fix: Zemu.checkAndPullImage should reliably reject

src/emulator.ts

@@ -70,8 +70,8 @@ export default class EmuContainer {
 
   static async checkAndPullImage(imageName: string): Promise<void> {
     const docker = new Docker()
-    await new Promise<void>((resolve) => {
-      docker.pull(imageName, {}, (err: any, stream: any) => {
+    await new Promise<void>((resolve, reject) => {
+      docker.pull(imageName, {}, (err: unknown, stream) => {
         function onProgress(event: any): void {
           const progress = event?.progress ?? ''
           const status = event?.status ?? ''
@@ -81,18 +81,19 @@ export default class EmuContainer {
         function onFinished(err: any, _output: any): void {
           if (err != null) {
             process.stdout.write(`[DOCKER] ${err}\n`)
-            throw err
+            reject(err)
           }
           resolve()
         }
 
         if (err != null) {
           process.stdout.write(`[DOCKER] ${err}\n`)
-          throw err
+          reject(err)
         }
 
-        // eslint-disable-next-line @typescript-eslint/no-unsafe-argument
-        docker.modem.followProgress(stream, onFinished, onProgress)
+        if (stream) {
+          docker.modem.followProgress(stream, onFinished, onProgress)
+        }
       })
     })
   }

tests/check-and-pull-image.test.ts

@@ -0,0 +1,23 @@
+import { describe, expect, test, vi } from 'vitest'
+import EmuContainer from '../src/emulator'
+import Zemu from '../src/Zemu'
+import { DEFAULT_EMU_IMG } from '../src/constants'
+
+describe('checkAndPullImage fails', () => {
+  const BAD_IMAGE_NAME = 'this is not a valid image name'
+
+  test('EmuContainer should throw if checking for image fails', async () => {
+    await expect(() => EmuContainer.checkAndPullImage(BAD_IMAGE_NAME)).rejects.toThrow()
+  })
+
+  test('Zemu should throw if checking for image fails', async () => {
+    vi.spyOn(EmuContainer, 'checkAndPullImage').mockImplementationOnce(async (discarded) => {
+      // expect a typical call
+      expect(discarded).toBe(DEFAULT_EMU_IMG)
+      // forward to the original implementation
+      return EmuContainer.checkAndPullImage(BAD_IMAGE_NAME)
+    })
+
+    await expect(() => Zemu.checkAndPullImage()).rejects.toThrow()
+  })
+})