fix: resolve CI linting and type checking errors

tests/test_extractors.py

@@ -0,0 +1,89 @@
+"""Tests for field extraction module."""
+
+from cmdparse.extractors import extract_array_index, extract_fields, flatten_dict, get_nested_value
+
+
+class TestGetNestedValue:
+    def test_simple_dict_access(self):
+        data = {'name': 'John', 'age': 30}
+        assert get_nested_value(data, 'name') == 'John'
+        assert get_nested_value(data, 'age') == 30
+
+    def test_nested_dict_access(self):
+        data = {'user': {'address': {'city': 'NYC'}}}
+        assert get_nested_value(data, 'user.address.city') == 'NYC'
+
+    def test_list_index_access(self):
+        data = {'items': ['a', 'b', 'c']}
+        assert get_nested_value(data, 'items.0') == 'a'
+        assert get_nested_value(data, 'items.1') == 'b'
+
+    def test_missing_key_returns_none(self):
+        data = {'name': 'John'}
+        assert get_nested_value(data, 'age') is None
+
+    def test_none_data_returns_none(self):
+        assert get_nested_value(None, 'name') is None
+
+
+class TestExtractArrayIndex:
+    def test_with_array_index(self):
+        base, index, rest = extract_array_index('items[0].name')
+        assert base == 'items'
+        assert index == 0
+        assert rest == 'name'
+
+    def test_without_array_index(self):
+        base, index, rest = extract_array_index('name')
+        assert base == 'name'
+        assert index is None
+        assert rest == 'name'
+
+
+class TestExtractFields:
+    def test_extract_single_field(self):
+        data = [{'name': 'John', 'age': 30, 'city': 'NYC'}]
+        result = extract_fields(data, ['name'])
+        assert result == [{'name': 'John'}]
+
+    def test_extract_multiple_fields(self):
+        data = [{'name': 'John', 'age': 30, 'city': 'NYC'}]
+        result = extract_fields(data, ['name', 'city'])
+        assert result == [{'name': 'John', 'city': 'NYC'}]
+
+    def test_extract_nested_fields(self):
+        data = [{'user': {'name': 'John', 'age': 30}}]
+        result = extract_fields(data, ['user.name'])
+        assert result == [{'user.name': 'John'}]
+
+    def test_extract_from_multiple_rows(self):
+        data = [
+            {'name': 'John', 'age': 30},
+            {'name': 'Jane', 'age': 25}
+        ]
+        result = extract_fields(data, ['name'])
+        assert result == [{'name': 'John'}, {'name': 'Jane'}]
+
+    def test_empty_fields_returns_original(self):
+        data = [{'name': 'John', 'age': 30}]
+        result = extract_fields(data, [])
+        assert result == data
+
+    def test_empty_data_returns_empty(self):
+        result = extract_fields([], ['name'])
+        assert result == []
+
+
+class TestFlattenDict:
+    def test_flatten_simple_dict(self):
+        d = {'name': 'John', 'age': 30}
+        result = flatten_dict(d)
+        assert result == {'name': 'John', 'age': 30}
+
+    def test_flatten_nested_dict(self):
+        d = {'user': {'name': 'John', 'address': {'city': 'NYC'}}}
+        result = flatten_dict(d)
+        assert 'user.name' in result
+        assert 'user.address.city' in result
+        assert result['user.name'] == 'John'
+        assert result['user.address.city'] == 'NYC'