diff --git a/optional/capi/io_spec.rb b/optional/capi/io_spec.rb
index a34b3a4ff..dd3366427 100644
--- a/optional/capi/io_spec.rb
+++ b/optional/capi/io_spec.rb
@@ -579,11 +579,13 @@
       end
 
       it "does not apply the specified encoding flags" do
-        File.write("a.txt", "123\r\n456\n89")
-        file = File.open("a.txt", "r")
+        File.write(@name, "123\r\n456\n89")
+        file = File.open(@name, "r")
 
         io = @o.rb_io_open_descriptor(File, file.fileno, CApiIOSpecs::FMODE_READABLE, "a.txt", 60, "US-ASCII", "UTF-8", CApiIOSpecs::ECONV_UNIVERSAL_NEWLINE_DECORATOR, {})
         io.read_nonblock(20).should == "123\r\n456\n89"
+      ensure
+        file.close
       end
 
       it "ignores the IO open options" do
@@ -623,7 +625,13 @@
         io = @o.rb_io_open_descriptor(File, @w_io.fileno, CApiIOSpecs::FMODE_READABLE, "a.txt", 60, "US-ASCII", "UTF-8", 0, {})
         io.should.is_a?(File)
 
-        -> { io.read_nonblock(1) }.should raise_error(Errno::EBADF)
+        platform_is_not :windows do
+          -> { io.read_nonblock(1) }.should raise_error(Errno::EBADF)
+        end
+
+        platform_is :windows do
+          -> { io.read_nonblock(1) }.should raise_error(IO::EWOULDBLOCKWaitReadable)
+        end
       end
 
       it "tolerates NULL as rb_io_encoding *encoding parameter" do