diff --git a/codex/blockexchange/engine/discovery.nim b/codex/blockexchange/engine/discovery.nim
index dacfb213..ecfaf3a4 100644
--- a/codex/blockexchange/engine/discovery.nim
+++ b/codex/blockexchange/engine/discovery.nim
@@ -83,7 +83,7 @@ proc advertiseQueueLoop*(b: DiscoveryEngine) {.async.} =
       trace "Exception listing blocks", exc = exc.msg
 
   while b.discEngineRunning:
-    await b.localStore.listBlocks(onBlock)
+    discard await b.localStore.listBlocks(onBlock)
 
     trace "About to sleep advertise loop", sleep = b.advertiseLoopSleep
     await sleepAsync(b.advertiseLoopSleep)
diff --git a/codex/blockexchange/engine/engine.nim b/codex/blockexchange/engine/engine.nim
index 69fda741..964b38eb 100644
--- a/codex/blockexchange/engine/engine.nim
+++ b/codex/blockexchange/engine/engine.nim
@@ -9,6 +9,8 @@
 
 import std/sequtils
 import std/sets
+import std/options
+import std/algorithm
 
 import pkg/chronos
 import pkg/chronicles
@@ -200,7 +202,7 @@ proc blockPresenceHandler*(
     .filter do(cid: Cid) -> bool:
       not b.peers.anyIt( cid in it.peerHave ))
 
-proc scheduleTasks(b: BlockExcEngine, blocks: seq[bt.Block]) =
+proc scheduleTasks(b: BlockExcEngine, blocks: seq[bt.Block]) {.async.} =
   trace "Schedule a task for new blocks"
 
   let
@@ -209,17 +211,18 @@ proc scheduleTasks(b: BlockExcEngine, blocks: seq[bt.Block]) =
   # schedule any new peers to provide blocks to
   for p in b.peers:
     for c in cids: # for each cid
-      # schedule a peer if it wants at least one
-      # cid and we have it in our local store
-      if c in p.peerWants and c in b.localStore:
-        if b.scheduleTask(p):
-          trace "Task scheduled for peer", peer = p.id
-        else:
-          trace "Unable to schedule task for peer", peer = p.id
+      # schedule a peer if it wants at least one cid
+      # and we have it in our local store
+      if c in p.peerWants:
+        if await (c in b.localStore):
+          if b.scheduleTask(p):
+            trace "Task scheduled for peer", peer = p.id
+          else:
+            trace "Unable to schedule task for peer", peer = p.id
 
-        break # do next peer
+          break # do next peer
 
-proc resolveBlocks*(b: BlockExcEngine, blocks: seq[bt.Block]) =
+proc resolveBlocks*(b: BlockExcEngine, blocks: seq[bt.Block]) {.async.} =
   ## Resolve pending blocks from the pending blocks manager
   ## and schedule any new task to be ran
   ##
@@ -227,7 +230,7 @@ proc resolveBlocks*(b: BlockExcEngine, blocks: seq[bt.Block]) =
   trace "Resolving blocks", blocks = blocks.len
 
   b.pendingBlocks.resolve(blocks)
-  b.scheduleTasks(blocks)
+  await b.scheduleTasks(blocks)
   b.discovery.queueProvideBlocksReq(blocks.mapIt( it.cid ))
 
 proc payForBlocks(engine: BlockExcEngine,
@@ -250,11 +253,10 @@ proc blocksHandler*(
 
   trace "Got blocks from peer", peer, len = blocks.len
   for blk in blocks:
-    if not (await b.localStore.putBlock(blk)):
+    if isErr (await b.localStore.putBlock(blk)):
       trace "Unable to store block", cid = blk.cid
-      continue
 
-  b.resolveBlocks(blocks)
+  await b.resolveBlocks(blocks)
   let peerCtx = b.peers.get(peer)
   if peerCtx != nil:
     b.payForBlocks(peerCtx, blocks)
@@ -289,8 +291,9 @@ proc wantListHandler*(
 
     # peer might want to ask for the same cid with
     # different want params
-    if e.sendDontHave and e.cid notin b.localStore:
-      dontHaves.add(e.cid)
+    if e.sendDontHave:
+      if not(await e.cid in b.localStore):
+        dontHaves.add(e.cid)
 
   # send don't have's to remote
   if dontHaves.len > 0:
@@ -358,22 +361,25 @@ proc dropPeer*(b: BlockExcEngine, peer: PeerID) =
 proc taskHandler*(b: BlockExcEngine, task: BlockExcPeerCtx) {.gcsafe, async.} =
   trace "Handling task for peer", peer = task.id
 
-  var wantsBlocks = newAsyncHeapQueue[Entry](queueType = QueueType.Max)
-  # get blocks and wants to send to the remote
-  for e in task.peerWants:
-    if e.wantType == WantType.wantBlock:
-      await wantsBlocks.push(e)
+  # PART 1: Send to the peer blocks he wants to get,
+  # if they present in our local store
 
   # TODO: There should be all sorts of accounting of
   # bytes sent/received here
+
+  var wantsBlocks = task.peerWants.filterIt(it.wantType == WantType.wantBlock)
+
   if wantsBlocks.len > 0:
+    wantsBlocks.sort(SortOrder.Descending)
+
     let blockFuts = await allFinished(wantsBlocks.mapIt(
         b.localStore.getBlock(it.cid)
     ))
 
+    # Extract succesfully received blocks
     let blocks = blockFuts
-      .filterIt((not it.failed) and it.read.isOk)
-      .mapIt(!it.read)
+      .filterIt(it.completed and it.read.isOk and it.read.get.isSome)
+      .mapIt(it.read.get.get)
 
     if blocks.len > 0:
       trace "Sending blocks to peer", peer = task.id, blocks = blocks.len
@@ -381,11 +387,15 @@ proc taskHandler*(b: BlockExcEngine, task: BlockExcPeerCtx) {.gcsafe, async.} =
         task.id,
         blocks)
 
-    # Remove successfully sent blocks
-    task.peerWants.keepIf(
-      proc(e: Entry): bool =
-        not blocks.anyIt( it.cid == e.cid )
-    )
+      # Remove successfully sent blocks
+      task.peerWants.keepIf(
+        proc(e: Entry): bool =
+          not blocks.anyIt( it.cid == e.cid )
+      )
+
+
+  # PART 2: Send to the peer prices of the blocks he wants to discover,
+  # if they present in our local store
 
   var wants: seq[BlockPresence]
   # do not remove wants from the queue unless
@@ -393,7 +403,7 @@ proc taskHandler*(b: BlockExcEngine, task: BlockExcPeerCtx) {.gcsafe, async.} =
   for e in task.peerWants:
     if e.wantType == WantType.wantHave:
       var presence = Presence(cid: e.cid)
-      presence.have = b.localStore.hasblock(presence.cid)
+      presence.have = await (presence.cid in b.localStore)
       if presence.have and price =? b.pricing.?price:
         presence.price = price
       wants.add(BlockPresence.init(presence))
diff --git a/codex/blocktype.nim b/codex/blocktype.nim
index f16d155f..081acdc2 100644
--- a/codex/blocktype.nim
+++ b/codex/blocktype.nim
@@ -21,6 +21,14 @@ import pkg/questionable/results
 
 import ./errors
 
+const
+  BlockSize* = 31 * 64 * 4 # block size
+
+type
+  Block* = ref object of RootObj
+    cid*: Cid
+    data*: seq[byte]
+
 template EmptyCid*: untyped =
   var
     emptyCid {.global, threadvar.}:
@@ -90,14 +98,6 @@ template EmptyBlock*: untyped =
 
   emptyBlock
 
-const
-  BlockSize* = 31 * 64 * 4 # block size
-
-type
-  Block* = ref object of RootObj
-    cid*: Cid
-    data*: seq[byte]
-
 proc isEmpty*(cid: Cid): bool =
   cid == EmptyCid[cid.cidver]
   .catch
diff --git a/codex/erasure/erasure.nim b/codex/erasure/erasure.nim
index 87fc6a17..01401f2b 100644
--- a/codex/erasure/erasure.nim
+++ b/codex/erasure/erasure.nim
@@ -114,10 +114,14 @@ proc encode*(
       for j in 0..<blocks:
         let idx = blockIdx[j]
         if idx < manifest.len:
-          without var blk =? await dataBlocks[j], error:
-            trace "Unable to retrieve block", msg = error.msg
+          without blkOrNone =? await dataBlocks[j], error:
+            trace "Unable to retrieve block", error = error.msg
             return error.failure
 
+          without blk =? blkOrNone:
+            trace "Block not found", cid = encoded[idx]
+            return failure("Block not found")
+
           trace "Encoding block", cid = blk.cid, pos = idx
           shallowCopy(data[j], blk.data)
         else:
@@ -125,11 +129,11 @@ proc encode*(
           data[j] = newSeq[byte](manifest.blockSize)
 
       trace "Erasure coding data", data = data.len, parity = parityData.len
-      if (
-        let err = encoder.encode(data, parityData);
-        err.isErr):
-        trace "Unable to encode manifest!", err = $err.error
-        return failure($err.error)
+
+      let res = encoder.encode(data, parityData);
+      if res.isErr:
+        trace "Unable to encode manifest!", error = $res.error
+        return failure($res.error)
 
       for j in 0..<parity:
         let idx = encoded.rounded + blockIdx[j]
@@ -139,7 +143,7 @@ proc encode*(
 
         trace "Adding parity block", cid = blk.cid, pos = idx
         encoded[idx] = blk.cid
-        if not (await self.store.putBlock(blk)):
+        if isErr (await self.store.putBlock(blk)):
           trace "Unable to store block!", cid = blk.cid
           return failure("Unable to store block!")
   except CancelledError as exc:
@@ -205,10 +209,12 @@ proc decode*(
 
         idxPendingBlocks.del(idxPendingBlocks.find(done))
 
-        without blk =? (await done), error:
+        without blkOrNone =? (await done), error:
           trace "Failed retrieving block", exc = error.msg
+          return error.failure
 
-        if blk.isNil:
+        without blk =? blkOrNone:
+          trace "Block not found"
           continue
 
         if idx >= encoded.K:
@@ -242,7 +248,7 @@ proc decode*(
             return failure(error)
 
           trace "Recovered block", cid = blk.cid
-          if not (await self.store.putBlock(blk)):
+          if isErr (await self.store.putBlock(blk)):
             trace "Unable to store block!", cid = blk.cid
             return failure("Unable to store block!")
   except CancelledError as exc:
diff --git a/codex/node.nim b/codex/node.nim
index b234e07e..4bd3550c 100644
--- a/codex/node.nim
+++ b/codex/node.nim
@@ -66,9 +66,12 @@ proc retrieve*(
   cid: Cid): Future[?!LPStream] {.async.} =
 
   trace "Received retrieval request", cid
-  without blk =? await node.blockStore.getBlock(cid):
-    return failure(
-      newException(CodexError, "Couldn't retrieve block for Cid!"))
+  without blkOrNone =? await node.blockStore.getBlock(cid), error:
+    return failure(error)
+
+  without blk =? blkOrNone:
+    trace "Block not found", cid
+    return failure("Block not found")
 
   if manifest =? Manifest.decode(blk.data, blk.cid):
 
@@ -134,7 +137,7 @@ proc store*(
         return failure("Unable to init block from chunk!")
 
       blockManifest.add(blk.cid)
-      if not (await node.blockStore.putBlock(blk)):
+      if isErr (await node.blockStore.putBlock(blk)):
         # trace "Unable to store block", cid = blk.cid
         return failure("Unable to store block " & $blk.cid)
 
@@ -155,7 +158,7 @@ proc store*(
     trace "Unable to init block from manifest data!"
     return failure("Unable to init block from manifest data!")
 
-  if not (await node.blockStore.putBlock(manifest)):
+  if isErr (await node.blockStore.putBlock(manifest)):
     trace "Unable to store manifest", cid = manifest.cid
     return failure("Unable to store manifest " & $manifest.cid)
 
@@ -187,13 +190,17 @@ proc store(node: CodexNodeRef, cids: seq[Cid]): Future[?!void] {.async.} =
 proc store(node: CodexNodeRef, cid: Cid): Future[?!void] {.async.} =
   ## Retrieves dataset from the network, and stores it locally
 
-  if node.blockstore.hasBlock(cid):
+  without present =? await node.blockstore.hasBlock(cid):
+    return failure newException(CodexError, "Unable to find block " & $cid)
+  if present:
     return success()
 
-  without blk =? await node.blockstore.getBlock(cid):
+  without blkOrNone =? await node.blockstore.getBlock(cid):
+    return failure newException(CodexError, "Unable to retrieve block " & $cid)
+  without blk =? blkOrNone:
     return failure newException(CodexError, "Unable to retrieve block " & $cid)
 
-  if not (await node.blockstore.putBlock(blk)):
+  if isErr (await node.blockstore.putBlock(blk)):
     return failure newException(CodexError, "Unable to store block " & $cid)
 
   if manifest =? Manifest.decode(blk.data, blk.cid):
@@ -224,10 +231,14 @@ proc requestStorage*(self: CodexNodeRef,
     trace "Purchasing not available"
     return failure "Purchasing not available"
 
-  without blk =? (await self.blockStore.getBlock(cid)), error:
+  without blkOrNone =? (await self.blockStore.getBlock(cid)), error:
     trace "Unable to retrieve manifest block", cid
     return failure(error)
 
+  without blk =? blkOrNone:
+    trace "Manifest block not found", cid
+    return failure("Manifest block not found")
+
   without mc =? blk.cid.contentType():
     trace "Couldn't identify Cid!", cid
     return failure("Couldn't identify Cid! " & $cid)
@@ -254,7 +265,7 @@ proc requestStorage*(self: CodexNodeRef,
     trace "Unable to create block from encoded manifest"
     return failure(error)
 
-  if not (await self.blockStore.putBlock(encodedBlk)):
+  if isErr (await self.blockStore.putBlock(encodedBlk)):
     trace "Unable to store encoded manifest block", cid = encodedBlk.cid
     return failure("Unable to store encoded manifest block")
 
diff --git a/codex/stores/blockstore.nim b/codex/stores/blockstore.nim
index a7439f8d..478c818e 100644
--- a/codex/stores/blockstore.nim
+++ b/codex/stores/blockstore.nim
@@ -13,6 +13,7 @@ push: {.upraises: [].}
 
 import pkg/chronos
 import pkg/libp2p
+import pkg/questionable
 import pkg/questionable/results
 
 import ../blocktype
@@ -23,41 +24,39 @@ type
   OnBlock* = proc(cid: Cid): Future[void] {.upraises: [], gcsafe.}
   BlockStore* = ref object of RootObj
 
-method getBlock*(
-  b: BlockStore,
-  cid: Cid): Future[?!Block] {.base.} =
-  ## Get a block from the stores
+method getBlock*(self: BlockStore, cid: Cid): Future[?! (? Block)] {.base.} =
+  ## Get a block from the blockstore
   ##
 
   raiseAssert("Not implemented!")
 
-method putBlock*(
-  s: BlockStore,
-  blk: Block): Future[bool] {.base.} =
+method putBlock*(self: BlockStore, blk: Block): Future[?!void] {.base.} =
   ## Put a block to the blockstore
   ##
 
   raiseAssert("Not implemented!")
 
-method delBlock*(
-  s: BlockStore,
-  cid: Cid): Future[?!void] {.base.} =
+method delBlock*(self: BlockStore, cid: Cid): Future[?!void] {.base.} =
   ## Delete a block from the blockstore
   ##
 
   raiseAssert("Not implemented!")
 
-method hasBlock*(s: BlockStore, cid: Cid): bool {.base.} =
+method hasBlock*(self: BlockStore, cid: Cid): Future[?!bool] {.base.} =
   ## Check if the block exists in the blockstore
   ##
 
-  return false
+  raiseAssert("Not implemented!")
 
-method listBlocks*(s: BlockStore, onBlock: OnBlock): Future[void] {.base.} =
+method listBlocks*(self: BlockStore, onBlock: OnBlock): Future[?!void] {.base.} =
   ## Get the list of blocks in the BlockStore. This is an intensive operation
   ##
 
   raiseAssert("Not implemented!")
 
-proc contains*(s: BlockStore, blk: Cid): bool =
-  s.hasBlock(blk)
+proc contains*(self: BlockStore, blk: Cid): Future[bool] {.async.} =
+  ## Check if the block exists in the blockstore.
+  ## Return false if error encountered
+  ##
+
+  return (await self.hasBlock(blk)) |? false
diff --git a/codex/stores/cachestore.nim b/codex/stores/cachestore.nim
index e92ec50b..0dd7b7b3 100644
--- a/codex/stores/cachestore.nim
+++ b/codex/stores/cachestore.nim
@@ -44,34 +44,45 @@ const
   DefaultCacheSizeMiB* = 100
   DefaultCacheSize* = DefaultCacheSizeMiB * MiB # bytes
 
-method getBlock*(
-  self: CacheStore,
-  cid: Cid): Future[?!Block] {.async.} =
+method getBlock*(self: CacheStore, cid: Cid): Future[?! (? Block)] {.async.} =
   ## Get a block from the stores
   ##
 
   trace "Getting block from cache", cid
   if cid.isEmpty:
     trace "Empty block, ignoring"
-    return cid.emptyBlock.success
+    return cid.emptyBlock.some.success
 
-  return self.cache[cid].catch()
+  if cid notin self.cache:
+    return Block.none.success
 
-method hasBlock*(self: CacheStore, cid: Cid): bool =
-  ## check if the block exists
+  try:
+    let blk = self.cache[cid]
+    return blk.some.success
+  except CatchableError as exc:
+    trace "Exception requesting block", cid, exc = exc.msg
+    return failure(exc)
+
+method hasBlock*(self: CacheStore, cid: Cid): Future[?!bool] {.async.} =
+  ## Check if the block exists in the blockstore
   ##
 
-  trace "Checking for block presence in cache", cid
+  trace "Checking CacheStore for block presence", cid
   if cid.isEmpty:
     trace "Empty block, ignoring"
-    return true
+    return true.success
 
-  cid in self.cache
+  return (cid in self.cache).success
+
+method listBlocks*(s: CacheStore, onBlock: OnBlock): Future[?!void] {.async.} =
+  ## Get the list of blocks in the BlockStore. This is an intensive operation
+  ##
 
-method listBlocks*(s: CacheStore, onBlock: OnBlock) {.async.} =
   for cid in toSeq(s.cache.keys):
     await onBlock(cid)
 
+  return success()
+
 func putBlockSync(self: CacheStore, blk: Block): bool =
 
   let blkSize = blk.data.len # in bytes
@@ -94,22 +105,19 @@ func putBlockSync(self: CacheStore, blk: Block): bool =
   self.currentSize += blkSize
   return true
 
-method putBlock*(
-  self: CacheStore,
-  blk: Block): Future[bool] {.async.} =
+method putBlock*(self: CacheStore, blk: Block): Future[?!void] {.async.} =
   ## Put a block to the blockstore
   ##
 
   trace "Storing block in cache", cid = blk.cid
   if blk.isEmpty:
     trace "Empty block, ignoring"
-    return true
+    return success()
 
-  return self.putBlockSync(blk)
+  discard self.putBlockSync(blk)
+  return success()
 
-method delBlock*(
-  self: CacheStore,
-  cid: Cid): Future[?!void] {.async.} =
+method delBlock*(self: CacheStore, cid: Cid): Future[?!void] {.async.} =
   ## Delete a block from the blockstore
   ##
 
diff --git a/codex/stores/fsstore.nim b/codex/stores/fsstore.nim
index 5ec1bead..bb1630d1 100644
--- a/codex/stores/fsstore.nim
+++ b/codex/stores/fsstore.nim
@@ -37,67 +37,73 @@ type
 template blockPath*(self: FSStore, cid: Cid): string =
   self.repoDir / ($cid)[^self.postfixLen..^1] / $cid
 
-method getBlock*(
-  self: FSStore,
-  cid: Cid): Future[?!Block] {.async.} =
+method getBlock*(self: FSStore, cid: Cid): Future[?! (? Block)] {.async.} =
   ## Get a block from the stores
   ##
 
+  trace "Getting block from filestore", cid
   if cid.isEmpty:
     trace "Empty block, ignoring"
-    return cid.emptyBlock.success
+    return cid.emptyBlock.some.success
 
-  if cid in self.cache:
-    return await self.cache.getBlock(cid)
-
-  if cid notin self:
-    return Block.failure("Couldn't find block in fs store")
+  let cachedBlock = await self.cache.getBlock(cid)
+  if cachedBlock.isErr:
+    return cachedBlock
+  if cachedBlock.get.isSome:
+    trace "Retrieved block from cache", cid
+    return cachedBlock
 
+  # Read file contents
   var data: seq[byte]
-  let path = self.blockPath(cid)
-  if (
-    let res = io2.readFile(path, data);
-    res.isErr):
-    let error = io2.ioErrorMsg(res.error)
-    trace "Cannot read file from fs store", path , error
-    return Block.failure("Cannot read file from fs store")
+  let
+    path = self.blockPath(cid)
+    res = io2.readFile(path, data)
 
-  return Block.new(cid, data)
+  if res.isErr:
+    if not isFile(path):   # May be, check instead that "res.error == ERROR_FILE_NOT_FOUND" ?
+      return Block.none.success
+    else:
+      let error = io2.ioErrorMsg(res.error)
+      trace "Cannot read file from filestore", path, error
+      return failure("Cannot read file from filestore")
 
-method putBlock*(
-  self: FSStore,
-  blk: Block): Future[bool] {.async.} =
-  ## Put a block to the blockstore
+  without var blk =? Block.new(cid, data), error:
+    return error.failure
+
+  # TODO: add block to the cache
+  return blk.some.success
+
+method putBlock*(self: FSStore, blk: Block): Future[?!void] {.async.} =
+  ## Write block contents to file with name based on blk.cid,
+  ## save second copy to the cache
   ##
 
   if blk.isEmpty:
     trace "Empty block, ignoring"
-    return true
-
-  if blk.cid in self:
-    return true
-
-  # if directory exists it wont fail
-  if io2.createPath(self.blockPath(blk.cid).parentDir).isErr:
-    trace "Unable to create block prefix dir", dir = self.blockPath(blk.cid).parentDir
-    return false
+    return success()
 
   let path = self.blockPath(blk.cid)
-  if (
-    let res = io2.writeFile(path, blk.data);
-    res.isErr):
+  if isFile(path):
+    return success()
+
+  # If directory exists createPath wont fail
+  let dir = path.parentDir
+  if io2.createPath(dir).isErr:
+    trace "Unable to create block prefix dir", dir
+    return failure("Unable to create block prefix dir")
+
+  let res = io2.writeFile(path, blk.data)
+  if res.isErr:
     let error = io2.ioErrorMsg(res.error)
     trace "Unable to store block", path, cid = blk.cid, error
-    return false
+    return failure("Unable to store block")
 
-  if not (await self.cache.putBlock(blk)):
+  if isErr (await self.cache.putBlock(blk)):
     trace "Unable to store block in cache", cid = blk.cid
 
-  return true
+  return success()
 
-method delBlock*(
-  self: FSStore,
-  cid: Cid): Future[?!void] {.async.} =
+method delBlock*(self: FSStore, cid: Cid): Future[?!void] {.async.} =
   ## Delete a block from the blockstore
   ##
 
@@ -111,33 +117,35 @@ method delBlock*(
     res = io2.removeFile(path)
 
   if res.isErr:
-    let errmsg = io2.ioErrorMsg(res.error)
-    trace "Unable to delete block", path, cid, errmsg
-    return errmsg.failure
+    let error = io2.ioErrorMsg(res.error)
+    trace "Unable to delete block", path, cid, error
+    return error.failure
 
   return await self.cache.delBlock(cid)
 
-method hasBlock*(self: FSStore, cid: Cid): bool =
+method hasBlock*(self: FSStore, cid: Cid): Future[?!bool] {.async.} =
   ## Check if the block exists in the blockstore
   ##
 
-  trace "Checking for block existence", cid
+  trace "Checking filestore for block existence", cid
   if cid.isEmpty:
     trace "Empty block, ignoring"
-    return true
+    return true.success
 
-  self.blockPath(cid).isFile()
+  return self.blockPath(cid).isFile().success
 
-method listBlocks*(self: FSStore, onBlock: OnBlock) {.async.} =
-  debug "Listing all blocks in store"
+method listBlocks*(self: FSStore, onBlock: OnBlock): Future[?!void] {.async.} =
+  ## Get the list of blocks in the BlockStore. This is an intensive operation
+  ##
+
+  trace "Listing all blocks in filestore"
   for (pkind, folderPath) in self.repoDir.walkDir():
     if pkind != pcDir: continue
-    let baseName = basename(folderPath)
-    if baseName.len != self.postfixLen: continue
+    if len(folderPath.basename) != self.postfixLen: continue
 
-    for (fkind, filePath) in folderPath.walkDir(false):
+    for (fkind, filename) in folderPath.walkDir(relative = true):
       if fkind != pcFile: continue
-      let cid = Cid.init(basename(filePath))
+      let cid = Cid.init(filename)
       if cid.isOk:
         # getting a weird `Error: unhandled exception: index 1 not in 0 .. 0 [IndexError]`
         # compilation error if using different syntax/construct bellow
@@ -149,6 +157,8 @@ method listBlocks*(self: FSStore, onBlock: OnBlock) {.async.} =
         except CatchableError as exc:
           trace "Couldn't get block", cid = $(cid.get())
 
+  return success()
+
 proc new*(
   T: type FSStore,
   repoDir: string,
diff --git a/codex/stores/networkstore.nim b/codex/stores/networkstore.nim
index 5ce90d36..7d64a451 100644
--- a/codex/stores/networkstore.nim
+++ b/codex/stores/networkstore.nim
@@ -31,57 +31,57 @@ type
     engine*: BlockExcEngine # blockexc decision engine
     localStore*: BlockStore # local block store
 
-method getBlock*(
-  self: NetworkStore,
-  cid: Cid): Future[?!bt.Block] {.async.} =
+method getBlock*(self: NetworkStore, cid: Cid): Future[?! (? bt.Block)] {.async.} =
   ## Get a block from a remote peer
   ##
 
-  trace "Getting block", cid
-  without var blk =? (await self.localStore.getBlock(cid)):
-    trace "Couldn't get from local store", cid
-    try:
-      blk = await self.engine.requestBlock(cid)
-    except CatchableError as exc:
-      trace "Exception requesting block", cid, exc = exc.msg
-      return failure(exc.msg)
+  trace "Getting block from network store", cid
 
-  trace "Retrieved block from local store", cid
-  return blk.success
+  let blk = await self.localStore.getBlock(cid)
+  if blk.isErr:
+    return blk
+  if blk.get.isSome:
+    trace "Retrieved block from local store", cid
+    return blk
 
-method putBlock*(
-  self: NetworkStore,
-  blk: bt.Block): Future[bool] {.async.} =
-  ## Store block locally and notify the
-  ## network
+  trace "Block not found in local store", cid
+  try:
+    # TODO: What if block isn't available in the engine too?
+    let blk = await self.engine.requestBlock(cid)
+    # TODO: add block to the local store
+    return blk.some.success
+  except CatchableError as exc:
+    trace "Exception requesting block", cid, exc = exc.msg
+    return failure(exc)
+
+method putBlock*(self: NetworkStore, blk: bt.Block): Future[?!void] {.async.} =
+  ## Store block locally and notify the network
   ##
 
-  trace "Puting block", cid = blk.cid
+  trace "Puting block into network store", cid = blk.cid
 
-  if not (await self.localStore.putBlock(blk)):
-    return false
+  let res = await self.localStore.putBlock(blk)
+  if res.isErr:
+    return res
 
-  self.engine.resolveBlocks(@[blk])
-  return true
+  await self.engine.resolveBlocks(@[blk])
+  return success()
 
-method delBlock*(
-  self: NetworkStore,
-  cid: Cid): Future[?!void] =
+method delBlock*(self: NetworkStore, cid: Cid): Future[?!void] =
   ## Delete a block from the blockstore
   ##
 
-  trace "Deleting block from networkstore", cid
+  trace "Deleting block from network store", cid
   return self.localStore.delBlock(cid)
 
 {.pop.}
 
-method hasBlock*(
-  self: NetworkStore,
-  cid: Cid): bool =
+method hasBlock*(self: NetworkStore, cid: Cid): Future[?!bool] {.async.} =
   ## Check if the block exists in the blockstore
   ##
 
-  self.localStore.hasBlock(cid)
+  trace "Checking network store for block existence", cid
+  return await self.localStore.hasBlock(cid)
 
 proc new*(
   T: type NetworkStore,
diff --git a/codex/streams/storestream.nim b/codex/streams/storestream.nim
index 83958af9..54959924 100644
--- a/codex/streams/storestream.nim
+++ b/codex/streams/storestream.nim
@@ -7,6 +7,8 @@
 ## This file may not be copied, modified, or distributed except according to
 ## those terms.
 
+import std/options
+
 import pkg/upraises
 
 push: {.upraises: [].}
@@ -52,36 +54,40 @@ proc `size=`*(self: StoreStream, size: int)
   {.error: "Setting the size is forbidden".} =
   discard
 
+method atEof*(self: StoreStream): bool =
+  self.offset >= self.size
+
 method readOnce*(
   self: StoreStream,
   pbytes: pointer,
   nbytes: int): Future[int] {.async.} =
+  ## Read `nbytes` from current position in the StoreStream into output buffer pointed by `pbytes`.
+  ## Return how many bytes were actually read before EOF was encountered.
+  ## Raise exception if we are already at EOF.
 
+  trace "Reading from manifest", cid = self.manifest.cid.get(), blocks = self.manifest.len
   if self.atEof:
     raise newLPStreamEOFError()
 
-  var
-    read = 0
-
-  trace "Reading from manifest", cid = self.manifest.cid.get(), blocks = self.manifest.len
+  # The loop iterates over blocks in the StoreStream,
+  # reading them and copying their data into outbuf
+  var read = 0  # Bytes read so far, and thus write offset in the outbuf
   while read < nbytes and not self.atEof:
+    # Compute from the current stream position `self.offset` the block num/offset to read
+    # Compute how many bytes to read from this block
     let
-      pos = self.offset div self.manifest.blockSize
-      blk = (await self.store.getBlock(self.manifest[pos])).tryGet()
+      blockNum    = self.offset div self.manifest.blockSize
+      blockOffset = self.offset mod self.manifest.blockSize
+      readBytes   = min(nbytes - read, self.manifest.blockSize - blockOffset)
 
-      blockOffset =
-        if self.offset >= self.manifest.blockSize:
-          self.offset mod self.manifest.blockSize
-        else:
-          self.offset
+    # Read contents of block `blockNum`
+    without blkOrNone =? await self.store.getBlock(self.manifest[blockNum]), error:
+      raise newLPStreamReadError(error)
+    without blk =? blkOrNone:
+      raise newLPStreamReadError("Block not found")
+    trace "Reading bytes from store stream", blockNum, cid = blk.cid, bytes = readBytes, blockOffset
 
-      readBytes =
-        if (nbytes - read) >= (self.manifest.blockSize - blockOffset):
-          self.manifest.blockSize - blockOffset
-        else:
-          min(nbytes - read, self.manifest.blockSize)
-
-    trace "Reading bytes from store stream", pos, cid = blk.cid, bytes = readBytes, blockOffset = blockOffset
+    # Copy `readBytes` bytes starting at `blockOffset` from the block into the outbuf
     copyMem(
       pbytes.offset(read),
       if blk.isEmpty:
@@ -90,14 +96,12 @@ method readOnce*(
           blk.data[blockOffset].addr,
       readBytes)
 
+    # Update current positions in the stream and outbuf
     self.offset += readBytes
     read += readBytes
 
   return read
 
-method atEof*(self: StoreStream): bool =
-  self.offset >= self.manifest.len * self.manifest.blockSize
-
 method closeImpl*(self: StoreStream) {.async.} =
   try:
     trace "Closing StoreStream"
diff --git a/tests/codex/blockexchange/discovery/testdiscovery.nim b/tests/codex/blockexchange/discovery/testdiscovery.nim
index e71b78b3..3e63e674 100644
--- a/tests/codex/blockexchange/discovery/testdiscovery.nim
+++ b/tests/codex/blockexchange/discovery/testdiscovery.nim
@@ -82,7 +82,7 @@ suite "Block Advertising and Discovery":
 
     blockDiscovery.findBlockProvidersHandler =
       proc(d: MockDiscovery, cid: Cid): Future[seq[SignedPeerRecord]] {.async.} =
-        engine.resolveBlocks(blocks.filterIt( it.cid == cid ))
+        await engine.resolveBlocks(blocks.filterIt( it.cid == cid ))
 
     await allFuturesThrowing(
       allFinished(pendingBlocks))
diff --git a/tests/codex/blockexchange/engine/testblockexc.nim b/tests/codex/blockexchange/engine/testblockexc.nim
index b8c5f0a9..7371bf66 100644
--- a/tests/codex/blockexchange/engine/testblockexc.nim
+++ b/tests/codex/blockexchange/engine/testblockexc.nim
@@ -106,7 +106,7 @@ suite "NetworkStore engine - 2 nodes":
 
   test "Should send want-have for block":
     let blk = bt.Block.new("Block 1".toBytes).tryGet()
-    check await nodeCmps2.localStore.putBlock(blk)
+    (await nodeCmps2.localStore.putBlock(blk)).tryGet()
 
     let entry = Entry(
       `block`: blk.cid.data.buffer,
@@ -121,12 +121,12 @@ suite "NetworkStore engine - 2 nodes":
       .taskQueue
       .pushOrUpdateNoWait(peerCtx1).isOk
 
-    check eventually nodeCmps1.localStore.hasBlock(blk.cid)
+    check eventually (await nodeCmps1.localStore.hasBlock(blk.cid)).tryGet()
 
   test "Should get blocks from remote":
     let blocks = await allFinished(
       blocks2.mapIt( nodeCmps1.networkStore.getBlock(it.cid) ))
-    check blocks.mapIt( !it.read ) == blocks2
+    check blocks.mapIt( it.read().tryGet().get() ) == blocks2
 
   test "Remote should send blocks when available":
     let blk = bt.Block.new("Block 1".toBytes).tryGet()
@@ -137,7 +137,7 @@ suite "NetworkStore engine - 2 nodes":
 
     # second trigger blockexc to resolve any pending requests
     # for the block
-    check await nodeCmps2.networkStore.putBlock(blk)
+    (await nodeCmps2.networkStore.putBlock(blk)).tryGet()
 
     # should succeed retrieving block from remote
     check await nodeCmps1.networkStore.getBlock(blk.cid)
@@ -196,14 +196,8 @@ suite "NetworkStore - multiple nodes":
       pendingBlocks1 = blocks[0..3].mapIt( engine.pendingBlocks.getWantHandle( it.cid ) )
       pendingBlocks2 = blocks[12..15].mapIt( engine.pendingBlocks.getWantHandle( it.cid ))
 
-    await allFutures(
-      blocks[0..3].mapIt( networkStore[0].engine.localStore.putBlock(it) ))
-    await allFutures(
-      blocks[4..7].mapIt( networkStore[1].engine.localStore.putBlock(it) ))
-    await allFutures(
-      blocks[8..11].mapIt( networkStore[2].engine.localStore.putBlock(it) ))
-    await allFutures(
-      blocks[12..15].mapIt( networkStore[3].engine.localStore.putBlock(it) ))
+    for i in 0..15:
+      (await networkStore[i div 4].engine.localStore.putBlock(blocks[i])).tryGet()
 
     await connectNodes(switch)
     await sleepAsync(1.seconds)
@@ -232,14 +226,8 @@ suite "NetworkStore - multiple nodes":
       pendingBlocks1 = blocks[0..3].mapIt( engine.pendingBlocks.getWantHandle( it.cid ) )
       pendingBlocks2 = blocks[12..15].mapIt( engine.pendingBlocks.getWantHandle( it.cid ))
 
-    await allFutures(
-      blocks[0..3].mapIt( networkStore[0].engine.localStore.putBlock(it) ))
-    await allFutures(
-      blocks[4..7].mapIt( networkStore[1].engine.localStore.putBlock(it) ))
-    await allFutures(
-      blocks[8..11].mapIt( networkStore[2].engine.localStore.putBlock(it) ))
-    await allFutures(
-      blocks[12..15].mapIt( networkStore[3].engine.localStore.putBlock(it) ))
+    for i in 0..15:
+      (await networkStore[i div 4].engine.localStore.putBlock(blocks[i])).tryGet()
 
     await connectNodes(switch)
     await sleepAsync(1.seconds)
diff --git a/tests/codex/blockexchange/engine/testengine.nim b/tests/codex/blockexchange/engine/testengine.nim
index e6193e70..5fa2b803 100644
--- a/tests/codex/blockexchange/engine/testengine.nim
+++ b/tests/codex/blockexchange/engine/testengine.nim
@@ -227,8 +227,8 @@ suite "NetworkStore engine handlers":
       sendPresence: sendPresence
     ))
 
-    check await engine.localStore.putBlock(blocks[0])
-    check await engine.localStore.putBlock(blocks[1])
+    (await engine.localStore.putBlock(blocks[0])).tryGet()
+    (await engine.localStore.putBlock(blocks[1])).tryGet()
     await engine.wantListHandler(peerId, wantList)
 
     await done
@@ -242,7 +242,8 @@ suite "NetworkStore engine handlers":
     let resolved = await allFinished(pending)
     check resolved.mapIt( it.read ) == blocks
     for b in blocks:
-      check engine.localStore.hasBlock(b.cid)
+      let present = await engine.localStore.hasBlock(b.cid)
+      check present.tryGet()
 
   test "Should send payments for received blocks":
     let account = Account(address: EthAddress.example)
@@ -355,7 +356,7 @@ suite "Task Handler":
         blks[0].cid == blocks[1].cid
 
     for blk in blocks:
-      check await engine.localStore.putBlock(blk)
+      (await engine.localStore.putBlock(blk)).tryGet()
     engine.network.request.sendBlocks = sendBlocks
 
     # second block to send by priority
@@ -393,7 +394,7 @@ suite "Task Handler":
       ]
 
     for blk in blocks:
-      check await engine.localStore.putBlock(blk)
+      (await engine.localStore.putBlock(blk)).tryGet()
     engine.network.request.sendPresence = sendPresence
 
     # have block
diff --git a/tests/codex/helpers.nim b/tests/codex/helpers.nim
index 7dc22877..0b92f8df 100644
--- a/tests/codex/helpers.nim
+++ b/tests/codex/helpers.nim
@@ -1,3 +1,5 @@
+import std/options
+
 import pkg/chronos
 import pkg/libp2p
 import pkg/libp2p/varint
@@ -17,7 +19,7 @@ export randomchunker, nodeutils, mockdiscovery, eventually
 # is changed here, because blocks are now `ref`
 # types. This is only in tests!!!
 func `==`*(a, b: bt.Block): bool =
-  (a.cid == b.cid) and (a.data == b.  data)
+  (a.cid == b.cid) and (a.data == b.data)
 
 proc lenPrefix*(msg: openArray[byte]): seq[byte] =
   ## Write `msg` with a varint-encoded length prefix
@@ -45,7 +47,7 @@ proc corruptBlocks*(
 
     pos.add(i)
     var
-      blk = (await store.getBlock(manifest[i])).tryGet()
+      blk = (await store.getBlock(manifest[i])).tryGet().get()
       bytePos: seq[int]
 
     while true:
diff --git a/tests/codex/storageproofs/testnetwork.nim b/tests/codex/storageproofs/testnetwork.nim
index 10357ba1..f3e67954 100644
--- a/tests/codex/storageproofs/testnetwork.nim
+++ b/tests/codex/storageproofs/testnetwork.nim
@@ -65,12 +65,9 @@ suite "Storage Proofs Network":
       let chunk = await chunker.getBytes();
       chunk.len > 0):
 
-      let
-        blk = bt.Block.new(chunk).tryGet()
-
+      let blk = bt.Block.new(chunk).tryGet()
       manifest.add(blk.cid)
-      if not (await store.putBlock(blk)):
-        raise newException(CatchableError, "Unable to store block " & $blk.cid)
+      (await store.putBlock(blk)).tryGet()
 
     cid = manifest.cid.tryGet()
     por = await PoR.init(
diff --git a/tests/codex/storageproofs/testpor.nim b/tests/codex/storageproofs/testpor.nim
index 5b9c8481..b58e9590 100644
--- a/tests/codex/storageproofs/testpor.nim
+++ b/tests/codex/storageproofs/testpor.nim
@@ -36,12 +36,9 @@ suite "BLS PoR":
       let chunk = await chunker.getBytes();
       chunk.len > 0):
 
-      let
-        blk = bt.Block.new(chunk).tryGet()
-
+      let blk = bt.Block.new(chunk).tryGet()
       manifest.add(blk.cid)
-      if not (await store.putBlock(blk)):
-        raise newException(CatchableError, "Unable to store block " & $blk.cid)
+      (await store.putBlock(blk)).tryGet()
 
   test "Test PoR without corruption":
     let
@@ -97,12 +94,9 @@ suite "Test Serialization":
       let chunk = await chunker.getBytes();
       chunk.len > 0):
 
-      let
-        blk = bt.Block.new(chunk).tryGet()
-
+      let blk = bt.Block.new(chunk).tryGet()
       manifest.add(blk.cid)
-      if not (await store.putBlock(blk)):
-        raise newException(CatchableError, "Unable to store block " & $blk.cid)
+      (await store.putBlock(blk)).tryGet()
 
     (spk, ssk) = st.keyGen()
     por = await PoR.init(
diff --git a/tests/codex/storageproofs/teststpstore.nim b/tests/codex/storageproofs/teststpstore.nim
index 545ff68f..bca3739a 100644
--- a/tests/codex/storageproofs/teststpstore.nim
+++ b/tests/codex/storageproofs/teststpstore.nim
@@ -44,12 +44,9 @@ suite "Test PoR store":
       let chunk = await chunker.getBytes();
       chunk.len > 0):
 
-      let
-        blk = bt.Block.new(chunk).tryGet()
-
+      let blk = bt.Block.new(chunk).tryGet()
       manifest.add(blk.cid)
-      if not (await store.putBlock(blk)):
-        raise newException(CatchableError, "Unable to store block " & $blk.cid)
+      (await store.putBlock(blk)).tryGet()
 
     cid = manifest.cid.tryGet()
     por = await PoR.init(
diff --git a/tests/codex/stores/testcachestore.nim b/tests/codex/stores/testcachestore.nim
index 0a0d2fc6..000ebf58 100644
--- a/tests/codex/stores/testcachestore.nim
+++ b/tests/codex/stores/testcachestore.nim
@@ -1,4 +1,5 @@
 import std/strutils
+import std/options
 
 import pkg/chronos
 import pkg/asynctest
@@ -48,13 +49,13 @@ suite "Cache Store tests":
 
   test "putBlock":
 
-    check:
-      await store.putBlock(newBlock1)
-      newBlock1.cid in store
+    (await store.putBlock(newBlock1)).tryGet()
+    check (await store.hasBlock(newBlock1.cid)).tryGet()
 
     # block size bigger than entire cache
     store = CacheStore.new(cacheSize = 99, chunkSize = 98)
-    check not await store.putBlock(newBlock1)
+    (await store.putBlock(newBlock1)).tryGet()
+    check not (await store.hasBlock(newBlock1.cid)).tryGet()
 
     # block being added causes removal of LRU block
     store = CacheStore.new(
@@ -62,60 +63,63 @@ suite "Cache Store tests":
               cacheSize = 200,
               chunkSize = 1)
     check:
-      not store.hasBlock(newBlock1.cid)
-      store.hasBlock(newBlock2.cid)
-      store.hasBlock(newBlock3.cid)
+      not (await store.hasBlock(newBlock1.cid)).tryGet()
+      (await store.hasBlock(newBlock2.cid)).tryGet()
+      (await store.hasBlock(newBlock2.cid)).tryGet()
       store.currentSize == newBlock2.data.len + newBlock3.data.len # 200
 
   test "getBlock":
     store = CacheStore.new(@[newBlock])
 
     let blk = await store.getBlock(newBlock.cid)
-
-    check:
-      blk.isOk
-      blk.get == newBlock
+    check blk.tryGet().get() == newBlock
 
   test "fail getBlock":
     let blk = await store.getBlock(newBlock.cid)
-
-    check:
-      blk.isErr
-      blk.error of system.KeyError
+    check blk.tryGet().isNone()
 
   test "hasBlock":
     let store = CacheStore.new(@[newBlock])
-
-    check store.hasBlock(newBlock.cid)
+    check:
+      (await store.hasBlock(newBlock.cid)).tryGet()
+      await newBlock.cid in store
 
   test "fail hasBlock":
-    check not store.hasBlock(newBlock.cid)
+    check:
+      not (await store.hasBlock(newBlock.cid)).tryGet()
+      not (await newBlock.cid in store)
 
   test "delBlock":
     # empty cache
     (await store.delBlock(newBlock1.cid)).tryGet()
+    check not (await store.hasBlock(newBlock1.cid)).tryGet()
+
+    (await store.putBlock(newBlock1)).tryGet()
+    check (await store.hasBlock(newBlock1.cid)).tryGet()
 
     # successfully deleted
-    discard await store.putBlock(newBlock1)
     (await store.delBlock(newBlock1.cid)).tryGet()
+    check not (await store.hasBlock(newBlock1.cid)).tryGet()
 
     # deletes item should decrement size
     store = CacheStore.new(@[newBlock1, newBlock2, newBlock3])
     check:
       store.currentSize == 300
+
     (await store.delBlock(newBlock2.cid)).tryGet()
+
     check:
       store.currentSize == 200
-      newBlock2.cid notin store
+      not (await store.hasBlock(newBlock2.cid)).tryGet()
 
   test "listBlocks":
-    discard await store.putBlock(newBlock1)
+    (await store.putBlock(newBlock1)).tryGet()
 
     var listed = false
-    await store.listBlocks(
+    (await store.listBlocks(
       proc(cid: Cid) {.gcsafe, async.} =
-        check cid in store
+        check (await store.hasBlock(cid)).tryGet()
         listed = true
-    )
+    )).tryGet()
 
     check listed
diff --git a/tests/codex/stores/testfsstore.nim b/tests/codex/stores/testfsstore.nim
index 4089623e..2ec7b165 100644
--- a/tests/codex/stores/testfsstore.nim
+++ b/tests/codex/stores/testfsstore.nim
@@ -1,4 +1,5 @@
 import std/os
+import std/options
 
 import pkg/questionable
 import pkg/questionable/results
@@ -33,36 +34,43 @@ suite "FS Store":
     removeDir(repoDir)
 
   test "putBlock":
-    check await store.putBlock(newBlock)
-    check fileExists(store.blockPath(newBlock.cid))
-    check newBlock.cid in store
+    (await store.putBlock(newBlock)).tryGet()
+    check:
+      fileExists(store.blockPath(newBlock.cid))
+      (await store.hasBlock(newBlock.cid)).tryGet()
+      await newBlock.cid in store
 
   test "getBlock":
     createDir(store.blockPath(newBlock.cid).parentDir)
     writeFile(store.blockPath(newBlock.cid), newBlock.data)
     let blk = await store.getBlock(newBlock.cid)
-    check blk.option == newBlock.some
+    check blk.tryGet().get() == newBlock
 
   test "fail getBlock":
     let blk = await store.getBlock(newBlock.cid)
-    check blk.isErr
+    check blk.tryGet().isNone
 
   test "hasBlock":
     createDir(store.blockPath(newBlock.cid).parentDir)
     writeFile(store.blockPath(newBlock.cid), newBlock.data)
 
-    check store.hasBlock(newBlock.cid)
+    check:
+      (await store.hasBlock(newBlock.cid)).tryGet()
+      await newBlock.cid in store
+
+  test "fail hasBlock":
+    check:
+      not (await store.hasBlock(newBlock.cid)).tryGet()
+      not (await newBlock.cid in store)
 
   test "listBlocks":
     createDir(store.blockPath(newBlock.cid).parentDir)
     writeFile(store.blockPath(newBlock.cid), newBlock.data)
 
-    await store.listBlocks(
+    (await store.listBlocks(
       proc(cid: Cid) {.gcsafe, async.} =
-        check cid == newBlock.cid)
-
-  test "fail hasBlock":
-    check not store.hasBlock(newBlock.cid)
+        check cid == newBlock.cid
+    )).tryGet()
 
   test "delBlock":
     createDir(store.blockPath(newBlock.cid).parentDir)
diff --git a/tests/codex/testerasure.nim b/tests/codex/testerasure.nim
index 26e22475..4ece1823 100644
--- a/tests/codex/testerasure.nim
+++ b/tests/codex/testerasure.nim
@@ -37,7 +37,7 @@ suite "Erasure encode/decode":
 
       let blk = bt.Block.new(chunk).tryGet()
       manifest.add(blk.cid)
-      check (await store.putBlock(blk))
+      (await store.putBlock(blk)).tryGet()
 
   proc encode(buffers, parity: int): Future[Manifest] {.async.} =
     let
@@ -78,7 +78,8 @@ suite "Erasure encode/decode":
       decoded.len == encoded.originalLen
 
     for d in dropped:
-      check d in store
+      let present = await store.hasBlock(d)
+      check present.tryGet()
 
   test "Should not tolerate loosing more than M data blocks in a single random column":
     const
@@ -103,7 +104,8 @@ suite "Erasure encode/decode":
       decoded = (await erasure.decode(encoded)).tryGet()
 
     for d in dropped:
-      check d notin store
+      let present = await store.hasBlock(d)
+      check not present.tryGet()
 
   test "Should tolerate loosing M data blocks in M random columns":
     const
@@ -130,7 +132,8 @@ suite "Erasure encode/decode":
     discard (await erasure.decode(encoded)).tryGet()
 
     for d in manifest:
-      check d in store
+      let present = await store.hasBlock(d)
+      check present.tryGet()
 
   test "Should not tolerate loosing more than M data blocks in M random columns":
     const
@@ -179,7 +182,8 @@ suite "Erasure encode/decode":
     discard (await erasure.decode(encoded)).tryGet()
 
     for d in manifest:
-      check d in store
+      let present = await store.hasBlock(d)
+      check present.tryGet()
 
   test "Should tolerate loosing M (a.k.a row) contiguous parity blocks":
     const
@@ -194,7 +198,8 @@ suite "Erasure encode/decode":
     discard (await erasure.decode(encoded)).tryGet()
 
     for d in manifest:
-      check d in store
+      let present = await store.hasBlock(d)
+      check present.tryGet()
 
   test "handles edge case of 0 parity blocks":
     const
diff --git a/tests/codex/testnode.nim b/tests/codex/testnode.nim
index 98cbff01..71947cd8 100644
--- a/tests/codex/testnode.nim
+++ b/tests/codex/testnode.nim
@@ -85,10 +85,10 @@ suite "Test Node":
       manifestCid = (await storeFut).tryGet()
 
     check:
-      manifestCid in localStore
+      (await localStore.hasBlock(manifestCid)).tryGet()
 
     var
-      manifestBlock = (await localStore.getBlock(manifestCid)).tryGet()
+      manifestBlock = (await localStore.getBlock(manifestCid)).tryGet().get()
       localManifest = Manifest.decode(manifestBlock.data).tryGet()
 
     check:
@@ -104,20 +104,18 @@ suite "Test Node":
       let chunk = await chunker.getBytes();
       chunk.len > 0):
 
-      let
-        blk = bt.Block.new(chunk).tryGet()
-
+      let blk = bt.Block.new(chunk).tryGet()
       original &= chunk
-      check await localStore.putBlock(blk)
+      (await localStore.putBlock(blk)).tryGet()
       manifest.add(blk.cid)
 
     let
       manifestBlock = bt.Block.new(
-        manifest.encode().tryGet(),
-        codec = DagPBCodec)
-        .tryGet()
+          manifest.encode().tryGet(),
+          codec = DagPBCodec
+        ).tryGet()
 
-    check await localStore.putBlock(manifestBlock)
+    (await localStore.putBlock(manifestBlock)).tryGet()
 
     let stream = (await node.retrieve(manifestBlock.cid)).tryGet()
     var data: seq[byte]
@@ -125,9 +123,7 @@ suite "Test Node":
       var
         buf = newSeq[byte](BlockSize)
         res = await stream.readOnce(addr buf[0], BlockSize div 2)
-
       buf.setLen(res)
-
       data &= buf
 
     check data == original
@@ -137,7 +133,7 @@ suite "Test Node":
       testString = "Block 1"
       blk = bt.Block.new(testString.toBytes).tryGet()
 
-    check (await localStore.putBlock(blk))
+    (await localStore.putBlock(blk)).tryGet()
     let stream = (await node.retrieve(blk.cid)).tryGet()
 
     var data = newSeq[byte](testString.len)
diff --git a/tests/codex/teststorestream.nim b/tests/codex/teststorestream.nim
index 0a82785e..45311f31 100644
--- a/tests/codex/teststorestream.nim
+++ b/tests/codex/teststorestream.nim
@@ -16,6 +16,13 @@ suite "StoreStream":
     store: BlockStore
     stream: StoreStream
 
+  # Check that `buf` contains `size` bytes with values start, start+1...
+  proc sequential_bytes(buf: seq[byte], size: int, start: int): bool =
+    for i in 0..<size:
+      if int(buf[i]) != start+i:
+        return false
+    return true
+
   let
     data = [
       [byte 0, 1, 2, 3, 4, 5, 6, 7, 8, 9],
@@ -36,59 +43,63 @@ suite "StoreStream":
     stream = StoreStream.new(store, manifest)
 
     for d in data:
-      let
-        blk = bt.Block.new(d).tryGet()
-
+      let blk = bt.Block.new(d).tryGet()
       manifest.add(blk.cid)
-      if not (await store.putBlock(blk)):
-        raise newException(CatchableError, "Unable to store block " & $blk.cid)
+      (await store.putBlock(blk)).tryGet()
 
   test "Read all blocks < blockSize":
     var
       buf = newSeq[byte](8)
+      n = 0
 
     while not stream.atEof:
-      let
-        read = (await stream.readOnce(addr buf[0], buf.len))
+      let read = (await stream.readOnce(addr buf[0], buf.len))
 
-      if stream.atEof.not:
+      if not stream.atEof:
         check read == 8
       else:
         check read == 4
 
+      check sequential_bytes(buf,read,n)
+      n += read
+
   test "Read all blocks == blockSize":
     var
       buf = newSeq[byte](10)
+      n = 0
 
     while not stream.atEof:
-      let
-        read = (await stream.readOnce(addr buf[0], buf.len))
-
+      let read = (await stream.readOnce(addr buf[0], buf.len))
       check read == 10
+      check sequential_bytes(buf,read,n)
+      n += read
 
   test "Read all blocks > blockSize":
     var
       buf = newSeq[byte](11)
+      n = 0
 
     while not stream.atEof:
-      let
-        read = (await stream.readOnce(addr buf[0], buf.len))
+      let read = (await stream.readOnce(addr buf[0], buf.len))
 
-      if stream.atEof.not:
+      if not stream.atEof:
         check read == 11
       else:
         check read == 1
 
+      check sequential_bytes(buf,read,n)
+      n += read
+
   test "Read exact bytes within block boundary":
     var
       buf = newSeq[byte](5)
 
     await stream.readExactly(addr buf[0], 5)
-    check buf == [byte 0, 1, 2, 3, 4]
+    check sequential_bytes(buf,5,0)
 
   test "Read exact bytes outside of block boundary":
     var
       buf = newSeq[byte](15)
 
     await stream.readExactly(addr buf[0], 15)
-    check buf == [byte 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14]
+    check sequential_bytes(buf,15,0)