Add more comprehensive tests

Author: singiamtel

tests/test_utilities.py

@@ -358,5 +358,26 @@ def test_cycle(self) -> None:
             list(topological_sort(specs))
           self.assertEqual(cm.exception.code, 1)
           mock_error.assert_called_once_with("%s", "Dependency cycle detected: A -> B -> C -> D -> A")
+
+    def test_empty_set(self) -> None:
+        """Test that an empty set of packages is handled correctly."""
+        self.assertEqual([], list(topological_sort({})))
+        
+    def test_single_package(self) -> None:
+        """Test that a single package with no dependencies is handled correctly."""
+        self.assertEqual(["A"], list(topological_sort({
+            "A": {"package": "A", "requires": []}
+        })))
+        
+    def test_independent_packages(self) -> None:
+        """Test that packages with no dependencies between them are handled correctly."""
+        result = list(topological_sort({
+            "A": {"package": "A", "requires": []},
+            "B": {"package": "B", "requires": []},
+            "C": {"package": "C", "requires": []}
+        }))
+        self.assertEqual(set(["A", "B", "C"]), set(result))
+        self.assertEqual(3, len(result))
+
 if __name__ == '__main__':
-    unittest.main()
+    unittest.main()