test: add e2e test verifying download integrity via md5 hash

- Add test that verifies downloaded file md5 matches the md5hash
  from the assembly result
- Return assembly status from job promises so tests can access
  result metadata like md5hash

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

Author: kvz

src/cli/assemblies-create.ts

@@ -799,6 +799,7 @@ export default async function run(
               await fsp.unlink(inPath)
             }
           }
+          return assembly
         })()
 
         jobsPromise.add(singleAssemblyPromise)
@@ -877,6 +878,7 @@ export default async function run(
             }
           }
           await completeJob()
+          return assembly
         })()
 
         jobsPromise.add(jobPromise)

test/e2e/cli/assemblies.test.ts

@@ -1,3 +1,4 @@
+import crypto from 'node:crypto'
 import fsp from 'node:fs/promises'
 import process from 'node:process'
 import { promisify } from 'node:util'
@@ -230,6 +231,39 @@ describe('assemblies', () => {
       }),
     )
 
+    it(
+      'should download file with correct md5 hash',
+      testCase(async (client) => {
+        const infile = await imgPromise()
+        const steps = await stepsPromise()
+
+        const output = new OutputCtl()
+        const { results } = await assembliesCreate(output, client, {
+          steps,
+          inputs: [infile],
+          output: 'out-md5.jpg',
+        })
+
+        // Get the assembly result to find the expected md5hash
+        // The results array contains assembly statuses
+        const assemblyResult = results[0] as {
+          results?: Record<string, Array<{ md5hash?: string }>>
+        }
+        expect(assemblyResult).to.have.property('results')
+        const resultSteps = Object.values(assemblyResult.results ?? {})
+        expect(resultSteps.length).to.be.greaterThan(0)
+        const firstResult = resultSteps[0]?.[0]
+        expect(firstResult).to.have.property('md5hash')
+        const expectedMd5 = firstResult?.md5hash
+
+        // Calculate md5 of downloaded file
+        const downloadedBuffer = await fsp.readFile('out-md5.jpg')
+        const actualMd5 = crypto.createHash('md5').update(downloadedBuffer).digest('hex')
+
+        expect(actualMd5).to.equal(expectedMd5)
+      }),
+    )
+
     it(
       'should handle multiple inputs',
       testCase(async (client) => {