1 files changed, 6 insertions, 4 deletions
diff --git a/spec/ruby/core/array/pack/w_spec.rb b/spec/ruby/core/array/pack/w_spec.rb
index 439fa02198..263e2a2288 100644
--- a/spec/ruby/core/array/pack/w_spec.rb
+++ b/spec/ruby/core/array/pack/w_spec.rb
@@ -1,4 +1,4 @@
-# -*- encoding: binary -*-
+# encoding: binary
 require_relative '../../../spec_helper'
 require_relative '../fixtures/classes'
 require_relative 'shared/basic'
@@ -24,8 +24,10 @@ describe "Array#pack with format 'w'" do
     [obj].pack("w").should == "\x05"
   end
 
-  it "ignores NULL bytes between directives" do
-    [1, 2, 3].pack("w\x00w").should == "\x01\x02"
+  it "raise ArgumentError for NULL bytes between directives" do
+    -> {
+      [1, 2, 3].pack("w\x00w")
+    }.should.raise(ArgumentError, /unknown pack directive/)
   end
 
   it "ignores spaces between directives" do
@@ -33,7 +35,7 @@ describe "Array#pack with format 'w'" do
   end
 
   it "raises an ArgumentError when passed a negative value" do
-    -> { [-1].pack("w") }.should raise_error(ArgumentError)
+    -> { [-1].pack("w") }.should.raise(ArgumentError)
   end
 
   it "returns a binary string" do