diff --git a/packages/upload-client/test/sharding.test.js b/packages/upload-client/test/sharding.test.js
index fbd1f1961..1dae6b935 100644
--- a/packages/upload-client/test/sharding.test.js
+++ b/packages/upload-client/test/sharding.test.js
@@ -103,9 +103,23 @@ describe('ShardingStream', () => {
       )
 
     assert.equal(shards.length, 2)
-    assert.ok(shards[0].slices.has(blocks[0].cid.multihash))
-    assert.ok(shards[0].slices.has(blocks[1].cid.multihash))
-    assert.ok(shards[1].slices.has(blocks[2].cid.multihash))
+
+    const shard0Bytes = new Uint8Array(await shards[0].arrayBuffer())
+    const shard1Bytes = new Uint8Array(await shards[1].arrayBuffer())
+
+    // block 0 and 1 should be in shard 0
+    const slice0 = shards[0].slices.get(blocks[0].cid.multihash)
+    assert.ok(slice0)
+    assert(equals(blocks[0].bytes, shard0Bytes.slice(slice0[0], slice0[0] + slice0[1])))
+
+    const slice1 = shards[0].slices.get(blocks[1].cid.multihash)
+    assert.ok(slice1)
+    assert(equals(blocks[1].bytes, shard0Bytes.slice(slice1[0], slice1[0] + slice1[1])))
+
+    // block 2 should be in shard 1
+    const slice2 = shards[1].slices.get(blocks[2].cid.multihash)
+    assert.ok(slice2)
+    assert(equals(blocks[2].bytes, shard1Bytes.slice(slice2[0], slice2[0] + slice2[1])))
   })
 
   it('exceeds shard size when block is encoded with root CID', async () => {