Minitest example

test.rb

require "minitest/autorun"

class TemplatingTest < Minitest::Test
  def test_positional_argument_splats
    assert_templates <<~RUBY, "h1", "*args"
      @_target << "<h1>" << _output(*args) << "</h1>"
    RUBY
  end

  def test_multiple_positional_argument_splats
    assert_templates <<~RUBY, "h1", "*a, *b"
      @_target << "<h1>" << _output(*a, *b) << "</h1>"
    RUBY
  end

  def test_a_variable
    assert_templates <<~RUBY, "h1", "name"
      @_target << "<h1>" << _output(name) << "</h1>"
    RUBY
  end

  private

  def some_compilation_method(tag, args)
    <<~RUBY
      @_target << "<#{tag}>" << _output(#{args}) << "</#{tag}>"
    RUBY
  end

  def assert_templates(expected, tag, args)
    assert_equal expected, some_compilation_method(tag, args)
  end
end