Fix salary tool edge cases (#75)

* fix: handle salary tool edge cases

* fix: preserve Danish salary compounds

tests/test_salary_lookup.py

@@ -0,0 +1,41 @@
+import unittest
+
+from salary_lookup import format_entry
+
+
+class FormatEntryTests(unittest.TestCase):
+    def test_zero_count_is_displayed_as_zero(self):
+        entry = {
+            "company": "Example Corp",
+            "city": "",
+            "categories": {
+                "public_data": {
+                    "count": 0,
+                    "index": 100.0,
+                },
+            },
+        }
+
+        rendered = format_entry(entry, {"index_baseline": 100, "index_label": "Index"})
+
+        self.assertRegex(rendered, r"Public Data\s+0\s+100\.0")
+
+    def test_text_index_does_not_crash(self):
+        entry = {
+            "company": "Example Corp",
+            "city": "",
+            "categories": {
+                "sample": {
+                    "count": 3,
+                    "index": "private",
+                },
+            },
+        }
+
+        rendered = format_entry(entry, {"index_baseline": 100, "index_label": "Index"})
+
+        self.assertIn("private", rendered)
+
+
+if __name__ == "__main__":
+    unittest.main()