Class that allows testing of file uploads without an existing file.

documents_controller_spec.rb

require 'rails_helper'


describe DocumentsController do
  it 'uploads a file' do
    post :create, document: {
      name: 'test',
      doc: Rack::Test::UploadedFileData.new(
        "some content",
        "test.txt",
        "text/plain"
      )
    }

    expect(Document.count).to eq(1)
  end
end

rack_test_uploaded_file_data.rb

# This goes into spec/support

require "tempfile"
module Rack
	module Test
		class UploadedFileData < UploadedFile

			attr_reader :tempfile

			def initialize(data,filename = "data", content_type ="text/plain", binary=false)
				@content_type = content_type
				@original_filename = filename
				@tempfile = Tempfile.new(filename)
				@tempfile.set_encoding("Binary") if @tempfile.respond_to?(:set_encoding)
				@tempfile.binmode if binary
				@tempfile.write(data)
				@tempfile.rewind
			end
		end
	end
end