Add additional tests

Author: akamat10

tests/lint/unittest_expand_modules.py

@@ -321,3 +321,28 @@ def test_discover_package_path_no_source_root_overlap(tmp_path):
 
     expected = source_roots
     assert package_paths == expected
+
+def test_discover_package_path_legacy():
+    """Test for legacy path discovery when source_roots is empty
+    """
+    source_roots = []
+    package_paths = discover_package_path(__file__, source_roots)
+
+    # First ancestor directory without __init__.py
+    expected = [str(Path(__file__).parent.parent.absolute())]
+
+    assert package_paths == expected
+
+def test_discover_package_path_legacy_no_parent_without_init_py(tmp_path, monkeypatch):
+    """Test to return current directory if no parent directory without
+       __init__.py is found"""
+    source_roots = []
+
+    monkeypatch.setattr(os.path, "exists", lambda path: True)
+    monkeypatch.setattr(os.path, "dirname", lambda path: path)
+
+    package_paths = discover_package_path(tmp_path, source_roots)
+
+    expected = [os.getcwd()]
+
+    assert package_paths == expected