adding basic test for treehash algo

tests/dagger/helpers.nim

@@ -2,9 +2,22 @@ import pkg/libp2p/varint
 
 import pkg/dagger/chunker
 import pkg/dagger/blocktype
+import pkg/dagger/blockstream
+
+import pkg/questionable
+import pkg/questionable/results
 
 export chunker
 
+type
+  TestStreamProc* = proc(): ?!Block {.raises: [Defect].}
+
+  TestStream* = ref object of BlockStreamRef
+    handler*: TestStreamProc
+
+method nextBlock*(b: TestStream): ?!Block =
+  b.handler()
+
 proc lenPrefix*(msg: openArray[byte]): seq[byte] =
   ## Write `msg` with a varint-encoded length prefix
   ##

tests/dagger/testblockset.nim

@@ -12,17 +12,41 @@ import pkg/dagger/blocktype as bt
 import pkg/dagger/blockstream
 import pkg/dagger/blockset
 
+import ./helpers
+
 suite "Data set":
-  test "Make from Blocks":
+  test "Should produce valid tree hash checksum":
     let
-      blockStream = ChunkedBlockStreamRef.new(
-        newRandomChunker(Rng.instance(), size = 256 * 7, chunkSize = 256))
+      blocks = @[
+            !Block.new("Block 1".toBytes),
+            !Block.new("Block 2".toBytes),
+            !Block.new("Block 3".toBytes),
+            !Block.new("Block 4".toBytes),
+            !Block.new("Block 5".toBytes),
+            !Block.new("Block 6".toBytes),
+            !Block.new("Block 7".toBytes),
+          ]
+
+      checksum = @[byte(43), 2, 105, 202, 45, 227,
+                  178, 211, 83, 246, 56, 250, 210,
+                  160, 210, 98, 123, 87, 139, 157,
+                  188, 221, 252, 255, 17, 11, 79,
+                  85, 220, 161, 238, 108]
+
+    var idx = 0
+    proc nextBlockHandler(): ?!Block =
+      let blk = if idx < blocks.len: blocks[idx] else: return
+      idx.inc()
+      return success blk
+
+    let
+      blockStream = TestStream(handler: nextBlockHandler)
       blockSet = BlockSetRef.new(stream = blockStream)
 
     let res = blockSet.treeHash()
     check res.isOK
     if h =? res:
-      echo h.hashBytes()
+      check h.hashBytes() == checksum
       return
 
-    echo res.error.msg
+    check false