add test for load

tests/conftest.py

@@ -0,0 +1,2 @@
+def pytest_configure(config):
+    config.addinivalue_line("markers", "e2e: mark as end-to-end test.")

tests/test_gamestonk_terminal.py

@@ -0,0 +1,21 @@
+from unittest.mock import patch
+
+import pandas as pd
+import pytest
+
+from gamestonk_terminal import load
+
+@pytest.mark.e2e
+def test_load_command():
+
+    test_stock = 'TSLA'
+    test_start = '2020-06-04'
+
+    with patch('sys.stdout.write') as mock_out:
+        result = load(['-t', test_stock, '-s', test_start], '', '', '', '')
+
+    args = mock_out.call_args_list[0][0]
+
+    assert result[0] == test_stock
+    assert test_stock in args[0]
+    assert test_start in args[0]