add testing lib jest dom types, fixes #311

packages/cli/templates/default-plugin/package.json.hbs

@@ -11,7 +11,8 @@
     "test": "backstage-cli test"
   },
   "devDependencies": {
-    "@spotify-backstage/cli": "^{{version}}"
+    "@spotify-backstage/cli": "^{{version}}",
+    "@types/testing-library__jest-dom": "5.0.2"
   },
   "dependencies": {
     "@material-ui/lab": "4.0.0-alpha.45"

packages/cli/templates/default-plugin/src/components/ExampleComponent/ExampleComponent.test.tsx.hbs

@@ -17,10 +17,15 @@
 import React from 'react';
 import { render } from '@testing-library/react';
 import ExampleComponent from './ExampleComponent';
+import { ThemeProvider } from '@material-ui/core';
+import { BackstageTheme } from '@spotify-backstage/core';
 
 describe('ExampleComponent', () => {
   it('should render', () => {
-    const rendered = render(<ExampleComponent />);
+    const rendered = render(
+      <ThemeProvider theme={BackstageTheme}>
+        <ExampleComponent />
+      </ThemeProvider>,);
     expect(rendered.getByText('Welcome to {{ id }}!')).toBeInTheDocument();
   });
 });