add error page test + error on presentation not found

src/components/slides/use-presentation.ts

@@ -25,7 +25,7 @@ export default function usePresentation(): PresentationAndId {
     return onSnapshot(
       doc(firestore, 'presentations', presentationId),
       (snapshot) => {
-        if (!snapshot.exists) {
+        if (!snapshot.exists()) {
           setPageError(
             new Error(`Presentation '${presentationId}' does not exist`),
           );

src/pages/error.e2e.ts

@@ -0,0 +1,33 @@
+import {test, expect} from '../test/coverage-fixture';
+
+test('displays an error when the presentation does not exist', async ({
+  page,
+}) => {
+  const errorLogs: string[] = [];
+  page.on('console', (message) => {
+    if (message.type() === 'error') {
+      errorLogs.push(message.text());
+    }
+  });
+
+  await page.goto(`/v/does-not-exist`);
+
+  await expect(
+    page.getByText('Something is not right. Try refreshing or going home.'),
+  ).toBeVisible();
+
+  await expect(page.getByRole('link', {name: 'refreshing'})).toHaveAttribute(
+    'href',
+    /\/v\/does-not-exist/,
+  );
+
+  await expect(page.getByRole('link', {name: 'home'})).toHaveAttribute(
+    'href',
+    '/',
+  );
+
+  expect(errorLogs.length).toBeGreaterThanOrEqual(1);
+  expect(errorLogs[0]).toMatch(
+    "Error: Presentation 'does-not-exist' does not exist",
+  );
+});