Fix tests on browsers: need to add Buffer exception

lib/util/buffer.js

@@ -28,7 +28,7 @@ module.exports = {
    * @return {Buffer}
    */
   fill: function fill(buffer, value) {
-    $.checkArgumentType(buffer, Buffer, 'buffer');
+    $.checkArgumentType(buffer, 'Buffer', 'buffer');
     $.checkArgumentType(value, 'number', 'value');
     var length = buffer.length;
     for (var i = 0; i < length; i++) {
@@ -107,7 +107,7 @@ module.exports = {
    * @return {number}
    */
   integerFromBuffer: function integerFromBuffer(buffer) {
-    $.checkArgumentType(buffer, Buffer, 'buffer');
+    $.checkArgumentType(buffer, 'Buffer', 'buffer');
     return buffer[0] << 24 | buffer[1] << 16 | buffer[2] << 8 | buffer[3];
   },
 
@@ -117,7 +117,7 @@ module.exports = {
    * @return {number}
    */
   integerFromSingleByteBuffer: function integerFromBuffer(buffer) {
-    $.checkArgumentType(buffer, Buffer, 'buffer');
+    $.checkArgumentType(buffer, 'Buffer', 'buffer');
     return buffer[0];
   },
 
@@ -130,7 +130,7 @@ module.exports = {
    * @return {string}
    */
   bufferToHex: function bufferToHex(buffer) {
-    $.checkArgumentType(buffer, Buffer, 'buffer');
+    $.checkArgumentType(buffer, 'Buffer', 'buffer');
     return buffer.toString('hex');
   },
 
@@ -140,7 +140,7 @@ module.exports = {
    * @return {Buffer}
    */
   reverse: function reverse(param) {
-    $.checkArgumentType(param, Buffer, 'param');
+    $.checkArgumentType(param, 'Buffer', 'param');
     var ret = new buffer.Buffer(param.length);
     for (var i = 0; i < param.length; i++) {
       ret[i] = param[param.length - i - 1];

lib/util/preconditions.js

@@ -17,10 +17,12 @@ module.exports = {
   checkArgumentType: function(argument, type, argumentName) {
     argumentName = argumentName || '(unknown name)';
     if (_.isString(type)) {
-      if (type === 'number' && !_.isNumber(argument)) {
-        throw new errors.InvalidArgumentType(argument, type, argumentName);
-      }
-      if (typeof argument !== type) {
+      if (type === 'Buffer') {
+        var BufferUtil = require('./buffer');
+        if (!BufferUtil.isBuffer(argument)) {
+          throw new errors.InvalidArgumentType(argument, type, argumentName);
+        }
+      } else if (typeof argument !== type) {
         throw new errors.InvalidArgumentType(argument, type, argumentName);
       }
     } else {