frontend-plugin-api: add test for createSignInPageExtension

Co-authored-by: Camila Belo <camilaibs@gmail.com>
Co-authored-by: Vincenzo Scamporlino <vincenzos@spotify.com>
Co-authored-by: Philipp Hugenroth <philipph@spotify.com>
Signed-off-by: Patrik Oldsberg <poldsberg@gmail.com>

packages/frontend-plugin-api/src/extensions/createSignInPageExtension.test.tsx

@@ -0,0 +1,47 @@
+/*
+ * Copyright 2023 The Backstage Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import React from 'react';
+import { createExtensionTester } from '@backstage/frontend-test-utils';
+import { screen } from '@testing-library/react';
+import { createSignInPageExtension } from './createSignInPageExtension';
+import { coreExtensionData, createExtension } from '../wiring';
+
+describe('createSignInPageExtension', () => {
+  it('renders a sign-in page', async () => {
+    const SignInPage = createSignInPageExtension({
+      id: 'test',
+      loader: async () => () => <div data-testid="sign-in-page" />,
+    });
+
+    createExtensionTester(
+      createExtension({
+        id: 'dummy',
+        attachTo: { id: 'ignored', input: 'ignored' },
+        output: {
+          element: coreExtensionData.reactElement,
+        },
+        factory: () => ({ element: <div /> }),
+      }),
+    )
+      .add(SignInPage)
+      .render();
+
+    await expect(
+      screen.findByTestId('sign-in-page'),
+    ).resolves.toBeInTheDocument();
+  });
+});