Add nvm_get_checksum_alg

test/fast/Unit tests/nvm_get_checksum_alg

@@ -0,0 +1,18 @@
+#!/bin/sh
+
+set -ex
+
+die () { echo $@ ; exit 1; }
+
+. ../../../nvm.sh
+
+ALG="$(nvm_get_checksum_alg)"
+
+case "$ALG" in
+  'sha-256' | 'sha-1')
+    echo 'sha-256 or sha-1 found'
+  ;;
+  *)
+    die "sha-256 or sha-1 not found: found ${ALG}"
+  ;;
+esac