windows: add tests.

backtrace/test/crashpad_utils.rb

@@ -18,7 +18,7 @@ def listen_one
         }
         unless defined?(DEBUG)
             webrick_params = webrick_params.merge({
-                Logger: WEBrick::Log.new("/dev/null"),
+                Logger: WEBrick::Log.new(OS.windows? ? "NUL:" : "/dev/null"),
                 AccessLog: []
             })
         end

backtrace/test/test.rb

@@ -5,3 +5,4 @@
 
 require_relative 'test_linux' if OS.linux?
 require_relative 'test_macos' if OS.mac?
+require_relative 'test_windows' if OS.windows?

backtrace/test/test_windows.rb

@@ -0,0 +1,17 @@
+#!/usr/bin/ruby
+
+require_relative 'crashpad_utils'
+
+class TestLinux < Minitest::Test
+    def test_crashpad_uploads
+        result = Crashpad::perform_test executable: 'examples/windows/demo/Debug/demo_windows.exe'
+        assert result
+        assert result.has_key? :upload
+
+        payload = result[:upload].params
+
+        assert_equal payload.keys.sort, %w(format guid upload_file_minidump)
+
+        assert_equal payload['format'], 'minidump'
+    end
+end