Test for get tracer function with addition functions and fixture

tests/fixtures/tracer_fixtures.py

@@ -0,0 +1,62 @@
+
+import pytest
+import json
+from policyengine_api.services.tracer_analysis_service import TracerAnalysisService
+
+valid_request_body = {
+    "tracer_output": [
+        "only_government_benefit <1500>",
+        "    market_income <1000>",
+        "        employment_income <1000>",
+        "            main_employment_income <1000>",
+        "    non_market_income <500>",
+        "        pension_income <500>",
+    ]
+}
+
+valid_tracer_row = {
+    "household_id": "71424",
+    "policy_id": "2",
+    "country_id": "us",
+    "api_version": "1.150.0",
+    "tracer_output": json.dumps(valid_request_body["tracer_output"]), 
+}
+
+
+@pytest.fixture
+def tracer_service():
+    """Fixture to initialize the TracerAnalysisService."""
+    return TracerAnalysisService()
+
+
+@pytest.fixture
+def test_tracer_data(test_db):
+
+    # Insert data using query()
+    test_db.query(
+        """
+        INSERT INTO tracers (household_id, policy_id, country_id, api_version, tracer_output) 
+        VALUES (?, ?, ?, ?, ?)
+        """,
+        (
+            valid_tracer_row["household_id"],
+            valid_tracer_row["policy_id"],
+            valid_tracer_row["country_id"],
+            valid_tracer_row["api_version"],
+            valid_tracer_row["tracer_output"],
+        ),
+    )
+
+
+    # Verify that the data has been inserted
+    inserted_row = test_db.query(
+        "SELECT * FROM tracers WHERE household_id = ? AND policy_id = ? AND country_id = ? AND api_version = ?",
+        (
+            valid_tracer_row["household_id"],
+            valid_tracer_row["policy_id"],
+            valid_tracer_row["country_id"],
+            valid_tracer_row["api_version"],
+        ),
+    ).fetchone()
+
+    return inserted_row

tests/unit/services/test_tracer_service.py

@@ -0,0 +1,59 @@
+import pytest
+import json
+from policyengine_api.services.tracer_analysis_service import TracerAnalysisService
+from werkzeug.exceptions import NotFound
+
+from tests.fixtures.tracer_fixtures import (
+    test_tracer_data,
+    valid_tracer_row,
+    valid_request_body,
+    tracer_service
+)
+
+
+def test_get_tracer_valid(tracer_service, test_tracer_data):
+    # Test get_tracer successfully retrieves valid data from the database.
+    record = test_tracer_data
+
+    result = tracer_service.get_tracer(
+        record["country_id"], record["household_id"], record["policy_id"], record["api_version"]
+    )
+
+    # match  the valid output as collected from fixture
+    valid_output = valid_request_body["tracer_output"]
+    assert result == valid_output
+
+
+def test_get_tracer_not_found(tracer_service):
+    # Test get_tracer raises NotFound when no matching record exists.
+    with pytest.raises(NotFound):
+        tracer_service.get_tracer("us", "999999", "999", "9.999.0")
+
+
+def test_get_tracer_database_error(tracer_service, test_db):
+    # Test get_tracer handles database errors properly.
+    with pytest.raises(Exception):
+        tracer_service.get_tracer("us", "71424", "2", "1.150.0")
+
+
+def test_invalid_input_type(tracer_service , test_db):
+    # Test get_tracer handles invalid input parameter error
+    with pytest.raises(Exception) as exception_val:
+        tracer_service.get_tracer("us" , 100 , "2" , "1.150.0")
+
+    if exception_val.type == TypeError:
+        assert exception_val.type == TypeError
+    else:
+        pytest.fail(f"Expected value not found instead {type(exception_val)}")
+
+def test_invalid_input_value(tracer_service,test_db):
+    # Test get_tracer handles invalid input value error
+
+    with pytest.raises(Exception) as exception_val:
+        tracer_service.get_tracer("usa" , "-100" , "2" , "1.150.0")
+
+    if exception_val.type == ValueError:
+        assert exception_val.type == ValueError
+    else:
+        pytest.fail(f"Expected value not found instead {type(exception_val)}")
+