cli/new: add config loading tests

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

packages/cli/src/lib/new/preparation/loadConfig.test.ts

@@ -0,0 +1,177 @@
+/*
+ * Copyright 2025 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 { loadConfig } from './loadConfig';
+import { defaultTemplates } from '../defaultTemplates';
+import { createMockDirectory } from '@backstage/backend-test-utils';
+
+describe('loadConfig', () => {
+  const mockPkgJson = {
+    backstage: {
+      new: {
+        templates: [
+          { id: 'template1', target: 'path/to/template1' },
+          { id: 'template2', target: 'path/to/template2' },
+        ],
+        globals: {
+          key1: 'value1',
+          key2: 2,
+          key3: true,
+        },
+      },
+    },
+  };
+
+  const mockDir = createMockDirectory();
+
+  afterEach(() => {
+    mockDir.clear();
+  });
+
+  it('should load configuration from package.json', async () => {
+    mockDir.setContent({
+      'package.json': JSON.stringify({
+        backstage: {
+          new: {
+            templates: [
+              { id: 'template1', target: 'path/to/template1' },
+              { id: 'template2', target: 'path/to/template2' },
+            ],
+            globals: {
+              key1: 'value1',
+              key2: 2,
+              key3: true,
+            },
+          },
+        },
+      }),
+    });
+
+    await expect(
+      loadConfig({
+        packagePath: mockDir.resolve('package.json'),
+      }),
+    ).resolves.toEqual({
+      isUsingDefaultTemplates: false,
+      templatePointers: mockPkgJson.backstage.new.templates,
+      globals: {
+        key1: 'value1',
+        key2: 2,
+        key3: true,
+      },
+    });
+
+    await expect(
+      loadConfig({
+        packagePath: mockDir.resolve('package.json'),
+        globalOverrides: {
+          key2: 'override',
+          key4: 'override2',
+        },
+      }),
+    ).resolves.toEqual({
+      isUsingDefaultTemplates: false,
+      templatePointers: mockPkgJson.backstage.new.templates,
+      globals: {
+        key1: 'value1',
+        key2: 'override',
+        key3: true,
+        key4: 'override2',
+      },
+    });
+  });
+
+  it('should use default templates if none are specified', async () => {
+    mockDir.setContent({
+      'package.json': JSON.stringify({
+        backstage: {
+          new: {
+            globals: {
+              key1: 'value1',
+              key2: 2,
+              key3: true,
+            },
+          },
+        },
+      }),
+    });
+
+    await expect(
+      loadConfig({
+        packagePath: mockDir.resolve('package.json'),
+      }),
+    ).resolves.toEqual({
+      isUsingDefaultTemplates: true,
+      templatePointers: defaultTemplates,
+      globals: {
+        key1: 'value1',
+        key2: 2,
+        key3: true,
+      },
+    });
+  });
+
+  it('should throw an error if package.json is invalid', async () => {
+    mockDir.setContent({
+      'package.json': JSON.stringify({
+        backstage: {
+          new: {
+            templates: 'invalid',
+          },
+        },
+      }),
+    });
+
+    await expect(
+      loadConfig({
+        packagePath: mockDir.resolve('package.json'),
+      }),
+    ).rejects.toThrow(
+      /^Failed to load templating configuration from '.*'; caused by Validation error/,
+    );
+  });
+
+  it('should handle missing backstage.new configuration', async () => {
+    mockDir.setContent({
+      'package.json': JSON.stringify({}),
+    });
+
+    await expect(
+      loadConfig({
+        packagePath: mockDir.resolve('package.json'),
+      }),
+    ).resolves.toEqual({
+      isUsingDefaultTemplates: true,
+      templatePointers: defaultTemplates,
+      globals: {},
+    });
+
+    await expect(
+      loadConfig({
+        packagePath: mockDir.resolve('package.json'),
+        globalOverrides: {
+          key: 'override',
+        },
+      }),
+    ).resolves.toEqual({
+      isUsingDefaultTemplates: true,
+      templatePointers: defaultTemplates,
+      globals: {
+        key: 'override',
+      },
+    });
+  });
+});

packages/cli/src/lib/new/preparation/loadConfig.ts

@@ -48,13 +48,15 @@ const pkgJsonWithNewConfigSchema = z.object({
 });
 
 type LoadConfigOptions = {
-  globalOverrides: Record<string, string | number | boolean>;
+  packagePath?: string;
+  globalOverrides?: Record<string, string | number | boolean>;
 };
 
 export async function loadConfig(
-  options: LoadConfigOptions,
+  options: LoadConfigOptions = {},
 ): Promise<NewConfig> {
-  const pkgPath = paths.resolveTargetRoot('package.json');
+  const pkgPath =
+    options.packagePath ?? paths.resolveTargetRoot('package.json');
   const pkgJson = await fs.readJson(pkgPath);
 
   const parsed = pkgJsonWithNewConfigSchema.safeParse(pkgJson);