3 files changed, 140 insertions, 0 deletions
diff --git a/scripts/tests/get-release-version.test.js b/scripts/tests/get-release-version.test.js
new file mode 100644
index 00000000..3b127644
--- /dev/null
+++ b/scripts/tests/get-release-version.test.js
@@ -0,0 +1,108 @@
+/**
+ * @license
+ * Copyright 2025 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import { vi, describe, it, expect, beforeEach, afterEach } from 'vitest';
+import { getReleaseVersion } from '../get-release-version';
+import { execSync } from 'child_process';
+import * as fs from 'fs';
+
+vi.mock('child_process', () => ({
+  execSync: vi.fn(),
+}));
+
+vi.mock('fs', async (importOriginal) => {
+  const mod = await importOriginal();
+  return {
+    ...mod,
+    readFileSync: vi.fn(),
+  };
+});
+
+describe('getReleaseVersion', () => {
+  const originalEnv = { ...process.env };
+
+  beforeEach(() => {
+    vi.resetModules();
+    process.env = { ...originalEnv };
+    vi.useFakeTimers();
+  });
+
+  afterEach(() => {
+    process.env = originalEnv;
+    vi.clearAllMocks();
+    vi.useRealTimers();
+  });
+
+  it('should calculate nightly version when IS_NIGHTLY is true', () => {
+    process.env.IS_NIGHTLY = 'true';
+    const knownDate = new Date('2025-07-20T10:00:00.000Z');
+    vi.setSystemTime(knownDate);
+    vi.mocked(fs.readFileSync).mockReturnValue(
+      JSON.stringify({ version: '0.1.0' }),
+    );
+    vi.mocked(execSync).mockReturnValue('abcdef');
+    const { releaseTag, releaseVersion, npmTag } = getReleaseVersion();
+    expect(releaseTag).toBe('v0.1.9-nightly.250720.abcdef');
+    expect(releaseVersion).toBe('0.1.9-nightly.250720.abcdef');
+    expect(npmTag).toBe('nightly');
+  });
+
+  it('should use manual version when provided', () => {
+    process.env.MANUAL_VERSION = '1.2.3';
+    const { releaseTag, releaseVersion, npmTag } = getReleaseVersion();
+    expect(releaseTag).toBe('v1.2.3');
+    expect(releaseVersion).toBe('1.2.3');
+    expect(npmTag).toBe('latest');
+  });
+
+  it('should prepend v to manual version if missing', () => {
+    process.env.MANUAL_VERSION = '1.2.3';
+    const { releaseTag } = getReleaseVersion();
+    expect(releaseTag).toBe('v1.2.3');
+  });
+
+  it('should handle pre-release versions correctly', () => {
+    process.env.MANUAL_VERSION = 'v1.2.3-beta.1';
+    const { releaseTag, releaseVersion, npmTag } = getReleaseVersion();
+    expect(releaseTag).toBe('v1.2.3-beta.1');
+    expect(releaseVersion).toBe('1.2.3-beta.1');
+    expect(npmTag).toBe('beta');
+  });
+
+  it('should throw an error for invalid version format', () => {
+    process.env.MANUAL_VERSION = '1.2';
+    expect(() => getReleaseVersion()).toThrow(
+      'Error: Version must be in the format vX.Y.Z or vX.Y.Z-prerelease',
+    );
+  });
+
+  it('should throw an error if no version is provided for non-nightly release', () => {
+    expect(() => getReleaseVersion()).toThrow(
+      'Error: No version specified and this is not a nightly release.',
+    );
+  });
+
+  it('should throw an error for versions with build metadata', () => {
+    process.env.MANUAL_VERSION = 'v1.2.3+build456';
+    expect(() => getReleaseVersion()).toThrow(
+      'Error: Versions with build metadata (+) are not supported for releases.',
+    );
+  });
+});
+
+describe('get-release-version script', () => {
+  it('should print version JSON to stdout when executed directly', () => {
+    const expectedJson = {
+      releaseTag: 'v0.1.0-nightly.20250705',
+      releaseVersion: '0.1.0-nightly.20250705',
+      npmTag: 'nightly',
+    };
+    execSync.mockReturnValue(JSON.stringify(expectedJson));
+
+    const result = execSync('node scripts/get-release-version.js').toString();
+    expect(JSON.parse(result)).toEqual(expectedJson);
+  });
+});
diff --git a/scripts/tests/test-setup.ts b/scripts/tests/test-setup.ts
new file mode 100644
index 00000000..d4c4b465
--- /dev/null
+++ b/scripts/tests/test-setup.ts
@@ -0,0 +1,12 @@
+/**
+ * @license
+ * Copyright 2025 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import { vi } from 'vitest';
+
+vi.mock('fs', () => ({
+  ...vi.importActual('fs'),
+  appendFileSync: vi.fn(),
+}));
diff --git a/scripts/tests/vitest.config.ts b/scripts/tests/vitest.config.ts
new file mode 100644
index 00000000..a8e67005
--- /dev/null
+++ b/scripts/tests/vitest.config.ts
@@ -0,0 +1,20 @@
+/**
+ * @license
+ * Copyright 2025 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import { defineConfig } from 'vitest/config';
+
+export default defineConfig({
+  test: {
+    globals: true,
+    environment: 'node',
+    include: ['scripts/tests/**/*.test.js'],
+    setupFiles: ['scripts/tests/test-setup.ts'],
+    coverage: {
+      provider: 'v8',
+      reporter: ['text', 'lcov'],
+    },
+  },
+});