util methods with unit tests added

unit-test/test_utils.py

+from unittest import TestCase
+import unittest.mock as mock
+from utils import digits_in_string, make_directory, read_json
+import random
+import os.path as osp
+import os
+import json
+
+
+class TestUtils(TestCase):
+    def setUp(self):
+        self.current_dir = os.getcwd()
+
+    def tearDown(self):
+        for dir in os.listdir(self.current_dir):
+            if (osp.isdir(dir)):
+                os.rmdir(dir)
+
+    def test_digits_in_string(self):
+        txt = 'video10'
+        digit = 10
+        self.assertEqual(digits_in_string(txt), int(digit))
+        self.assertEqual(type(digits_in_string(txt)), int)
+
+    def test_make_directory(self):
+        dir = os.path.join(self.current_dir, 'test_dir' + str(random.randint(1, 10000)))
+        print(dir)
+        dir = make_directory(dir)
+        self.assertTrue(osp.exists(dir), False)
+
+    def test_open_json_file(self):
+        # test valid JSON
+        read_data = json.dumps({'a': 1, 'b': 2, 'c': 3})
+        mock_open = mock.mock_open(read_data=read_data)
+        with mock.patch('builtins.open', mock_open):
+            result = read_json('file')
+        self.assertEqual({'a': 1, 'b': 2, 'c': 3}, result)
+        # test invalid JSON
+        read_data = ''
+        mock_open = mock.mock_open(read_data=read_data)
+        with mock.patch("builtins.open", mock_open):
+            with self.assertRaises(ValueError) as context:
+                read_json('file')
+            self.assertEqual(
+                'file is not valid', str(context.exception))
+        # test file does not exist
+        with self.assertRaises(IOError) as context:
+            read_json('null')
+        self.assertEqual(
+            'null does not exist.', str(context.exception))

utils.py

+import re
+import json
+import os
+
+
+def read_json(file_path):
+    try:
+        with open(file_path, 'r') as f:
+            try:
+                return json.load(f)
+            except ValueError:
+                raise ValueError('{} is not valid'.format(file_path))
+    except IOError:
+        raise IOError('{} does not exist.'.format(file_path))
+
+
+def write_json(obj, file_path):
+    make_directory(os.path.dirname(file_path))
+    with open(file_path, 'w') as f:
+        json.dump(obj, f)
+
+
+def digits_in_string(text):
+    non_digit = re.compile("\D")
+    return int(non_digit.sub("", text))
+
+
+def make_directory(directory):
+    if not os.path.exists(directory):
+        try:
+            os.makedirs(directory)
+        except OSError as err:
+            raise
+
+    return directory