Cover test for each finders and utils

package.json

@@ -89,6 +89,7 @@
     "@types/node": "~16.18.108",
     "@types/pug": "^2.0.10",
     "@types/supertest": "^6.0.2",
+    "@types/which": "^3.0.4",
     "@types/ws": "^8.5.12",
     "@types/yargs": "^17.0.33",
     "@typescript-eslint/eslint-plugin": "^8.5.0",
@@ -149,6 +150,7 @@
     "typed-emitter": "^2.1.0",
     "typescript": "^5.6.2",
     "vhtml": "^2.2.0",
+    "which": "^4.0.0",
     "wrap-ansi": "^9.0.0",
     "yauzl": "^3.1.3",
     "zip-stream": "^6.0.1"

src/browser/finders/chrome.ts

@@ -27,13 +27,10 @@ export const chromeFinder: BrowserFinder = async ({ preferredPath } = {}) => {
         return linux()[0]
       case 'win32':
         return win32()[0]
-      // CI cannot test against WSL environment
-      /* c8 ignore start */
       case 'wsl1':
         return wsl()[0]
     }
     return await fallback()
-    /* c8 ignore stop */
   })()
 
   if (installation) return chrome(installation)

src/browser/finders/edge.ts

@@ -26,13 +26,10 @@ export const edgeFinder: BrowserFinder = async ({ preferredPath } = {}) => {
         return await edgeFinderLinux()
       case 'win32':
         return await edgeFinderWin32()
-      // CI cannot test against WSL environment
-      /* c8 ignore start */
       case 'wsl1':
         return await edgeFinderWSL1()
     }
     return undefined
-    /* c8 ignore stop */
   })()
 
   if (installation) return edge(installation)
@@ -67,15 +64,17 @@ const edgeFinderWin32 = async ({
 } = {}): Promise<string | undefined> => {
   const paths: string[] = []
 
-  for (const prefix of [programFiles, programFilesX86, localAppData]) {
-    if (!prefix) continue
+  const suffixes = [
+    ['Microsoft', 'Edge SxS', 'Application', 'msedge.exe'],
+    ['Microsoft', 'Edge Dev', 'Application', 'msedge.exe'],
+    ['Microsoft', 'Edge Beta', 'Application', 'msedge.exe'],
+    ['Microsoft', 'Edge', 'Application', 'msedge.exe'],
+  ]
 
-    paths.push(
-      path.join(prefix, 'Microsoft', 'Edge SxS', 'Application', 'msedge.exe'),
-      path.join(prefix, 'Microsoft', 'Edge Dev', 'Application', 'msedge.exe'),
-      path.join(prefix, 'Microsoft', 'Edge Beta', 'Application', 'msedge.exe'),
-      path.join(prefix, 'Microsoft', 'Edge', 'Application', 'msedge.exe')
-    )
+  for (const suffix of suffixes) {
+    for (const prefix of [localAppData, programFiles, programFilesX86]) {
+      if (prefix) paths.push(path.join(prefix, ...suffix))
+    }
   }
 
   return await findExecutable(paths)
@@ -87,6 +86,6 @@ const edgeFinderWSL1 = async () => {
   return await edgeFinderWin32({
     programFiles: '/mnt/c/Program Files',
     programFilesX86: '/mnt/c/Program Files (x86)',
-    localAppData: localAppData ? resolveWSLPathToGuestSync(localAppData) : '',
+    localAppData: localAppData && resolveWSLPathToGuestSync(localAppData),
   })
 }

src/browser/finders/firefox.ts

@@ -9,6 +9,11 @@ const firefox = (path: string): BrowserFinderResult => ({
   acceptedBrowsers: [FirefoxBrowser],
 })
 
+const winFirefoxNightly = ['Nightly', 'firefox.exe']
+const winFirefoxNightlyAlt = ['Firefox Nightly', 'firefox.exe']
+const winFirefoxDevEdition = ['Firefox Developer Edition', 'firefox.exe']
+const winFirefoxDefault = ['Mozilla Firefox', 'firefox.exe'] // Firefox stable, ESR, and beta
+
 export const firefoxFinder: BrowserFinder = async ({ preferredPath } = {}) => {
   if (preferredPath) return firefox(preferredPath)
 
@@ -19,11 +24,8 @@ export const firefoxFinder: BrowserFinder = async ({ preferredPath } = {}) => {
         return await firefoxFinderDarwin()
       case 'win32':
         return await firefoxFinderWin32()
-      // CI cannot test against WSL environment
-      /* c8 ignore start */
       case 'wsl1':
         return await firefoxFinderWSL1()
-      /* c8 ignore stop */
     }
     return await firefoxFinderFallback()
   })()
@@ -45,8 +47,8 @@ const firefoxFinderWin32 = async () => {
 
   const winDriveMatcher = /^[a-z]:\\/i
   const winPossibleDrives = () => {
-    const possibleDriveSet = new Set<string>()
-    const pathEnvs = process.env.PATH?.split(';') ?? ['c:\\']
+    const possibleDriveSet = new Set<string>(['c'])
+    const pathEnvs = process.env.PATH?.split(';') ?? []
 
     for (const pathEnv of pathEnvs) {
       if (winDriveMatcher.test(pathEnv)) {
@@ -68,12 +70,14 @@ const firefoxFinderWin32 = async () => {
   }
 
   return await findExecutable(
-    prefixes.flatMap((prefix) => [
-      path.join(prefix, 'Nightly', 'firefox.exe'),
-      path.join(prefix, 'Firefox Nightly', 'firefox.exe'),
-      path.join(prefix, 'Firefox Developer Edition', 'firefox.exe'),
-      path.join(prefix, 'Mozilla Firefox', 'firefox.exe'), // Firefox stable, ESR, and beta
-    ])
+    [
+      winFirefoxNightly,
+      winFirefoxNightlyAlt,
+      winFirefoxDevEdition,
+      winFirefoxDefault,
+    ].flatMap((suffix) =>
+      prefixes.map((prefix) => path.join(prefix, ...suffix))
+    )
   )
 }
 
@@ -82,8 +86,8 @@ const firefoxFinderWSL1 = async () => {
 
   const winDriveMatcher = /^\/mnt\/[a-z]\//i
   const winPossibleDrives = () => {
-    const possibleDriveSet = new Set<string>()
-    const pathEnvs = process.env.PATH?.split(':') ?? ['/mnt/c/']
+    const possibleDriveSet = new Set<string>(['c'])
+    const pathEnvs = process.env.PATH?.split(':') ?? []
 
     for (const pathEnv of pathEnvs) {
       if (winDriveMatcher.test(pathEnv)) {
@@ -100,12 +104,14 @@ const firefoxFinderWSL1 = async () => {
   }
 
   return await findExecutable(
-    prefixes.flatMap((prefix) => [
-      path.join(prefix, 'Nightly', 'firefox.exe'),
-      path.join(prefix, 'Firefox Nightly', 'firefox.exe'),
-      path.join(prefix, 'Firefox Developer Edition', 'firefox.exe'),
-      path.join(prefix, 'Mozilla Firefox', 'firefox.exe'), // Firefox stable, ESR, and beta
-    ])
+    [
+      winFirefoxNightly,
+      winFirefoxNightlyAlt,
+      winFirefoxDevEdition,
+      winFirefoxDefault,
+    ].flatMap((suffix) =>
+      prefixes.map((prefix) => path.join(prefix, ...suffix))
+    )
   )
 }
 

src/browser/finders/utils.ts

@@ -1,13 +1,10 @@
-import { execFile } from 'node:child_process'
 import fs from 'node:fs'
 import path from 'node:path'
-import { promisify } from 'node:util'
 import { parse as parsePlist } from 'fast-plist'
+import nodeWhich from 'which'
 import { debugBrowserFinder } from '../../utils/debug'
 import { isWSL } from '../../utils/wsl'
 
-const execFilePromise = promisify(execFile)
-
 export const getPlatform = async () =>
   (await isWSL()) === 1 ? 'wsl1' : process.platform
 
@@ -28,6 +25,7 @@ const findFirst = async <T>(
   predicate: (path: string) => Promise<T>
 ) => {
   const pathsCount = paths.length
+  if (pathsCount === 0) return undefined
 
   return new Promise<T | undefined>((resolve) => {
     const result = Array<T | undefined>(pathsCount)
@@ -106,22 +104,8 @@ export const findExecutableBinary = async (binaries: string[]) =>
     return undefined
   })
 
-const which = async (command: string) => {
-  if (process.platform === 'win32') {
-    debugBrowserFinder(
-      '"which %s" command is not available on Windows.',
-      command
-    )
-    return undefined
-  }
-
-  try {
-    const { stdout } = await execFilePromise('which', [command])
-    return stdout.split(/\r?\n/)[0]
-  } catch {
-    return undefined
-  }
-}
+export const which = async (command: string) =>
+  (await nodeWhich(command, { nothrow: true })) ?? undefined
 
 // Darwin
 const darwinAppDirectoryMatcher = /.app\/?$/

test/browser/finder.ts

@@ -72,6 +72,64 @@ describe('Browser finder', () => {
       })
     })
 
+    it('resolves a secondary browser if the first finder throws an error', async () => {
+      let $findBrowser!: typeof findBrowser
+      let $ChromeBrowser!: typeof ChromeBrowser
+      let $ChromeCdpBrowser!: typeof ChromeCdpBrowser
+
+      await jest.isolateModulesAsync(async () => {
+        jest
+          .spyOn(
+            await import('../../src/browser/finders/firefox'),
+            'firefoxFinder'
+          )
+          .mockRejectedValue(new Error('Test error'))
+
+        $findBrowser = await import('../../src/browser/finder').then(
+          (m) => m.findBrowser
+        )
+
+        $ChromeBrowser = await import('../../src/browser/browsers/chrome').then(
+          (m) => m.ChromeBrowser
+        )
+
+        $ChromeCdpBrowser = await import(
+          '../../src/browser/browsers/chrome-cdp'
+        ).then((m) => m.ChromeCdpBrowser)
+      })
+
+      const browser = await $findBrowser(['firefox', 'chrome'], {
+        preferredPath: executableMock('empty'),
+      })
+
+      expect(browser).toStrictEqual<typeof browser>({
+        path: expect.stringMatching(/\bempty$/),
+        acceptedBrowsers: [$ChromeBrowser, $ChromeCdpBrowser],
+      })
+    })
+
+    it('rejects when finders are rejected', async () => {
+      let $findBrowser!: typeof findBrowser
+      let $CLIError!: typeof CLIError
+
+      await jest.isolateModulesAsync(async () => {
+        jest
+          .spyOn(
+            await import('../../src/browser/finders/chrome'),
+            'chromeFinder'
+          )
+          .mockRejectedValue(new Error('Test error'))
+
+        $findBrowser = await import('../../src/browser/finder').then(
+          (m) => m.findBrowser
+        )
+
+        $CLIError = await import('../../src/error').then((m) => m.CLIError)
+      })
+
+      await expect($findBrowser(['chrome'])).rejects.toThrow($CLIError)
+    })
+
     describe('with macOS', () => {
       let originalPlatform: string | undefined