fix download

packages/fetch-engine/jest.config.js

@@ -0,0 +1,5 @@
+module.exports = {
+  preset: 'ts-jest',
+  testEnvironment: 'node',
+  modulePathIgnorePatterns: ['build/', 'dist/', 'generator/', 'runtime/', 'scripts/'],
+}

packages/fetch-engine/package.json

@@ -7,17 +7,20 @@
   "author": "Tim Suchanek <suchanek@prisma.io>",
   "devDependencies": {
     "@types/fs-extra": "8.0.1",
+    "@types/jest": "^25.1.2",
     "@types/node": "^12.12.25",
     "@types/node-fetch": "^2.5.4",
     "@types/progress": "^2.0.3",
+    "jest": "^25.1.0",
     "ncc": "^0.3.6",
+    "ts-jest": "^25.2.1",
     "typescript": "^3.7.5"
   },
   "dependencies": {
     "@prisma/get-platform": "workspace:*",
     "chalk": "^3.0.0",
     "debug": "^4.1.1",
-    "execa": "3.4",
+    "execa": "~3.4.0",
     "find-cache-dir": "^3.2.0",
     "htmlparser2": "^4.0.0",
     "http-proxy-agent": "^2.1.0",
@@ -32,7 +35,8 @@
   },
   "scripts": {
     "build": "tsc -d",
-    "prepublishOnly": "pnpm run build"
+    "prepublishOnly": "pnpm run build",
+    "test": "jest"
   },
   "files": [
     "dist"

packages/fetch-engine/src/__tests__/download.test.ts

@@ -0,0 +1,25 @@
+import fs from 'fs'
+import path from 'path'
+import { download, getBinaryName } from '../download'
+import { getPlatform } from '@prisma/get-platform'
+
+describe('download', () => {
+  test('basic download', async () => {
+    const platform = await getPlatform()
+    const targetPath = path.join(__dirname, getBinaryName('query-engine', platform))
+    if (fs.existsSync(targetPath)) {
+      try {
+        fs.unlinkSync(targetPath)
+      } catch (e) {
+        console.error(e)
+      }
+    }
+    await download({
+      binaries: {
+        'query-engine': __dirname,
+      },
+    })
+
+    expect(fs.existsSync(targetPath))
+  })
+})

packages/fetch-engine/src/download.ts

@@ -248,7 +248,7 @@ export async function versionCommandWorks(enginePath: string): Promise<boolean>
   }
 }
 
-function getBinaryName(binaryName: string, platform: string): string {
+export function getBinaryName(binaryName: string, platform: string): string {
   const extension = platform === 'windows' ? '.exe' : ''
   return `${binaryName}-${platform}${extension}`
 }
@@ -271,6 +271,10 @@ async function getCachedBinaryPath({
 
   const cachedTargetPath = path.join(cacheDir, binaryName)
 
+  if (!fs.existsSync(cachedTargetPath)) {
+    return null
+  }
+
   // All versions not called 'latest' are unique
   // only latest needs more checks
   if (version !== 'latest') {