The successor RubyGem (with a more consistent gem name) is TestConstruct. Please report all issues there.

by Ben Brinckerhoff and Avdi Grimm
http://github.com/devver/construct

"This is the construct. It's our loading program. We can load anything, from clothing to equipment, weapons, and training simulations, anything we need" -- Morpheus

Construct is a DSL for creating temporary files and directories during testing.

class ExampleTest < Test::Unit::TestCase
  include Construct::Helpers

  def test_example
    within_construct do |c|
      c.directory 'alice/rabbithole' do |d|
        d.file 'white_rabbit.txt', "I'm late!"
        
        assert_equal "I'm late!", File.read('white_rabbit.txt')
      end
    end
  end

end

To use Construct, you need to include the Construct module in your class like so:

include Construct::Helpers

Using construct is as simple as calling within_construct and providing a block. All files and directories that are created within that block are created within a temporary directory. The temporary directory is always deleted before within_construct finishes.

There is nothing special about the files and directories created with Construct, so you can use plain old Ruby IO methods to interact with them.

The most basic use of Construct is creating an empty file with the:

within_construct do |construct|
  construct.file('foo.txt')
end

Note that the working directory is, by default, automatically change to the temporary directory created by Construct, so the following assertion will pass:

within_construct do |construct|
  construct.file('foo.txt')
  assert File.exist?('foo.txt')
end

You can also provide content for the file, either with an optional argument or using the return value of a supplied block:

within_construct do |construct|
  construct.file('foo.txt','Here is some content')
  construct.file('bar.txt') do
  <<-EOS
  The block will return this string, which will be used as the content.
  EOS
  end
end

If you provide block that accepts a parameter, construct will pass you the IO object. In this case, you are responsible for writing content to the file yourself - the return value of the block will not be used:

within_construct do |construct|
  construct.file('foo.txt') do |file|
    file << "Some content\n"
    file << "Some more content"
  end
end

Finally, you can provide the entire path to a file and the parent directories will be created automatically:

within_construct do |construct|
  construct.file('foo/bar/baz.txt')
end

It is easy to create a directory:

within_construct do |construct|
  construct.directory('foo')
end

You can also provide a block. The object passed to the block can be used to create nested files and directories (it's just a Pathname instance with some extra functionality, so you can use it to get the path of the current directory).

Again, note that the working directory is automatically changed while in the block:

within_construct do |construct|
  construct.directory('foo') do |dir|
    dir.file('bar.txt')
    assert File.exist?('bar.txt') # This assertion will pass
  end
end

Again, you can provide paths and the necessary directories will be automatically created:

within_construct do |construct|
  construct.directory('foo/bar/') do |dir|
    dir.directory('baz')
    dir.directory('bazz')
  end
end

Please read test/construct_test.rb for more examples.

gem install devver-construct --source http://gems.github.com

(The MIT License)

Copyright (c) 2009

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