feat: add tests for isWsl (#5251)

* refactor: add docs to isWsl and make easier to test

* feat: add tests for isWsl

* fixup!: refactor isWsl and tests

* Update test/unit/node/util.test.ts

Co-authored-by: Asher <ash@coder.com>

* Update test/unit/node/util.test.ts

Co-authored-by: Asher <ash@coder.com>

Co-authored-by: Asher <ash@coder.com>

src/node/util.ts

@@ -377,11 +377,31 @@ export const getMediaMime = (filePath?: string): string => {
   return (filePath && mimeTypes[path.extname(filePath)]) || "text/plain"
 }
 
-export const isWsl = async (): Promise<boolean> => {
-  return (
-    (process.platform === "linux" && os.release().toLowerCase().indexOf("microsoft") !== -1) ||
-    (await fs.readFile("/proc/version", "utf8")).toLowerCase().indexOf("microsoft") !== -1
-  )
+/**
+ * A helper function that checks if the platform is Windows Subsystem for Linux
+ * (WSL)
+ *
+ * @see https://github.com/sindresorhus/is-wsl/blob/main/index.js
+ * @returns {Boolean} boolean if it is WSL
+ */
+export const isWsl = async (
+  platform: NodeJS.Platform,
+  osRelease: string,
+  procVersionFilePath: string,
+): Promise<boolean> => {
+  if (platform !== "linux") {
+    return false
+  }
+
+  if (osRelease.toLowerCase().includes("microsoft")) {
+    return true
+  }
+
+  try {
+    return (await fs.readFile(procVersionFilePath, "utf8")).toLowerCase().includes("microsoft")
+  } catch (_) {
+    return false
+  }
 }
 
 /**
@@ -398,7 +418,7 @@ export const open = async (address: URL | string): Promise<void> => {
   }
   const args = [] as string[]
   const options = {} as cp.SpawnOptions
-  const platform = (await isWsl()) ? "wsl" : process.platform
+  const platform = (await isWsl(process.platform, os.release(), "/proc/version")) ? "wsl" : process.platform
   let command = platform === "darwin" ? "open" : "xdg-open"
   if (platform === "win32" || platform === "wsl") {
     command = platform === "wsl" ? "cmd.exe" : "cmd"

test/unit/node/util.test.ts

@@ -4,6 +4,7 @@ import * as path from "path"
 import { generateUuid } from "../../../src/common/util"
 import { tmpdir } from "../../../src/node/constants"
 import * as util from "../../../src/node/util"
+import { clean, tmpdir as tempDirHelper } from "../../utils/helpers"
 
 describe("getEnvPaths", () => {
   describe("on darwin", () => {
@@ -482,3 +483,57 @@ describe("humanPath", () => {
     expect(actual).toBe(expected)
   })
 })
+
+describe("isWsl", () => {
+  const testName = "wsl"
+
+  beforeAll(async () => {
+    await clean(testName)
+  })
+
+  describe("on Linux (microsoft)", () => {
+    it("should return true", async () => {
+      const fileName = "proc-version"
+      const osRelease = "5.4.0-1066-gke"
+      const pathToFile = path.join(await tempDirHelper(testName), fileName)
+      await fs.writeFile(
+        pathToFile,
+        "Linux version 3.4.0-Microsoft (Microsoft@Microsoft.com) (gcc version 4.7 (GCC) ) #1 SMP PREEMPT Wed Dec 31 14:42:53 PST 2014",
+      )
+      expect(await util.isWsl("linux", osRelease, pathToFile)).toBe(true)
+    })
+  })
+  describe("on Linux (non-microsoft)", () => {
+    it("should return false", async () => {
+      const fileName = "proc-version2"
+      const osRelease = "Linux"
+      const pathToFile = path.join(await tempDirHelper(testName), fileName)
+      await fs.writeFile(
+        pathToFile,
+        "Linux version 5.4.0-1066-gke (buildd@lcy02-amd64-039) (gcc version 9.4.0 (Ubuntu 9.4.0-1ubuntu1~20.04)) #69-Ubuntu SMP Fri Mar 11 13:52:45 UTC 202",
+      )
+      expect(await util.isWsl("linux", osRelease, pathToFile)).toBe(false)
+    })
+  })
+  describe("on Win32 with microsoft in /proc/version", () => {
+    it("should return false", async () => {
+      const fileName = "proc-version3"
+      const osRelease = "3.4.0-Microsoft"
+      const pathToFile = path.join(await tempDirHelper(testName), fileName)
+      await fs.writeFile(
+        pathToFile,
+        "Linux version 3.4.0-Microsoft (Microsoft@Microsoft.com) (gcc version 4.7 (GCC) ) #1 SMP PREEMPT Wed Dec 31 14:42:53 PST 2014",
+      )
+      expect(await util.isWsl("win32", osRelease, pathToFile)).toBe(false)
+    })
+  })
+  describe("on Darwin", () => {
+    it("should return false", async () => {
+      const fileName = "proc-version4"
+      const osRelease =
+        "Darwin Roadrunner.local 10.3.0 Darwin Kernel Version 10.3.0: Fri Feb 26 11:58:09 PST 2010; root:xnu-1504.3.12~1/RELEASE_I386 i386"
+      const pathToFile = path.join(await tempDirHelper(testName), fileName)
+      expect(await util.isWsl("darwin", osRelease, pathToFile)).toBe(false)
+    })
+  })
+})