Add specs for jruby/jruby#612

spec/ffi/struct_by_ref_spec.rb

@@ -0,0 +1,43 @@
+#
+# This file is part of ruby-ffi.
+# For licensing, see LICENSE.SPECS
+#
+
+require File.expand_path(File.join(File.dirname(__FILE__), "spec_helper"))
+
+describe FFI::Struct, ' by_ref' do
+  before :all do
+    @struct_class = struct_class = Class.new(FFI::Struct) do
+      layout :a, :pointer
+    end
+
+    @api = Module.new do 
+      extend FFI::Library
+      ffi_lib TestLibrary::PATH
+      fn = FFI::Type::POINTER.size == FFI::Type::LONG.size ? :ret_ulong : ret_uint64_t
+      attach_function :struct_test, fn, [ struct_class.by_ref ], :pointer
+    end
+  end
+
+  it "should accept instances of exact struct class" do
+    s = @struct_class.new
+    @api.struct_test(s).should == s.pointer
+  end
+
+  it "should accept nil" do
+    @api.struct_test(nil).should == nil
+  end
+
+  it "should reject other types" do
+    lambda { @api.struct_test('test').should == nil }.should raise_error(TypeError)
+  end
+
+  it "should reject instances of other struct classes" do
+    other_class = Class.new(FFI::Struct) do
+      layout :a, :pointer
+    end
+
+    lambda { @api.struct_test(other_class.new) }.should raise_error(TypeError)
+  end
+end
+