reorganization of tests (1 route per file), add some basic tests

tests/test_api/conftest.py

@@ -0,0 +1,18 @@
+import sys
+import pytest
+
+from app.app import create_app
+from app.main import get_args
+
+
+@pytest.fixture()
+def app():
+    sys.argv = ['']
+    app = create_app(get_args())
+
+    yield app
+
+
+@pytest.fixture()
+def client(app):
+    return app.test_client()