Added the unit test for metadata_service

changelog_entry.yaml

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+### Added
+- Added the unit test for metadata_service.py

tests/unit/services/test_metadata_service.py

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+import pytest
+from policyengine_api.services.metadata_service import MetadataService
+from policyengine_api.country import COUNTRIES
+
+class TestMetadataService:
+    @pytest.fixture
+    def service(self):
+        return MetadataService()
+
+    def test_get_metadata_success(self, service, test_db):
+        # GIVEN a valid country ID
+        country_id = "uk"
+
+        # WHEN we call get_metadata
+        result = service.get_metadata(country_id)
+
+        # THEN it should return the country's metadata
+        assert result is not None
+        assert isinstance(result, dict)
+        # Verify all required metadata fields are present
+        assert "variables" in result
+        assert "parameters" in result
+        assert "entities" in result
+        assert "variableModules" in result
+        assert "economy_options" in result
+        assert "current_law_id" in result
+        assert "basicInputs" in result
+        assert "modelled_policies" in result
+        assert "version" in result
+
+        # Verify some UK-specific data
+        assert result["current_law_id"] == 1
+        uk_regions = result["economy_options"]["region"]
+        assert any(region["name"] == "uk" for region in uk_regions)
+        assert any(region["name"] == "eng" for region in uk_regions)
+        assert any(region["name"] == "scot" for region in uk_regions)
+
+    def test_get_metadata_nonexistent_country(self, service, test_db):
+        # GIVEN a non-existent country ID
+        invalid_country_id = "invalid_country"
+
+        # WHEN we call get_metadata with an invalid country
+        # THEN it should raise a RuntimeError with appropriate message
+        with pytest.raises(RuntimeError) as exc_info:
+            service.get_metadata(invalid_country_id)
+
+        assert str(exc_info.value) == f"Attempted to get metadata for a nonexistant country: '{invalid_country_id}'"
+
+    def test_get_metadata_empty_country_id(self, service, test_db):
+        # GIVEN an empty country ID
+        empty_country_id = ""
+
+        # WHEN we call get_metadata with an empty country ID
+        # THEN it should raise a RuntimeError
+        with pytest.raises(RuntimeError) as exc_info:
+            service.get_metadata(empty_country_id)
+
+        assert str(exc_info.value) == f"Attempted to get metadata for a nonexistant country: '{empty_country_id}'"
+
+    def test_get_metadata_all_supported_countries(self, service, test_db):
+        # GIVEN all supported country IDs
+        supported_countries = ["uk", "us", "ca", "ng", "il"]
+
+        # WHEN we try to get metadata for each supported country
+        for country_id in supported_countries:
+            metadata = service.get_metadata(country_id)
+
+            # THEN it should return valid metadata for each country
+            assert metadata is not None
+            assert isinstance(metadata, dict)
+
+            # Verify basic structure
+            assert "variables" in metadata
+            assert "parameters" in metadata
+            assert "entities" in metadata
+            assert "current_law_id" in metadata
+
+            # Verify country-specific data
+            country_id_mapping = {
+                "uk": 1,
+                "us": 2,
+                "ca": 3,
+                "ng": 4,
+                "il": 5
+            }
+            assert metadata["current_law_id"] == country_id_mapping[country_id]
+
+            # Verify region data exists
+            assert "economy_options" in metadata
+            assert "region" in metadata["economy_options"]
+            regions = metadata["economy_options"]["region"]
+            assert any(region["name"] == country_id for region in regions)
+
+            # Verify time periods exist
+            assert "time_period" in metadata["economy_options"]
+            assert len(metadata["economy_options"]["time_period"]) > 0
+
+    def test_get_metadata_verify_uk_specific_data(self, service, test_db):
+        # GIVEN the UK country ID
+        country_id = "uk"
+
+        # WHEN we get the metadata
+        metadata = service.get_metadata(country_id)
+
+        # THEN it should have UK-specific data
+        uk_regions = metadata["economy_options"]["region"]
+        expected_regions = ["uk", "eng", "scot", "wales", "ni"]
+        for region in expected_regions:
+            assert any(r["name"] == region for r in uk_regions)
+
+        # Verify UK time periods
+        time_periods = metadata["economy_options"]["time_period"]
+        assert any(period["name"] == 2024 for period in time_periods)
+        assert any(period["name"] == 2025 for period in time_periods)
+
+    def test_get_metadata_verify_us_specific_data(self, service, test_db):
+        # GIVEN the US country ID
+        country_id = "us"
+
+        # WHEN we get the metadata
+        metadata = service.get_metadata(country_id)
+
+        # THEN it should have US-specific data
+        us_regions = metadata["economy_options"]["region"]
+        expected_regions = ["us", "ca", "ny", "tx", "fl"]  # Sample of states
+        for region in expected_regions:
+            assert any(r["name"] == region for r in us_regions)
+
+        # Verify US datasets
+        datasets = metadata["economy_options"]["datasets"]
+        assert any(dataset["name"] == "cps" for dataset in datasets)
+        assert any(dataset["name"] == "enhanced_cps" for dataset in datasets)
+
+        # Verify US time periods
+        time_periods = metadata["economy_options"]["time_period"]
+        assert any(period["name"] == 2023 for period in time_periods)
+        assert any(period["name"] == 2024 for period in time_periods)