test(data_handling.request): add test support

Adds test coverage for code introduced by
9324872.

See: #2

tests/data_handling/test_request.py

@@ -0,0 +1,25 @@
+# -*- coding: utf-8 -*-
+"""Tests for the scripts.data_handling.request submodule.
+
+These unit tests are designed to test that genes are passed to the query correctly.
+They do not test the API,
+as tests of data returned by realworld API queries are best left to integrations tests.
+"""
+
+import pandas as pd
+
+from scripts.data_handling.request import lut_check
+
+lut = pd.DataFrame.from_dict({"name": ["abc", "def"], "id": ["a1", "a2"]})
+
+
+def test_return_none() -> None:
+    """It returns None when the gene is not found."""
+    result = lut_check("ghi", lut)
+    assert result is None
+
+
+def test_return_str() -> None:
+    """It returns the id when the gene is found."""
+    result = lut_check("abc", lut)
+    assert result == "a1"