feat: allow upload without screenshot with externalBuildId

src/upload.js

@@ -74,7 +74,7 @@ async function upload(options) {
 
   const screenshots = await readScreenshots({ cwd: directory, ignore })
 
-  if (screenshots.length === 0) {
+  if (screenshots.length === 0 && !externalBuildId) {
     throw new UploadError(
       `The path provided doesn't contain any image (${GLOB_PATTERN}).`,
     )

src/upload.test.js

@@ -87,6 +87,10 @@ describe('upload', () => {
   })
 
   describe('without screenshots', () => {
+    beforeEach(() => {
+      fetch.mockImplementation(async () => {})
+    })
+
     it('should throw', async () => {
       expect.assertions(1)
 
@@ -101,6 +105,15 @@ describe('upload', () => {
         )
       }
     })
+
+    it('should not throw with externalBuildId', async () => {
+      await upload({
+        directory: path.join(__dirname, '../__fixtures__/screenshots/empty'),
+        token: 'myToken',
+        externalBuildId: 'x',
+      })
+      expect(fetch).toHaveBeenCalled()
+    })
   })
 
   describe('with all good', () => {