feat(cli): implement compare command

packages/cli/src/lib/commands.ts

@@ -1,6 +1,7 @@
 import { CommandModule } from 'yargs';
 import { yargsAutorunCommandObject } from './autorun/autorun-command';
 import { yargsCollectCommandObject } from './collect/collect-command';
+import { yargsCompareCommandObject } from './compare/compare-command';
 import { yargsConfigCommandObject } from './print-config/print-config-command';
 import { yargsUploadCommandObject } from './upload/upload-command';
 
@@ -12,5 +13,6 @@ export const commands: CommandModule[] = [
   yargsAutorunCommandObject(),
   yargsCollectCommandObject(),
   yargsUploadCommandObject(),
+  yargsCompareCommandObject(),
   yargsConfigCommandObject(),
 ];

packages/cli/src/lib/compare/compare-command.ts

@@ -0,0 +1,36 @@
+import chalk from 'chalk';
+import { join } from 'node:path';
+import { CommandModule } from 'yargs';
+import { compareReportFiles } from '@code-pushup/core';
+import { PersistConfig } from '@code-pushup/models';
+import { CLI_NAME } from '../constants';
+import type { CompareOptions } from '../implementation/compare.model';
+import { yargsCompareOptionsDefinition } from '../implementation/compare.options';
+import { ui } from '../implementation/logging';
+
+export function yargsCompareCommandObject() {
+  const command = 'compare';
+  return {
+    command,
+    describe: 'Compare 2 report files and create a diff file',
+    builder: yargsCompareOptionsDefinition(),
+    handler: async (args: unknown) => {
+      ui().logger.log(chalk.bold(CLI_NAME));
+      ui().logger.info(chalk.gray(`Run ${command}...`));
+
+      const options = args as CompareOptions & {
+        persist: Required<PersistConfig>;
+      };
+
+      const { before, after, persist } = options;
+      const outputPath = join(
+        persist.outputDir,
+        `${persist.filename}-diff.json`,
+      );
+
+      await compareReportFiles({ before, after }, outputPath);
+
+      ui().logger.info(`Reports diff written to ${chalk.bold(outputPath)}`);
+    },
+  } satisfies CommandModule;
+}

packages/cli/src/lib/compare/compare-command.unit.test.ts

@@ -0,0 +1,33 @@
+import { join } from 'node:path';
+import { compareReportFiles } from '@code-pushup/core';
+import { PERSIST_FILENAME, PERSIST_OUTPUT_DIR } from '@code-pushup/models';
+import { DEFAULT_CLI_CONFIGURATION } from '../../../mocks/constants';
+import { yargsCli } from '../yargs-cli';
+import { yargsCompareCommandObject } from './compare-command';
+
+vi.mock('@code-pushup/core', async () => {
+  const core: object = await vi.importActual('@code-pushup/core');
+  const { CORE_CONFIG_MOCK }: typeof import('@code-pushup/test-utils') =
+    await vi.importActual('@code-pushup/test-utils');
+  return {
+    ...core,
+    autoloadRc: vi.fn().mockResolvedValue(CORE_CONFIG_MOCK),
+    compareReportFiles: vi.fn(),
+  };
+});
+
+describe('compare-command', () => {
+  it('should parse input paths from command line and output path from persist config', async () => {
+    await yargsCli(
+      ['compare', '--before=source-report.json', '--after=target-report.json'],
+      { ...DEFAULT_CLI_CONFIGURATION, commands: [yargsCompareCommandObject()] },
+    ).parseAsync();
+
+    expect(compareReportFiles).toHaveBeenCalledWith<
+      Parameters<typeof compareReportFiles>
+    >(
+      { before: 'source-report.json', after: 'target-report.json' },
+      join(PERSIST_OUTPUT_DIR, `${PERSIST_FILENAME}-diff.json`),
+    );
+  });
+});

packages/cli/src/lib/implementation/compare.model.ts

@@ -0,0 +1,3 @@
+import { Diff } from '@code-pushup/utils';
+
+export type CompareOptions = Diff<string>;

packages/cli/src/lib/implementation/compare.options.ts

@@ -0,0 +1,20 @@
+import { Options } from 'yargs';
+import type { CompareOptions } from './compare.model';
+
+export function yargsCompareOptionsDefinition(): Record<
+  keyof CompareOptions,
+  Options
+> {
+  return {
+    before: {
+      describe: 'Path to source report.json',
+      type: 'string',
+      demandOption: true,
+    },
+    after: {
+      describe: 'Path to target report.json',
+      type: 'string',
+      demandOption: true,
+    },
+  };
+}

packages/cli/src/lib/yargs-cli.integration.test.ts

@@ -1,5 +1,7 @@
 import { describe, expect, it } from 'vitest';
 import { CoreConfig, Format } from '@code-pushup/models';
+import { CompareOptions } from './implementation/compare.model';
+import { yargsCompareOptionsDefinition } from './implementation/compare.options';
 import {
   PersistConfigCliOptions,
   UploadConfigCliOptions,
@@ -118,4 +120,24 @@ describe('yargsCli', () => {
       }),
     );
   });
+
+  it('should parse compare options', async () => {
+    const parsedArgv = await yargsCli<GeneralCliOptions & CompareOptions>(
+      ['--before=source-report.json', '--after', 'target-report.json'],
+      {
+        options: { ...options, ...yargsCompareOptionsDefinition() },
+      },
+    ).parseAsync();
+    expect(parsedArgv.before).toBe('source-report.json');
+    expect(parsedArgv.after).toBe('target-report.json');
+  });
+
+  it('should error if required compare option is missing', () => {
+    expect(() =>
+      yargsCli<GeneralCliOptions & CompareOptions>([], {
+        options: { ...options, ...yargsCompareOptionsDefinition() },
+        noExitProcess: true,
+      }).parse(),
+    ).toThrow('Missing required arguments: before, after');
+  });
 });