crypto: fix default encoding of LazyTransform

Change the default encoding from latin1 to utf8
and extend the test-crypto tests.

Author: Lukas Möller

lib/internal/crypto/lazy_transform.js

@@ -5,6 +5,7 @@
 
 const stream = require('stream');
 const util = require('util');
+const crypto = require('crypto');
 
 module.exports = LazyTransform;
 
@@ -22,7 +23,11 @@ util.inherits(LazyTransform, stream.Transform);
     get: function() {
       stream.Transform.call(this, this._options);
       this._writableState.decodeStrings = false;
-      this._writableState.defaultEncoding = 'latin1';
+
+      if (!this._options || !this._options.defaultEncoding) {
+        this._writableState.defaultEncoding = crypto.DEFAULT_ENCODING;
+      }
+
       return this[prop];
     },
     set: function(val) {

test/parallel/test-crypto.js

@@ -53,7 +53,6 @@ assert.throws(function() {
   crypto.createHash('sha1').update({foo: 'bar'});
 }, /buffer/);
 
-
 function assertSorted(list) {
   // Array#sort() modifies the list in place so make a copy.
   var sorted = util._extend([], list).sort();
@@ -141,3 +140,42 @@ assert.throws(function() {
 
 // Make sure memory isn't released before being returned
 console.log(crypto.randomBytes(16));
+
+/**
+ * Check if the stream function uses utf8 as a default encoding.
+ **/
+
+function testEncoding(options, assertionHash) {
+  const hash = crypto.createHash('sha256', options);
+  let hashValue = '';
+
+  hash.on('data', (data) => {
+    hashValue += data.toString('hex');
+  });
+
+  hash.on('end', () => {
+    assert.equal(hashValue, assertionHash);
+  });
+
+  hash.write('öäü');
+  hash.end();
+}
+
+// Hash of "öäü" in utf8 format
+const assertionHashUtf8 =
+  '4f53d15bee524f082380e6d7247cc541e7cb0d10c64efdcc935ceeb1e7ea345c';
+
+// Hash of "öäü" in ascii format
+const assertionHashAscii =
+  'cd37bccd5786e2e76d9b18c871e919e6eb11cc12d868f5ae41c40ccff8e44830';
+
+testEncoding(undefined, assertionHashUtf8);
+testEncoding({}, assertionHashUtf8);
+
+testEncoding({
+  defaultEncoding: 'utf8'
+}, assertionHashUtf8);
+
+testEncoding({
+  defaultEncoding: 'ascii'
+}, assertionHashAscii);