Run Twist Scenarios from Rake

It is possible to export all the jars that Twist depends on. These jars can then be used to execute scenarios using tools such as Ant, Maven and Rake. The option to Export Twist Libraries is available in the Context Menu of a Twist project.

Here are the steps required to do this:

1. Export the dependencies of the project into a folder.
2. As tests are implemented in Java in Twist, and Rake is written in Ruby, we suggest that scenarios be executed using system calls. Here is how a typical Rake task would look:

task :execute_scenarios do
  
  # set these to the relative location of your project
  project_location = "."
  # the classes for the project are generated here
  project_output_location = File.expand_path(project_location, "bin")

  # the tags to execute
  tags = "!in-progress"
  # number of parallel threads to execute
  threads = "1"

  # you need not change anything below this
  # the dependencies required for executing the tests
  dependencies = Dir.glob("${exported_location}/twist-libs/*.jar")
  dependencies << "#{project_output_location}"
  classpath = dependencies.join(File::PATH_SEPARATOR) unless dependencies.empty?

  cmd_args = []
  cmd_args << "java"
  cmd_args << "-classpath"
  cmd_args << classpath
  cmd_args << "com.thoughtworks.twist.core.execution.ant.ScenarioExecutorAntMain"
  cmd_args << File.expand_path("#{project_location}", "scenarios")
  cmd_args << File.expand_path("#{project_location}", "reports")
  cmd_args << File.expand_path("#{project_location}", "twist-conf")
  cmd_args << "#{tags}"
  cmd_args << "#{threads}"

  system (cmd_args.join " ")

  raise "Twist tests failed" if $?.exitstatus
end