Add unit tests for helper functions

vizro-core/pyproject.toml

@@ -54,7 +54,7 @@ exclude_lines = [
   "if __name__ == .__main__.:",
   "if TYPE_CHECKING:"
 ]
-fail_under = 89
+fail_under = 90
 show_missing = true
 skip_covered = true
 

vizro-core/tests/unit/vizro/_themes/test_create_chart_template.py

@@ -0,0 +1,59 @@
+import pytest
+from pathlib import Path
+from unittest.mock import mock_open, patch
+
+from vizro._themes.create_chart_templates import _extract_last_two_occurrences, extract_bs_variables_from_css_file
+
+@pytest.fixture
+def css_content():
+    css_content = """
+        :root, [data-bs-theme=light] {
+            --bs-primary: #007bff;
+            --bs-tertiary-color: #adb5bd;
+        }
+        :root, [data-bs-theme=dark] {
+            --bs-primary: #375a7f;
+            --bs-secondary: #6c757d;
+            
+        }
+        [data-bs-theme=light] {
+            --bs-primary: #976fd1;
+            --bs-secondary: #444fff;
+        }
+        """
+
+    return css_content
+
+@pytest.mark.parametrize(
+        "variable, expected",
+        [
+            ("--bs-primary", ("#375a7f", "#976fd1")),
+            ("--bs-secondary", ("#6c757d", "#444fff")),
+            ("--bs-tertiary", (None, None)),
+        ],
+    )
+def test_extract_last_two_occurrences(variable, css_content, expected):
+    result_dark, result_light = _extract_last_two_occurrences(variable, css_content)
+    assert (result_dark, result_light) == expected
+
+
+
+def test_extract_bs_variables_from_css_file(css_content):
+    variables = ["--bs-primary", "--bs-secondary", "--bs-tertiary"]
+    expected_dark = {
+        "BS-PRIMARY": "#375a7f",
+        "BS-SECONDARY": "#6c757d",
+        "BS-TERTIARY": None,
+    }
+    expected_light = {
+        "BS-PRIMARY": "#976fd1",
+        "BS-SECONDARY": "#444fff",
+        "BS-TERTIARY": None,
+    }
+
+    mock_path = Path("/fake/path/to/css/vizro-bootstrap.css")
+    with patch("builtins.open", mock_open(read_data=css_content)):
+        result_dark, result_light = extract_bs_variables_from_css_file(variables, mock_path)
+
+    assert result_dark == expected_dark
+    assert result_light == expected_light