rb: The shared binary protocol specs lacked a test for read_message_begin

git-svn-id: https://svn.apache.org/repos/asf/incubator/thrift/trunk@760637 13f79535-47bb-0310-9956-ffa450edef68
diff --git a/lib/rb/spec/binaryprotocol_spec_shared.rb b/lib/rb/spec/binaryprotocol_spec_shared.rb
index ee34964..a8a6e90 100644
--- a/lib/rb/spec/binaryprotocol_spec_shared.rb
+++ b/lib/rb/spec/binaryprotocol_spec_shared.rb
@@ -203,6 +203,11 @@
     lambda { @prot.write_string(nil) }.should raise_error
   end
   
+  it "should read message header correctly" do
+    @trans.write([protocol_class.const_get(:VERSION_1) | Thrift::MessageTypes::CALL, "testMessage".size, "testMessage", 17].pack("NNa11N"))
+    @prot.read_message_begin().should == ['testMessage', Thrift::MessageTypes::CALL, 17]
+  end
+  
   # message footer is a noop
   
   it "should read a field header" do