Do not install bun on Windows.

package.json

@@ -37,7 +37,7 @@
     "lint:lockfile": "lockfile-lint",
     "lint:markdown": "markdownlint \"**/*.md\" --ignore node_modules --ignore build --config .markdownlint.js",
     "lint:src": "eslint --cache --cache-location node_modules/.cache/.eslintcache --ignore-path .gitignore --report-unused-disable-directives .",
-    "prepare": "husky install",
+    "prepare": "husky install && bash test/bun-setup.sh",
     "prepublishOnly": "npm run build",
     "prettier": "prettier .",
     "test": "mocha test test/package-managers/*",
@@ -116,7 +116,6 @@
     "@types/update-notifier": "^6.0.4",
     "@typescript-eslint/eslint-plugin": "^5.62.0",
     "@typescript-eslint/parser": "^5.62.0",
-    "bun": "^1.0.0",
     "c8": "^7.14.0",
     "chai": "^4.3.7",
     "chai-as-promised": "^7.1.1",

test/bun-setup.sh

@@ -0,0 +1,12 @@
+# Install bun if not installed.
+# Must be run in a prepare script instead of devDependencies to avoid npm install failing on Windows.
+bun -v &> /dev/null
+BUN_EXISTS="$?"
+
+if [ $BUN_EXISTS -ne 0 ]; then
+  npm install -g bun
+fi
+
+# Always return success, even if the install script fails.
+# Windows is expected to fail and the bun tests will be skipped.
+exit 0

test/doctor.test.ts

@@ -54,7 +54,7 @@ const testPass = ({ packageManager }: { packageManager: PackageManagerName }) =>
 
     // touch yarn.lock
     // yarn.lock is necessary otherwise yarn sees the package.json in the npm-check-updates directory and throws an error.
-    if (packageManager === 'yarn') {
+    if (packageManager === 'yarn' || packageManager === 'bun') {
       await fs.writeFile(lockfilePath, '')
     }
 
@@ -84,14 +84,17 @@ const testPass = ({ packageManager }: { packageManager: PackageManagerName }) =>
       rimraf.sync(path.join(cwd, '.pnp.js'))
     }
 
+    // bun prints the run header to stderr instead of stdout
+    if (packageManager === 'bun') {
+      stripAnsi(stderr).should.equal('$ echo Success\n\n$ echo Success\n\n')
+    } else {
+      stderr.should.equal('')
+    }
+
     // stdout should include normal output
-    stderr.should.equal('')
     stripAnsi(stdout).should.containIgnoreCase('Tests pass')
     stripAnsi(stdout).should.containIgnoreCase('ncu-test-v2  ~1.0.0  →  ~2.0.0')
 
-    // stderr should include first failing upgrade
-    stderr.should.equal('')
-
     // package file should include upgrades
     pkgUpgraded.should.containIgnoreCase('"ncu-test-v2": "~2.0.0"')
   })
@@ -459,9 +462,10 @@ else {
     testFail({ packageManager: 'yarn' })
   })
 
-  describe('bun', () => {
-    // TODO: fix doctor bun tests
-    // testPass({ packageManager: 'bun' })
-    // testFail({ packageManager: 'bun' })
+  // Bun not yet supported on Windows
+  const describeSkipWindows = os.platform() === 'win32' ? describe.skip : describe
+  describeSkipWindows('bun', () => {
+    testPass({ packageManager: 'bun' })
+    testFail({ packageManager: 'bun' })
   })
 })

test/package-managers/bun/index.test.ts

@@ -11,16 +11,15 @@ chai.use(chaiString)
 process.env.NCU_TESTS = 'true'
 
 // Bun not yet supported on Windows
-if (os.platform() !== 'win32') {
-  describe('bun', function () {
-    it('list', async () => {
-      const result = await bun.list({ cwd: __dirname })
-      result.should.have.property('ncu-test-v2')
-    })
+const describeSkipWindows = os.platform() === 'win32' ? describe.skip : describe
+describeSkipWindows('bun', function () {
+  it('list', async () => {
+    const result = await bun.list({ cwd: __dirname })
+    result.should.have.property('ncu-test-v2')
+  })
 
-    it('latest', async () => {
-      const { version } = await bun.latest('ncu-test-v2', '1.0.0', { cwd: __dirname })
-      version!.should.equal('2.0.0')
-    })
+  it('latest', async () => {
+    const { version } = await bun.latest('ncu-test-v2', '1.0.0', { cwd: __dirname })
+    version!.should.equal('2.0.0')
   })
-}
+})