How to test binary post uploaded file in rails?

I am currently testing if uploaded file is the same as original file. The api requires upload body to be binary, not multipart/form-data.

This is the spec:

  it "uploads" do
    fixture_path = Rails.root.join("spec/fixtures/")
    fixture_file = fixture_path.join("landscape.jpg")
    file = Rack::Test::UploadedFile.new(fixture_file, "image/jpeg", :binary)
    post api_upload_upload_path, file, header
    assert_response :success
  end

When I run the spec, it fails:

Failures:

  1) Api::V1::UploadController uploads
     Failure/Error: post api_upload_upload_path, file, company_header
     ArgumentError:
       invalid %-encoding (These are bad characters

How to fix this? or, Is there any better way to test this kind of action?

I've figured it out. It's because browser is hard to post an image. AngularJS puts it into multipart/form-data.