From ecc4e50d28846dd8027cfaae0f8799c9409c96ac Mon Sep 17 00:00:00 2001
From: Mark Spanbroek <mark@spanbroek.net>
Date: Tue, 12 Jan 2021 13:43:23 +0100
Subject: [PATCH] Add root hash to Merkle DAG

---
 dagger.nimble                  |  1 +
 dagger/merkledag.nim           |  7 +++++++
 tests/dagger/testMerkleDag.nim | 11 +++++++++++
 tests/testAll.nim              |  1 +
 4 files changed, 20 insertions(+)
 create mode 100644 tests/dagger/testMerkleDag.nim

diff --git a/dagger.nimble b/dagger.nimble
index 6bea9c0c..5422c4eb 100644
--- a/dagger.nimble
+++ b/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"
diff --git a/dagger/merkledag.nim b/dagger/merkledag.nim
index 4466aba7..50441411 100644
--- a/dagger/merkledag.nim
+++ b/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()
diff --git a/tests/dagger/testMerkleDag.nim b/tests/dagger/testMerkleDag.nim
new file mode 100644
index 00000000..c18768b7
--- /dev/null
+++ b/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
diff --git a/tests/testAll.nim b/tests/testAll.nim
index bdf422a3..50d4f33a 100644
--- a/tests/testAll.nim
+++ b/tests/testAll.nim
@@ -1,3 +1,4 @@
+import ./dagger/testMerkleDag
 import ./dagger/testChunking
 import ./dagger/testDagger