Added simple testcase.

tests/test_usage.py

@@ -0,0 +1,58 @@
+# -*- coding: utf-8 -*-
+from __future__ import (
+    division, absolute_import, print_function, unicode_literals,
+)
+from builtins import *                  # noqa
+from future.builtins.disabled import *  # noqa
+
+from tempfile import NamedTemporaryFile
+import random
+import string
+
+import pytest
+
+from img2url.config import load_and_check_config
+from img2url.github import load_file, create_file, update_file
+
+
+def random_str(n):
+    return ''.join(
+        random.SystemRandom().choice(string.ascii_uppercase)
+        for _ in range(n)
+    )
+
+
+def tmpfile(content, _disable_gc=[]):
+    f = NamedTemporaryFile()
+    _disable_gc.append(f)
+    with open(f.name, 'w', encoding='utf-8') as _f:
+        _f.write(content)
+    return f.name
+
+
+CONFIG_PATH = tmpfile('''
+token: c57e63c26ca29d20352e70f7d6ccc0f039fc7727
+user: img2url-testing
+repo: img2url-testing-travisci
+''')
+
+
+def test_config():
+    load_and_check_config(CONFIG_PATH)
+
+    bad_path = tmpfile('''
+user: img2url-testing
+repo: img2url-testing-travisci
+''')
+    with pytest.raises(RuntimeError):
+        load_and_check_config(bad_path)
+
+
+def test_create_and_update():
+    config = load_and_check_config(CONFIG_PATH)
+
+    path = tmpfile(random_str(10))
+    assert create_file(path, config).status_code == 201
+
+    _, _, sha = load_file(path)
+    assert update_file(path, config, pre_sha=sha).status_code == 200