Created: 2008-12-02 21:58
Updated: 2019-02-15 05:49

Ruby Slim

This package provides a SliM server implementing the FitNesse SliM protocol. It allows you to write test fixtures in Ruby, and invoke them from a FitNesse test.

Fixture names

Rubyslim is very particular about how your modules and classes are named, and how you import and use them in your FitNesse wiki:

  • Fixture folder must be lowercase_and_underscore
  • Fixture filenames must be lowercase_and_underscore
  • Ruby module name must be the CamelCase version of fixture folder name
  • Ruby class name must be the CamelCase version of the fixture file name

For example, this naming scheme is valid:

  • Folder: ruby_fix
  • Filename: my_fixture.rb
  • Module: RubyFix
  • Class: MyFixture

If you have TwoWords in CamelCase, then that would be two_words with underscores. If you have only oneword in the lowercase version, then you must have Oneword in the CamelCase version. If all of these naming conventions are not exactly followed, you'll get mysterious errors like Could not invoke constructor for your Slim tables.


Put these commands in a parent of the Ruby test pages.

!define TEST_SYSTEM {slim}
!define TEST_RUNNER {rubyslim}
!define COMMAND_PATTERN {rubyslim}
!path your/ruby/fixtures

Paths can be relative. You should put the following in an appropriate SetUp page:

|<ruby module of fixtures>|

You can have as many rows in this table as you like, one for each module that contains fixtures. Note that this needs to be the name of the module as written in the Ruby code, not the filename where the module is defined.

Ruby slim works a lot like Java slim. We tried to use ruby method naming conventions. So if you put this in a table:

|input|get output?|
|1    |2          |

Then it will call the set_input and get_output functions of the SomeDecisionTable class.

The SomeDecisionTable class would be written in a file called some_decision_table.rb, like this (the file name must correspond to the class name defined within, and the module name must match the one you are importing):

module MyModule
  class SomeDecisionTable
    def set_input(input)
      @x = input

    def get_output

Note that there is no type information for the arguments of these functions, so they will all be treated as strings. This is important to remember! All arguments are strings. If you are expecting integers, you will have to convert the strings to integers within your fixtures.


There is one exception to the above rule. If you pass a HashWidget in a table, then the argument will be converted to a Hash.

Consider, for example, this fixtures class:

module TestModule
  class TestSlimWithArguments
    def initialize(arg)
      @arg = arg

    def arg

    def name

    def addr

    def set_arg(hash)
      @arg = hash

This corresponds to the following tables.

|script|test slim with arguments|!{name:bob addr:here}|

|script|test slim with arguments|gunk|
|set arg|!{name:bob addr:here}|

Note the use of the HashWidgets in the table cells. These get translated into HTML, which RubySlim recognizes and converts to a standard ruby Hash.

System Under Test

If a fixture has a sut method that returns an object, then if a method called by a test is not found in the fixture itself, then if it exists in the object returned by sut it will be called. For example:

!|script|my fixture|

class MySystem
  def func(x)
    #this is the function that will be called.

class MyFixture
  attr_reader :sut

  def initialize
    @sut =

Since the fixture MyFixture does not have a function named func, but it does have a method named sut, RubySlim will try to call func on the object returned by sut.

Library Fixtures

Ruby Slim supports the |Library| feature of FitNesse. If you declare certain classes to be libraries, then if a test calls a method, and the specified fixture does not have it, and there is no specified sut, then the libraries will be searched in reverse order (latest first). If the method is found, then it is called.

For example:

|echo fixture|


class EchoFixture
  def echo(x)

Here, even though no fixture was specified for the script table, since a library was declared, functions will be called on it.

Cookies help us deliver our services. By using our services, you agree to our use of cookies Learn more