test(frontend): add basic Selenium testing

So far, this just checks that the main pages (as listed in the navigation bar) do not 404, have a Django ProgrammingError page displayed, etc. The test uses the Chromium webdriver because it is more complex to set up one test to run with two different webdrivers in sequence. It also opts for emulating the common _desktop_ resolution of 1080p (future tests could check that the navbar expander, etc., work properly, but this is out of scope for test #1).

Dockerfile-dev

@@ -18,7 +18,7 @@ RUN <<EOF
   set -exo pipefail
   apt-get update
   apt-get -y upgrade
-  apt-get install -y --no-install-recommends libmagic1 gettext graphviz graphviz-dev
+  apt-get install -y --no-install-recommends libmagic1 gettext graphviz graphviz-dev chromium
   pip install --upgrade pip
   pip install -r requirements-dev.txt
 EOF

app/general/tests/test_frontend.py

@@ -0,0 +1,64 @@
+from django.contrib.staticfiles.testing import StaticLiveServerTestCase
+from selenium.common import TimeoutException
+from selenium.webdriver.chrome.webdriver import WebDriver, Options
+from selenium.webdriver.common.by import By
+from selenium.webdriver.support.wait import WebDriverWait
+
+
+# Wait timeout in seconds
+WAIT_TIMEOUT = 5
+
+
+class TestFrontend(StaticLiveServerTestCase):
+    @classmethod
+    def setUpClass(cls):
+        opts = Options()
+        opts.add_argument("--headless")
+        opts.add_argument("--no-sandbox")
+        opts.add_argument("--disable-dev-shm-usage")
+        opts.add_argument("--window-size=1920,1080")
+        cls.driver = WebDriver(opts)
+        cls.driver.implicitly_wait(WAIT_TIMEOUT)
+        super().setUpClass()
+
+    @classmethod
+    def tearDownClass(cls):
+        cls.driver.quit()
+        super().tearDownClass()
+
+    def test_no_404s(self):
+        # Sanity check in case we ever change the 404 title
+        self.driver.get(f"{self.live_server_url}/blabla404")
+        print(self.driver.title)
+        assert self.driver.title.startswith(
+            "Error"
+        ), f"Actual title was {self.driver.title}. Page: {self.driver.page_source}"
+
+        # Check main page does not 404
+        self.driver.get(self.live_server_url)
+        self.assert_current_page_not_error()
+
+        # Check all nav items
+        for item in ["Search", "Institutions", "Projects", "Documents", "Languages", "Subjects"]:
+            self.check_nav_item(item)
+
+    def check_nav_item(self, link_text):
+        self.driver.find_element(By.PARTIAL_LINK_TEXT, link_text).click()
+
+        # We use 'in' to do a more permissive match (for instance 'Search' is usually '<search query> - Search'
+        try:
+            wait = WebDriverWait(self.driver, timeout=WAIT_TIMEOUT)
+            wait.until(lambda d: link_text in self.driver.title)
+        except TimeoutException:
+            assert link_text in self.driver.title, (
+                f"Expected title for page {link_text} to have {link_text};"
+                f" was {self.driver.title}"
+            )
+        self.assert_current_page_not_error()
+
+    def assert_current_page_not_error(self):
+        assert not self.driver.title.startswith("Error"), f"Actual title was {self.driver.title}"
+        assert not self.driver.title.startswith(
+            "ProgrammingError"
+        ), f"Actual title was {self.driver.title}"
+        assert not self.driver.find_element(By.ID, "error-block").is_displayed()

requirements-test.txt

@@ -3,3 +3,4 @@ django-debug-toolbar
 django-extensions
 faker
 ruff
+selenium==4.25.0