crypto: better error message for createHash

calling digest or update on a hash object after digest has been called
now gives a topical error message instead of an error message saying that the
hash failed to initialize.

PR-URL: https://github.com/nodejs/node/pull/6042
Reviewed-By: Brian White <mscdex@mscdex.net>
Reviewed-By: James M Snell <jasnell@gmail.com>

1 files changed, 12 insertions, 0 deletions

diff --git a/test/parallel/test-crypto-hash.js b/test/parallel/test-crypto-hash.js
index fce11eca04..b5fc7e881c 100644
--- a/test/parallel/test-crypto-hash.js
+++ b/test/parallel/test-crypto-hash.js
@@ -98,3 +98,15 @@ assert.equal(
 assert.notEqual(
     hutf8,
     crypto.createHash('sha512').update('УТФ-8 text', 'binary').digest('hex'));
+
+var h3 = crypto.createHash('sha256');
+h3.digest();
+assert.throws(function() {
+  h3.digest();
+},
+  /Digest already called/);
+
+assert.throws(function() {
+  h3.update('foo');
+},
+  /Digest already called/);