result
+        assert result["valid_chart_types"] == VALID_CHART_TYPES
+
+    def test_examples_match_chart_type(self) -> None:
+        result = _call_schema("pie")
+        for example in result["examples"]:
+            assert example["chart_type"] == "pie"
+
+    def test_valid_chart_types_constant(self) -> None:
+        assert len(VALID_CHART_TYPES) == 7
+        assert "xy" in VALID_CHART_TYPES
+        assert "table" in VALID_CHART_TYPES
+
+    def test_all_chart_types_have_examples(self) -> None:
+        for chart_type in VALID_CHART_TYPES:
+            assert chart_type in _CHART_EXAMPLES
+            assert len(_CHART_EXAMPLES[chart_type]) >= 1