feat(hashing): write test for merkle_root #146

Signed-off-by: Johns Beharry <johns@peakshift.com>

beacon_chain/utils/hashing/src/merkle_root.rs

@@ -0,0 +1,29 @@
+use types::{Hash256}
+use hashing::canonical_hash;
+
+fn merkle_root(values: Vec<>) -> Hash256 {
+    let o = values.len();
+
+    for v in &values {
+        canonical_hash(v.as_bytes());
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    #[test]
+    fn calculate_merkle_root() {
+        let values = vec!['abc', 'lmn', 'xyz', 'o0o'];
+
+        let test_leaf_1 = canonical_hash(values[0]);
+        let test_leaf_2 = canonical_hash(values[1]);
+        let test_leaf_3 = canonical_hash(values[2]);
+        let test_leaf_4 = canonical_hash(values[3]);
+        let test_node_1 = canonical_hash(vec![test_leaf_1, test_leaf_2]);
+        let test_node_2 = canonical_hash(vec![test_leaf_3, test_leaf_4]);
+        let test_root   = canonical_hash(vec![test_node_1, test_node_2]);
+
+        let result      = merkle_root(values);
+        assert_eq!(result, test_root);
+    }
+}