fix(salary): validate salary data shape before lookup (#141)

tests/test_salary_lookup.py

@@ -1,7 +1,12 @@
 """Tests for salary_lookup.py — format_entry, match_score, and search_company."""
 
+import io
+import tempfile
 import unittest
+from contextlib import redirect_stderr
+from pathlib import Path
 
+import salary_lookup
 from salary_lookup import (
     format_entry,
     normalize,
@@ -9,6 +14,7 @@ from salary_lookup import (
     extract_core_words,
     match_score,
     search_company,
+    validate_data,
 )
 
 
@@ -165,6 +171,76 @@ class SearchCompanyTests(unittest.TestCase):
         self.assertEqual(results, [])
 
 
+class ValidateDataTests(unittest.TestCase):
+    def assert_invalid_data(self, data, expected_message):
+        stderr = io.StringIO()
+        with self.assertRaises(SystemExit) as raised:
+            with redirect_stderr(stderr):
+                validate_data(data)
+
+        self.assertEqual(raised.exception.code, 1)
+        self.assertIn("Error: invalid salary_data.json", stderr.getvalue())
+        self.assertIn(expected_message, stderr.getvalue())
+        self.assertIn("tools/README_SALARY_TOOL.md", stderr.getvalue())
+
+    def test_valid_minimal_data_is_returned(self):
+        data = {"metadata": {}, "companies": [{"company": "Example Corp"}]}
+
+        self.assertIs(validate_data(data), data)
+
+    def test_top_level_value_must_be_object(self):
+        self.assert_invalid_data([], "top-level JSON value must be an object")
+
+    def test_companies_must_be_list(self):
+        self.assert_invalid_data({"companies": {"company": "Example Corp"}}, "'companies' must be a list")
+
+    def test_metadata_must_be_object_when_provided(self):
+        self.assert_invalid_data(
+            {"metadata": [], "companies": [{"company": "Example Corp"}]},
+            "'metadata' must be an object when provided",
+        )
+
+    def test_load_data_reports_json_parse_errors_without_traceback(self):
+        with tempfile.TemporaryDirectory() as tmpdir:
+            data_file = Path(tmpdir) / "salary_data.json"
+            data_file.write_text('{"companies": [', encoding="utf-8")
+
+            original_data_file = salary_lookup.DATA_FILE
+            salary_lookup.DATA_FILE = data_file
+            try:
+                stderr = io.StringIO()
+                with self.assertRaises(SystemExit) as raised:
+                    with redirect_stderr(stderr):
+                        salary_lookup.load_data()
+            finally:
+                salary_lookup.DATA_FILE = original_data_file
+
+        self.assertEqual(raised.exception.code, 1)
+        self.assertIn("invalid JSON at line", stderr.getvalue())
+        self.assertIn("tools/README_SALARY_TOOL.md", stderr.getvalue())
+
+    def test_company_entry_must_be_object(self):
+        self.assert_invalid_data({"companies": ["Example Corp"]}, "companies[1] must be an object")
+
+    def test_company_name_is_required(self):
+        self.assert_invalid_data({"companies": [{"city": "Aarhus"}]}, "companies[1].company must be a non-empty string")
+
+    def test_company_name_must_not_be_blank(self):
+        self.assert_invalid_data({"companies": [{"company": "  "}]}, "companies[1].company must be a non-empty string")
+
+    def test_city_must_be_string_when_provided(self):
+        self.assert_invalid_data(
+            {"companies": [{"company": "Example Corp", "city": 123}]},
+            "companies[1].city must be a string when provided",
+        )
+
+    def test_categories_must_be_object_when_provided(self):
+        self.assert_invalid_data(
+            {"companies": [{"company": "Example Corp", "categories": []}]},
+            "companies[1].categories must be an object when provided",
+        )
+
+
 class UtilityTests(unittest.TestCase):
     def test_normalize_strips_suffix_and_noise(self):
         self.assertEqual(normalize("Novo Nordisk A/S"), "novonordisk")