Write tests for templateSelector functions

Signed-off-by: Min Kim <minkimcello@gmail.com>

packages/cli/src/lib/new/templateSelector.test.ts

@@ -0,0 +1,66 @@
+/*
+ * Copyright 2024 The Backstage Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+import { readCliConfig, verifyTemplate } from './templateSelector';
+import { createMockDirectory } from '@backstage/backend-test-utils';
+
+describe('readCliConfig', () => {
+  it('omits default templates if cli defaults are set to false', () => {
+    const { templates } = readCliConfig({ defaults: false });
+    expect(templates).toEqual([]);
+  });
+
+  it('returns default templates if cli config does not exist in pkg json', () => {
+    const { templates } = readCliConfig(undefined);
+    expect(templates.length).toBeGreaterThan(0);
+  });
+
+  it('returns default templates if cli defaults are set to true', () => {
+    const { templates } = readCliConfig({ defaults: true });
+    expect(templates.length).toBeGreaterThan(0);
+  });
+});
+
+describe('verifyTemplate', () => {
+  it('throws an error if template target is a remote URL', () => {
+    expect(() => verifyTemplate({ id: '', target: 'http' })).toThrow(
+      'Remote templates are not supported yet',
+    );
+  });
+
+  it('throws an error if template yaml file does not exist', () => {
+    expect(() => verifyTemplate({ id: '', target: '/foo' })).toThrow(
+      'Your CLI template does not exist: /foo',
+    );
+  });
+
+  it('throws an error if the skeleton of the template does not exist', () => {
+    const mockDir = createMockDirectory({
+      content: { 'template.yaml': 'template: "foo"' },
+    });
+    expect(() =>
+      verifyTemplate({ id: '', target: mockDir.resolve('template.yaml') }),
+    ).toThrow();
+  });
+
+  it('throws an error if template is missing a targetPath', () => {
+    const mockDir = createMockDirectory({
+      content: { 'template.yaml': 'template: "foo"', foo: 'bar' },
+    });
+    expect(() =>
+      verifyTemplate({ id: '', target: mockDir.resolve('template.yaml') }),
+    ).toThrow();
+  });
+});

packages/cli/src/lib/new/templateSelector.ts

@@ -76,6 +76,9 @@ export function verifyTemplate({ id, target }: TemplateLocation): Template {
   if (target.startsWith('http')) {
     throw new Error('Remote templates are not supported yet');
   }
+  if (!fs.existsSync(target)) {
+    throw new Error(`Your CLI template does not exist: ${target}`);
+  }
   const template = parse(fs.readFileSync(target, 'utf-8'));
   const templatePath = paths.resolveTargetRoot(
     dirname(target),