fix: add unit tests

scripts/create-package/utils.test.ts

@@ -152,6 +152,92 @@ describe('create-package/utils', () => {
       });
     });
 
+    it('should write the expected files if the directory does not exist', async () => {
+      const packageData: PackageData = {
+        name: '@metamask/foo',
+        description: 'A foo package.',
+        directoryName: 'foo',
+        nodeVersions: '>=18.0.0',
+        currentYear: '2023',
+      };
+
+      const monorepoFileData = {
+        tsConfig: {
+          references: [{ path: './packages/bar' }],
+        },
+        tsConfigBuild: {
+          references: [{ path: './packages/bar' }],
+        },
+        nodeVersions: '>=18.0.0',
+      };
+
+      const mockError = new Error('Not found') as NodeJS.ErrnoException;
+      mockError.code = 'ENOENT';
+
+      (fs.promises.stat as jest.Mock).mockResolvedValueOnce({
+        isDirectory: () => false,
+      });
+
+      (fsUtils.readAllFiles as jest.Mock).mockResolvedValueOnce({
+        'src/index.ts': 'export default 42;',
+        'src/index.test.ts': 'export default 42;',
+        'mock1.file':
+          'CURRENT_YEAR NODE_VERSIONS PACKAGE_NAME PACKAGE_DESCRIPTION PACKAGE_DIRECTORY_NAME',
+        'mock2.file': 'CURRENT_YEAR NODE_VERSIONS PACKAGE_NAME',
+        'mock3.file': 'PACKAGE_DESCRIPTION PACKAGE_DIRECTORY_NAME',
+      });
+
+      (prettier.format as jest.Mock).mockImplementation((input) => input);
+
+      await finalizeAndWriteData(packageData, monorepoFileData);
+
+      // processTemplateFiles and writeFiles
+      expect(fsUtils.readAllFiles).toHaveBeenCalledTimes(1);
+      expect(fsUtils.readAllFiles).toHaveBeenCalledWith(
+        expect.stringMatching(/\/package-template$/u),
+      );
+
+      expect(fsUtils.writeFiles).toHaveBeenCalledTimes(1);
+      expect(fsUtils.writeFiles).toHaveBeenCalledWith(
+        expect.stringMatching(/packages\/foo$/u),
+        {
+          'src/index.ts': 'export default 42;',
+          'src/index.test.ts': 'export default 42;',
+          'mock1.file': '2023 >=18.0.0 @metamask/foo A foo package. foo',
+          'mock2.file': '2023 >=18.0.0 @metamask/foo',
+          'mock3.file': 'A foo package. foo',
+        },
+      );
+
+      // Writing monorepo files
+      expect(fs.promises.writeFile).toHaveBeenCalledTimes(2);
+      expect(prettier.format).toHaveBeenCalledTimes(2);
+      expect(fs.promises.writeFile).toHaveBeenCalledWith(
+        expect.stringMatching(/tsconfig\.json$/u),
+        JSON.stringify({
+          references: [{ path: './packages/bar' }, { path: './packages/foo' }],
+        }),
+      );
+      expect(fs.promises.writeFile).toHaveBeenCalledWith(
+        expect.stringMatching(/tsconfig\.build\.json$/u),
+        JSON.stringify({
+          references: [
+            { path: './packages/bar' },
+            { path: './packages/foo/tsconfig.build.json' },
+          ],
+        }),
+      );
+
+      // Postprocessing
+      expect(execa).toHaveBeenCalledTimes(2);
+      expect(execa).toHaveBeenCalledWith('yarn', ['install'], {
+        cwd: expect.any(String),
+      });
+      expect(execa).toHaveBeenCalledWith('yarn', ['update-readme-content'], {
+        cwd: expect.any(String),
+      });
+    });
+
     it('throws if the package directory already exists', async () => {
       const packageData: PackageData = {
         name: '@metamask/foo',