add test_gendiff.py

Author: annetmyshkina

tests/test_gendiff.py

@@ -0,0 +1,39 @@
+import json
+from pathlib import Path
+from gendiff.find_diff import generate_diff
+
+
+def read_file(filepath):
+    return Path(filepath).read_text()
+
+
+def test_json_diff():
+    data1_path = 'tests/test_data/data1.json'
+    data2_path = 'tests/test_data/data2.json'
+    expected_path = 'tests/test_data/result.txt'
+
+    data1 = json.loads(read_file(data1_path))
+    data2 = json.loads(read_file(data2_path))
+    expected = read_file(expected_path).strip()
+
+    result = generate_diff(data1, data2).strip()
+
+    assert result == expected
+
+def test_key_only_in_first():
+    data1 = {'key1': 'value1'}
+    data2 = {}
+    expected = "{\n  - key1: value1\n}"
+    assert generate_diff(data1, data2) == expected
+
+def test_key_only_in_second():
+    data1 = {}
+    data2 = {'key1': 'value1'}
+    expected = "{\n  + key1: value1\n}"
+    assert generate_diff(data1, data2) == expected
+
+def test_identical_keys():
+    data1 = {'key1': 'value1'}
+    data2 = {'key1': 'value1'}
+    expected = "{\n    key1: value1\n}"
+    assert generate_diff(data1, data2) == expected