test: add regression and browser contracts

tests/test_frontend_contract.py

@@ -0,0 +1,49 @@
+from __future__ import annotations
+
+import re
+import unittest
+from html.parser import HTMLParser
+from pathlib import Path
+
+
+STATIC_DIR = Path(__file__).resolve().parents[1] / "static"
+
+
+class IdCollector(HTMLParser):
+    def __init__(self) -> None:
+        super().__init__()
+        self.ids: list[str] = []
+
+    def handle_starttag(self, tag, attrs):
+        self.ids.extend(value for key, value in attrs if key == "id" and value)
+
+
+class FrontendContractTests(unittest.TestCase):
+    @classmethod
+    def setUpClass(cls) -> None:
+        cls.html = (STATIC_DIR / "index.html").read_text(encoding="utf-8")
+        cls.script = (STATIC_DIR / "app.js").read_text(encoding="utf-8")
+        collector = IdCollector()
+        collector.feed(cls.html)
+        cls.ids = collector.ids
+
+    def test_html_ids_are_unique(self):
+        duplicates = sorted({item for item in self.ids if self.ids.count(item) > 1})
+        self.assertEqual(duplicates, [])
+
+    def test_literal_id_selectors_exist_in_html(self):
+        selectors = set(re.findall(r'querySelector\("#([A-Za-z][A-Za-z0-9_-]*)"\)', self.script))
+        selectors.update(re.findall(r'getElementById\("([A-Za-z][A-Za-z0-9_-]*)"\)', self.script))
+        selectors.update(re.findall(r'setText\("([A-Za-z][A-Za-z0-9_-]*)"', self.script))
+        missing = sorted(selectors - set(self.ids))
+        self.assertEqual(missing, [])
+
+    def test_all_primary_views_have_navigation_entries(self):
+        views = set(re.findall(r'id="([A-Za-z][A-Za-z0-9_-]*View|limitPool)" class="workspace-view', self.html))
+        navigation = set(re.findall(r'data-view="([A-Za-z][A-Za-z0-9_-]*)"', self.html))
+        self.assertEqual(views, navigation)
+        self.assertEqual(len(views), 13)
+
+
+if __name__ == "__main__":
+    unittest.main()