Add integration test that repros #821

Reproduces crash in https://github.com/codex-storage/nim-codex/issues/821

tests/integration/testecbug.nim

@@ -0,0 +1,65 @@
+from pkg/libp2p import Cid, init
+import ../examples
+import ./marketplacesuite
+import ./nodeconfigs
+import ./hardhatconfig
+
+marketplacesuite "EC bug":
+
+  test "should be able to create storage request and download dataset",
+    NodeConfigs(
+      # Uncomment to start Hardhat automatically, typically so logs can be
+      # inspected locally
+      hardhat: HardhatConfig().withLogFile().some,
+
+      clients:
+        CodexConfigs.init(nodes=1)
+          # .debug() # uncomment to enable console log output.debug()
+          .withLogFile() # uncomment to output log file to tests/integration/logs/<start_datetime> <suite_name>/<test_name>/<node_role>_<node_idx>.log
+          .withLogTopics("node", "erasure", "marketplace", )
+          .some,
+
+      providers:
+        CodexConfigs.init(nodes=0)
+          # .debug() # uncomment to enable console log output
+          # .withLogFile() # uncomment to output log file to tests/integration/logs/<start_datetime> <suite_name>/<test_name>/<node_role>_<node_idx>.log
+          # .withLogTopics("node", "marketplace", "sales", "reservations", "node", "proving", "clock")
+          .some,
+  ):
+    let reward = 400.u256
+    let duration = 10.periods
+    let collateral = 200.u256
+    let expiry = 5.periods
+    let data = await RandomChunker.example(blocks=8)
+    let client = clients()[0]
+    let clientApi = client.client
+
+    let cid = clientApi.upload(data).get
+
+    var requestId = none RequestId
+    proc onStorageRequested(event: StorageRequested) {.raises:[].} =
+      echo "storage requested event"
+      requestId = event.requestId.some
+
+    let subscription = await marketplace.subscribe(StorageRequested, onStorageRequested)
+
+    # client requests storage but requires multiple slots to host the content
+    let id = await clientApi.requestStorage(
+      cid,
+      duration=duration,
+      reward=reward,
+      expiry=expiry,
+      collateral=collateral,
+      nodes=3,
+      tolerance=1
+    )
+
+    check eventually(requestId.isSome, timeout=expiry.int * 1000)
+
+    let request = await marketplace.getRequest(requestId.get)
+    let cidFromRequest = Cid.init(request.content.cid).get()
+    let downloaded = clientApi.download(cidFromRequest, local = true)
+    check downloaded.isOk
+    check downloaded.get == data
+
+    await subscription.unsubscribe()