feat: add migration to add DTL as devDependency

Author: timdeschryver

projects/testing-library/package.json

@@ -26,7 +26,7 @@
     "save": "devDependencies"
   },
   "ng-update": {
-    "migrations": "./schematics/migrations/migration.json"
+    "migrations": "./schematics/migrations/migrations.json"
   },
   "peerDependencies": {
     "@angular/common": ">= 17.0.0",

projects/testing-library/schematics/migrations/dtl-as-peer-dependency/index.spec.ts

@@ -0,0 +1,44 @@
+import { SchematicTestRunner, UnitTestTree } from '@angular-devkit/schematics/testing';
+import * as path from 'path';
+import { EmptyTree } from '@angular-devkit/schematics';
+
+test('adds DTL to peerDependencies', async () => {
+  const tree = await setup({});
+  const pkg = tree.readContent('package.json');
+
+  expect(pkg).toMatchInlineSnapshot(`
+    "{
+      \\"devDependencies\\": {
+        \\"@testing-library/dom\\": \\"^10.0.0\\"
+      }
+    }"
+  `);
+});
+
+test('ignores if DTL is already listed as a dev dependency', async () => {
+  // eslint-disable-next-line @typescript-eslint/naming-convention
+  const tree = await setup({ devDependencies: { '@testing-library/dom': '^9.0.0' } });
+  const pkg = tree.readContent('package.json');
+
+  expect(pkg).toMatchInlineSnapshot(`"{\\"devDependencies\\":{\\"@testing-library/dom\\":\\"^9.0.0\\"}}"`);
+});
+
+test('ignores if DTL is already listed as a dependency', async () => {
+  // eslint-disable-next-line @typescript-eslint/naming-convention
+  const tree = await setup({ dependencies: { '@testing-library/dom': '^11.0.0' } });
+  const pkg = tree.readContent('package.json');
+
+  expect(pkg).toMatchInlineSnapshot(`"{\\"dependencies\\":{\\"@testing-library/dom\\":\\"^11.0.0\\"}}"`);
+});
+
+async function setup(packageJson: object) {
+  const collectionPath = path.join(__dirname, '../migrations.json');
+  const schematicRunner = new SchematicTestRunner('schematics', collectionPath);
+
+  const tree = new UnitTestTree(new EmptyTree());
+  tree.create('package.json', JSON.stringify(packageJson));
+
+  await schematicRunner.runSchematic(`atl-add-dtl-as-peer-dependency`, {}, tree);
+
+  return tree;
+}

projects/testing-library/schematics/migrations/dtl-as-peer-dependency/index.ts

@@ -0,0 +1,20 @@
+import { Rule, SchematicContext, Tree } from '@angular-devkit/schematics';
+import {
+  addPackageJsonDependency,
+  getPackageJsonDependency,
+  NodeDependencyType,
+} from '@schematics/angular/utility/dependencies';
+
+const dtl = '@testing-library/dom';
+
+export default function (): Rule {
+  return async (tree: Tree, context: SchematicContext) => {
+    const dtlDep = getPackageJsonDependency(tree, dtl);
+    if (dtlDep) {
+      context.logger.info(`Skipping installation of '@testing-library/dom' because it's already installed.`);
+    } else {
+      context.logger.info(`Adding '@testing-library/dom' as a peer dependency.`);
+      addPackageJsonDependency(tree, { name: dtl, type: NodeDependencyType.Dev, overwrite: false, version: '^10.0.0' });
+    }
+  };
+}

projects/testing-library/schematics/migrations/migration.json

@@ -0,0 +1,10 @@
+{
+  "$schema": "../../../../node_modules/@angular-devkit/schematics/collection-schema.json",
+  "schematics": {
+    "atl-add-dtl-as-peer-dependency": {
+      "description": "Add @testing-library/dom as a peer dependency",
+      "version": "17.0.0-beta.3",
+      "factory": "./dtl-as-peer-dependency/index"
+    }
+  }
+}

projects/testing-library/schematics/migrations/migrations.json

@@ -1,2 +1,6 @@
 import 'jest-preset-angular/setup-jest';
 import '@testing-library/jest-dom';
+import { TextEncoder, TextDecoder } from 'util';
+
+// eslint-disable-next-line @typescript-eslint/naming-convention
+Object.assign(global, { TextDecoder, TextEncoder });