test: test the retrievability of data uploaded with stamper (#1086)

* test: test the retrievability of data uploaded with stamper

* test: update test coverage

* test: undo

* test: update test coverage

---------

Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>

Author: Cafe137

test/integration/stamper.spec.ts

@@ -1,8 +1,8 @@
-import { Types } from 'cafe-utility'
+import { Strings, Types } from 'cafe-utility'
 import { Bytes, MerkleTree, Stamper } from '../../src'
 import { makeBee } from '../utils'
 
-test('Stamper', async () => {
+test('Stamper utilization state', async () => {
   const bee = makeBee()
 
   const stamper = Stamper.fromBlank(
@@ -11,7 +11,9 @@ test('Stamper', async () => {
     17,
   )
 
-  const payload = Bytes.fromUtf8('Hello, client side stamper!')
+  const payload = Bytes.fromUtf8(
+    `Hello, client side stamper! This is a unique test payload: ${Strings.randomAlphanumeric(32)}`,
+  )
 
   const tree = new MerkleTree(async chunk => {
     await bee.uploadChunk(stamper.stamp(chunk), chunk.build())
@@ -33,4 +35,7 @@ test('Stamper', async () => {
 
   nextStamper.stamp(rootChunk)
   expect(() => nextStamper.stamp(rootChunk)).toThrow('Bucket is full')
+
+  const data = await bee.downloadData(rootChunk.hash())
+  expect(data.toUtf8()).toEqual(payload.toUtf8())
 })