Add root hash to Merkle DAG

dagger.nimble

@@ -4,5 +4,6 @@ description = "Dagger Storage Network"
 license = "MIT"
 
 requires "nim >= 1.4.2 & < 2.0.0"
+requires "libp2p >= 0.0.2 & < 0.1.0"
 requires "chronos >= 2.5.2 & < 3.0.0"
 requires "asynctest >= 0.2.1 & < 0.3.0"

dagger/merkledag.nim

@@ -1,3 +1,10 @@
+import pkg/libp2p/multihash
+
+export multihash
+
 type
   MerkleDag* = object
     data*: seq[byte]
+
+proc rootHash*(dag: MerkleDag): MultiHash =
+  MultiHash.digest("sha2-256", dag.data).get()

tests/dagger/testMerkleDag.nim

@@ -0,0 +1,11 @@
+import std/unittest
+import pkg/dagger/merkledag
+
+suite "Merkle DAG":
+
+  test "has a root hash":
+    let dag1 = MerkleDag(data: @[1'u8, 2'u8, 3'u8])
+    let dag2 = MerkleDag(data: @[4'u8, 5'u8, 6'u8])
+    let dag3 = MerkleDag(data: @[4'u8, 5'u8, 6'u8])
+    check dag1.rootHash != dag2.rootHash
+    check dag2.rootHash == dag3.rootHash

tests/testAll.nim

@@ -1,3 +1,4 @@
+import ./dagger/testMerkleDag
 import ./dagger/testChunking
 import ./dagger/testDagger