add test to ensure that dehydrated device gets removed on identity re…

…set (#29354)

playwright/e2e/crypto/dehydration.spec.ts

@@ -116,6 +116,40 @@ test.describe("Dehydration", () => {
         expect(dehydratedDeviceIds.length).toBe(1);
         expect(dehydratedDeviceIds[0]).not.toEqual(initialDehydratedDeviceIds[0]);
     });
+
+    test("'Reset cryptographic identity' removes dehydrated device", async ({ page, homeserver, app, credentials }) => {
+        await logIntoElement(page, credentials);
+
+        // Create a dehydrated device by setting up recovery (see "'Set up
+        // recovery' creates dehydrated device" test above)
+        const settingsDialogLocator = await app.settings.openUserSettings("Encryption");
+        await settingsDialogLocator.getByRole("button", { name: "Set up recovery" }).click();
+
+        // First it displays an informative panel about the recovery key
+        await expect(settingsDialogLocator.getByRole("heading", { name: "Set up recovery" })).toBeVisible();
+        await settingsDialogLocator.getByRole("button", { name: "Continue" }).click();
+
+        // Next, it displays the new recovery key. We click on the copy button.
+        await expect(settingsDialogLocator.getByText("Save your recovery key somewhere safe")).toBeVisible();
+        await settingsDialogLocator.getByRole("button", { name: "Copy" }).click();
+        const recoveryKey = await app.getClipboard();
+        await settingsDialogLocator.getByRole("button", { name: "Continue" }).click();
+
+        await expect(
+            settingsDialogLocator.getByText("Enter your recovery key to confirm", { exact: true }),
+        ).toBeVisible();
+        await settingsDialogLocator.getByRole("textbox").fill(recoveryKey);
+        await settingsDialogLocator.getByRole("button", { name: "Finish set up" }).click();
+
+        await expectDehydratedDeviceEnabled(app);
+
+        // After recovery is set up, we reset our cryptographic identity, which
+        // should drop the dehydrated device.
+        await settingsDialogLocator.getByRole("button", { name: "Reset cryptographic identity" }).click();
+        await settingsDialogLocator.getByRole("button", { name: "Continue" }).click();
+
+        await expectDehydratedDeviceDisabled(app);
+    });
 });
 
 async function getDehydratedDeviceIds(client: Client): Promise<string[]> {
@@ -144,3 +178,16 @@ async function expectDehydratedDeviceEnabled(app: ElementAppPage): Promise<void>
         })
         .toEqual(1);
 }
+
+/** Wait for our user to not have a dehydrated device */
+async function expectDehydratedDeviceDisabled(app: ElementAppPage): Promise<void> {
+    // It might be nice to do this via the UI, but currently this info is not exposed via the UI.
+    //
+    // Note we might have to wait for the device list to be refreshed, so we wrap in `expect.poll`.
+    await expect
+        .poll(async () => {
+            const dehydratedDeviceIds = await getDehydratedDeviceIds(app.client);
+            return dehydratedDeviceIds.length;
+        })
+        .toEqual(0);
+}