create-app: refactor tests to avoid mock-fs

Signed-off-by: Patrik Oldsberg <poldsberg@gmail.com>

packages/create-app/package.json

@@ -42,6 +42,7 @@
     "recursive-readdir": "^2.2.2"
   },
   "devDependencies": {
+    "@backstage/backend-test-utils": "workspace:^",
     "@backstage/cli": "workspace:^",
     "@types/command-exists": "^1.2.0",
     "@types/fs-extra": "^9.0.1",

packages/create-app/src/createApp.test.ts

@@ -15,13 +15,13 @@
  */
 
 import inquirer from 'inquirer';
-import mockFs from 'mock-fs';
 import path from 'path';
 import { Command } from 'commander';
 import * as tasks from './lib/tasks';
 import createApp from './createApp';
 import { findPaths } from '@backstage/cli-common';
 import { tmpdir } from 'os';
+import { createMockDirectory } from '@backstage/backend-test-utils';
 
 jest.mock('./lib/tasks');
 
@@ -40,16 +40,7 @@ const moveAppMock = jest.spyOn(tasks, 'moveAppTask');
 const buildAppMock = jest.spyOn(tasks, 'buildAppTask');
 
 describe('command entrypoint', () => {
-  beforeEach(() => {
-    mockFs({
-      [`${__dirname}/package.json`]: '', // required by `findPaths(__dirname)`
-      'templates/': mockFs.load(path.resolve(__dirname, '../templates/')),
-    });
-  });
-
-  afterEach(() => {
-    mockFs.restore();
-  });
+  const mockDir = createMockDirectory({ mockOsTmpDir: true });
 
   beforeEach(() => {
     promptMock.mockResolvedValueOnce({
@@ -62,6 +53,7 @@ describe('command entrypoint', () => {
   });
 
   afterEach(() => {
+    mockDir.clear();
     jest.resetAllMocks();
   });
 
@@ -75,7 +67,6 @@ describe('command entrypoint', () => {
       findPaths(__dirname).resolveTarget(
         'packages',
         'create-app',
-        'src',
         'templates',
         'default-app',
       ),
@@ -97,7 +88,6 @@ describe('command entrypoint', () => {
       findPaths(__dirname).resolveTarget(
         'packages',
         'create-app',
-        'src',
         'templates',
         'default-app',
       ),

packages/create-app/src/lib/tasks.test.ts

@@ -15,9 +15,8 @@
  */
 
 import fs from 'fs-extra';
-import mockFs from 'mock-fs';
 import child_process from 'child_process';
-import path, { resolve as resolvePath } from 'path';
+import { resolve as resolvePath } from 'path';
 import os from 'os';
 import {
   Task,
@@ -29,6 +28,7 @@ import {
   tryInitGitRepository,
   readGitConfig,
 } from './tasks';
+import { createMockDirectory } from '@backstage/backend-test-utils';
 
 jest.spyOn(Task, 'log').mockReturnValue(undefined);
 jest.spyOn(Task, 'error').mockReturnValue(undefined);
@@ -101,21 +101,33 @@ describe('tasks', () => {
     ) => void
   >;
 
+  const mockDir = createMockDirectory();
+
+  const realChdir = process.chdir;
+  // If anyone calls chdir then make it resolve within the tmpdir
+  const mockChdir = jest.spyOn(process, 'chdir');
+
   beforeEach(() => {
-    mockFs({
-      'projects/my-module.ts': '',
-      'projects/dir/my-file.txt': '',
-      'tmp/mockApp/.gitignore': '',
-      'tmp/mockApp/package.json': '',
-      'tmp/mockApp/packages/app/package.json': '',
-      // load templates into mock filesystem
-      'templates/': mockFs.load(path.resolve(__dirname, '../../templates/')),
+    mockDir.setContent({
+      projects: {
+        'my-module.ts': '',
+        'dir/my-file.txt': '',
+      },
+      'tmp/mockApp': {
+        '.gitignore': '',
+        'package.json': '',
+        'packages/app/package.json': '',
+      },
     });
+    realChdir(mockDir.path);
+    mockChdir.mockImplementation((dir: string) =>
+      realChdir(mockDir.resolve(dir)),
+    );
   });
 
   afterEach(() => {
     mockExec.mockRestore();
-    mockFs.restore();
+    mockChdir.mockReset();
   });
 
   describe('checkAppExistsTask', () => {
@@ -164,8 +176,6 @@ describe('tasks', () => {
 
   describe('buildAppTask', () => {
     it('should change to `appDir` and run `yarn install` and `yarn tsc`', async () => {
-      const mockChdir = jest.spyOn(process, 'chdir');
-
       // requires callback implementation to support `promisify` wrapper
       // https://stackoverflow.com/a/60579617/10044859
       mockExec.mockImplementation((_command, callback) => {
@@ -199,8 +209,6 @@ describe('tasks', () => {
     });
 
     it('should error out on incorrect yarn version', async () => {
-      const mockChdir = jest.spyOn(process, 'chdir');
-
       // requires callback implementation to support `promisify` wrapper
       // https://stackoverflow.com/a/60579617/10044859
       mockExec.mockImplementation((_command, callback) => {
@@ -265,7 +273,7 @@ describe('tasks', () => {
 
   describe('templatingTask', () => {
     it('should generate a project populating context parameters', async () => {
-      const templateDir = 'templates/default-app';
+      const templateDir = resolvePath(__dirname, '../../templates/default-app');
       const destinationDir = 'templatedApp';
       const context = {
         name: 'SuperCoolBackstageInstance',

yarn.lock

@@ -4206,6 +4206,7 @@ __metadata:
   version: 0.0.0-use.local
   resolution: "@backstage/create-app@workspace:packages/create-app"
   dependencies:
+    "@backstage/backend-test-utils": "workspace:^"
     "@backstage/cli": "workspace:^"
     "@backstage/cli-common": "workspace:^"
     "@types/command-exists": ^1.2.0