add test for version command

Author: aminzer

src/__tests__/version.test.ts

@@ -0,0 +1,32 @@
+import assert from 'node:assert';
+import { beforeEach, describe, it } from 'node:test';
+import { getPackageVersion } from '../showVersion/index.js';
+import main from '../main.js';
+import TestDifferenceFormatter from './TestDifferenceFormatter.js';
+import TestLogger from './TestLogger.js';
+
+describe('version', () => {
+  const logger = new TestLogger();
+  const differenceFormatter = new TestDifferenceFormatter();
+
+  beforeEach(async () => {
+    logger.reset();
+
+    process.argv = ['node', '.', 'version'];
+
+    await main({ logger, differenceFormatter });
+  });
+
+  it('outputs the current library version', async () => {
+    const logs = logger.getMessages();
+    assert.strictEqual(logs.length, 1);
+
+    const version = logs[0];
+    assert.match(version, /^v\d+\.\d+\.\d+$/);
+    assert.strictEqual(version, `v${getPackageVersion()}`);
+  });
+
+  it("doesn't output any single line messages", async () => {
+    assert.deepStrictEqual(logger.getSingleLineMessages(), []);
+  });
+});

src/showVersion/index.ts

@@ -1 +1,2 @@
+export { default as getPackageVersion } from './getPackageVersion.js';
 export { default } from './showVersion.js';