Improve and test html sanitisation

tests/unit_tests/test_ui.py

@@ -0,0 +1,24 @@
+"""Testing the server specified user interface."""
+
+import os
+
+import pytest
+
+from openflexure_microscope_server import ui
+
+from ..shared_utils.md_test_cases import find_test_cases
+
+THIS_DIR = os.path.dirname(os.path.abspath(__file__))
+HTML_SANITISATION_TEST_FILE = os.path.join(
+    THIS_DIR, "data", "html_sanitisation_test_cases.md"
+)
+HTML_SANITISATION_TEST_CASES = find_test_cases(HTML_SANITISATION_TEST_FILE, "html")
+
+
+@pytest.mark.parametrize("test_case", HTML_SANITISATION_TEST_CASES)
+def test_html_block_sanitises(test_case):
+    """Check each case in the test case file sanitises as expected."""
+    sanitised = ui.sanitise_html(test_case.input_code).strip()
+    assert sanitised == test_case.result_code, (
+        f"Test case: '{test_case.title}': Input code doesn't sanitise as expected."
+    )