Re: Test-Driven Development in GUIs

On 6/7/05, Joe Van Dyk <[e-mail]> wrote:
> Hi,
> 
> Anyone have any tips for writing GUIs in Ruby (using Tk, for example)
> using a TDD approach?
> 
> A google search gave me
> http://approximity.com/ruby/rubytk.html#testfirst, which claims that
> some guy is writing a book on TDD for GUIs, using Ruby/Tk as preferred
> language/toolkit.  That section links to
> http://www.c2.com/cgi/wiki?TestFirstUserInterfaces, while informative,
> doesn't contain any information that I can see on a book.
> 
> Say, for the purposes of this discussion, say that you had a small Tk
> application that monitored the status of ten websites.  If the website
> was up and was active and performing well, the GUI would display a
> "Working!" message and perhaps showed data about the site (latency,
> bandwidth, whatever).  The GUI could also display graphs of
> uptime/downtime, view history reports, and moderately complex GUI
> stuff like that.
> 
> How would you go about testing that GUI application?  There's a strong
> chance that if I get some good ideas from my head and from this
> discussion, that I'd write that application and also write a HOWTO on
> TDD with GUIs.
> 
> Thanks,
> Joe
> 

Here's a very simple example of a quick UI app that's unit tested. 
Comments appreciated.

If you run the application like 'ruby file.rb test', the tests will
get run.  If you run it like 'ruby file.rb', the gui will be
displayed.  In a real application, the tests would be in their own
file, of course.

As I do more research, I'll post more examples.



require 'tk'
require 'test/unit'

class App
  attr_accessor :sum, :inc_button, :display_button, :power_2_button

  def initialize
    @sum = 0

    root = TkRoot.new :title => 'my app', :geometry => '300x300'

    @inc_button = TkButton.new(root, 
                             :text => "Increment!",
                             :command => proc { inc }
                             )
    @inc_button.pack :expand => true 

    @power_2_button = TkButton.new(root,
                                  :text => "Power of 2",
                                  :command => proc { power2 }
                                  )
    @power_2_button.pack :expand => true
  end

  def inc
    @sum += 1
    display
  end

  def power2
    @sum *= @sum
    display
  end

  def display
    puts  @sum
  end
end


class TestApp < Test::Unit::TestCase
  def testInc
    app = App.new

    assert_equal 0, app.sum

    app.inc_button.invoke
    assert_equal 1, app.sum

    app.inc_button.invoke
    assert_equal 2, app.sum
  end

  def testPower2
    app = App.new

    assert_equal 0, app.sum
    
    app.power_2_button.invoke
    assert_equal 0, app.sum

    app.inc_button.invoke
    assert_equal 1, app.sum

    app.power_2_button.invoke
    assert_equal 1, app.sum

    app.inc_button.invoke
    assert_equal 2, app.sum

    app.power_2_button.invoke
    app.power_2_button.invoke
    assert_equal 16, app.sum
  end
end

if ARGV[0] != 'test'
  App.new
  Tk.mainloop
  exit
end