scaffolder-backend: refactor template action tests to avoid mock-fs

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

plugins/scaffolder-backend/src/scaffolder/actions/builtin/fetch/template.test.ts

@@ -19,10 +19,8 @@ jest.mock('@backstage/plugin-scaffolder-node', () => {
   return { ...actual, fetchContents: jest.fn() };
 });
 
-import os from 'os';
-import { join as joinPath, sep as pathSep } from 'path';
+import { join as joinPath, resolve as resolvePath, sep as pathSep } from 'path';
 import fs from 'fs-extra';
-import mockFs from 'mock-fs';
 import {
   getVoidLogger,
   resolvePackagePath,
@@ -36,6 +34,7 @@ import {
   ActionContext,
   TemplateAction,
 } from '@backstage/plugin-scaffolder-node';
+import { createMockDirectory } from '@backstage/backend-test-utils';
 
 type FetchTemplateInput = ReturnType<
   typeof createFetchTemplateAction
@@ -43,16 +42,6 @@ type FetchTemplateInput = ReturnType<
   ? U
   : never;
 
-const realFiles = Object.fromEntries(
-  [
-    resolvePackagePath(
-      '@backstage/plugin-scaffolder-backend',
-      'assets',
-      'nunjucks.js.txt',
-    ),
-  ].map(k => [k, mockFs.load(k)]),
-);
-
 const aBinaryFile = fs.readFileSync(
   resolvePackagePath(
     '@backstage/plugin-scaffolder-backend',
@@ -67,14 +56,8 @@ const mockFetchContents = fetchContents as jest.MockedFunction<
 describe('fetch:template', () => {
   let action: TemplateAction<any>;
 
-  const workspacePath = os.tmpdir();
-  const createTemporaryDirectory: jest.MockedFunction<
-    ActionContext<FetchTemplateInput>['createTemporaryDirectory']
-  > = jest.fn(() =>
-    Promise.resolve(
-      joinPath(workspacePath, `${createTemporaryDirectory.mock.calls.length}`),
-    ),
-  );
+  const mockDir = createMockDirectory();
+  const workspacePath = mockDir.resolve('workspace');
 
   const logger = getVoidLogger();
 
@@ -95,24 +78,21 @@ describe('fetch:template', () => {
     logStream: new PassThrough(),
     logger,
     workspacePath,
-    createTemporaryDirectory,
+    async createTemporaryDirectory() {
+      return fs.mkdtemp(mockDir.resolve('tmp-'));
+    },
   });
 
   beforeEach(() => {
-    mockFs({
-      ...realFiles,
+    mockDir.setContent({
+      workspace: {},
     });
-
     action = createFetchTemplateAction({
       reader: Symbol('UrlReader') as unknown as UrlReader,
       integrations: Symbol('Integrations') as unknown as ScmIntegrations,
     });
   });
 
-  afterEach(() => {
-    mockFs.restore();
-  });
-
   it(`returns a TemplateAction with the id 'fetch:template'`, () => {
     expect(action.id).toEqual('fetch:template');
   });
@@ -190,8 +170,7 @@ describe('fetch:template', () => {
         });
 
         mockFetchContents.mockImplementation(({ outputPath }) => {
-          mockFs({
-            ...realFiles,
+          mockDir.setContent({
             [outputPath]: {
               '{% if values.showDummyFile %}dummy-file.txt{% else %}{% endif %}':
                 'dummy file',
@@ -282,13 +261,8 @@ describe('fetch:template', () => {
         });
 
         mockFetchContents.mockImplementation(({ outputPath }) => {
-          mockFs({
-            ...realFiles,
+          mockDir.setContent({
             [outputPath]: {
-              'an-executable.sh': mockFs.file({
-                content: '#!/usr/bin/env bash',
-                mode: parseInt('100755', 8),
-              }),
               'empty-dir-${{ values.count }}': {},
               'static.txt': 'static content',
               '${{ values.name }}.txt': 'static content',
@@ -298,15 +272,27 @@ describe('fetch:template', () => {
               },
               '.${{ values.name }}': '${{ values.itemList | dump }}',
               'a-binary-file.png': aBinaryFile,
-              symlink: mockFs.symlink({
-                path: 'a-binary-file.png',
-              }),
-              brokenSymlink: mockFs.symlink({
-                path: './not-a-real-file.txt',
-              }),
             },
           });
 
+          fs.writeFileSync(
+            resolvePath(outputPath, 'an-executable.sh'),
+            '#!/usr/bin/env bash',
+            {
+              encoding: 'utf-8',
+              mode: parseInt('100755', 8),
+            },
+          );
+
+          fs.symlinkSync(
+            'a-binary-file.png',
+            resolvePath(outputPath, 'symlink'),
+          );
+          fs.symlinkSync(
+            './not-a-real-file.txt',
+            resolvePath(outputPath, 'brokenSymlink'),
+          );
+
           return Promise.resolve();
         });
 
@@ -378,7 +364,11 @@ describe('fetch:template', () => {
 
         await expect(
           fs.realpath(`${workspacePath}/target/symlink`),
-        ).resolves.toBe(joinPath(workspacePath, 'target', 'a-binary-file.png'));
+        ).resolves.toBe(
+          fs.realpathSync(
+            joinPath(workspacePath, 'target', 'a-binary-file.png'),
+          ),
+        );
       });
 
       it('copies broken symlinks as-is without processing them', async () => {
@@ -408,8 +398,7 @@ describe('fetch:template', () => {
       });
 
       mockFetchContents.mockImplementation(({ outputPath }) => {
-        mockFs({
-          ...realFiles,
+        mockDir.setContent({
           [outputPath]: {
             processed: {
               'templated-content-${{ values.name }}.txt': '${{ values.count }}',
@@ -458,8 +447,7 @@ describe('fetch:template', () => {
       });
 
       mockFetchContents.mockImplementation(({ outputPath }) => {
-        mockFs({
-          ...realFiles,
+        mockDir.setContent({
           [outputPath]: {
             processed: {
               'templated-content-${{ values.name }}.txt': '${{ values.count }}',
@@ -509,8 +497,7 @@ describe('fetch:template', () => {
       });
 
       mockFetchContents.mockImplementation(({ outputPath }) => {
-        mockFs({
-          ...realFiles,
+        mockDir.setContent({
           [outputPath]: {
             '{{ cookiecutter.name }}.txt': 'static content',
             subdir: {
@@ -564,8 +551,7 @@ describe('fetch:template', () => {
       });
 
       mockFetchContents.mockImplementation(({ outputPath }) => {
-        mockFs({
-          ...realFiles,
+        mockDir.setContent({
           [outputPath]: {
             'empty-dir-${{ values.count }}': {},
             'static.txt': 'static content',
@@ -646,8 +632,7 @@ describe('fetch:template', () => {
       });
 
       mockFetchContents.mockImplementation(({ outputPath }) => {
-        mockFs({
-          ...realFiles,
+        mockDir.setContent({
           [outputPath]: {
             '${{ values.name }}.njk': '${{ values.name }}: ${{ values.count }}',
             '${{ values.name }}.txt.jinja2':
@@ -687,8 +672,7 @@ describe('fetch:template', () => {
       });
 
       mockFetchContents.mockImplementation(({ outputPath }) => {
-        mockFs({
-          ...realFiles,
+        mockDir.setContent({
           [joinPath(workspacePath, 'target')]: {
             'static-content.txt': 'static-content',
           },
@@ -703,10 +687,6 @@ describe('fetch:template', () => {
       await action.handler(context);
     });
 
-    afterEach(() => {
-      mockFs.restore();
-    });
-
     it('overwrites existing file', async () => {
       await expect(
         fs.readFile(`${workspacePath}/target/static-content.txt`, 'utf-8'),
@@ -728,8 +708,7 @@ describe('fetch:template', () => {
       });
 
       mockFetchContents.mockImplementation(({ outputPath }) => {
-        mockFs({
-          ...realFiles,
+        mockDir.setContent({
           [joinPath(workspacePath, 'target')]: {
             'static-content.txt': 'static-content',
           },