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Global namespace DSL

RSpec has a few top-level constructs that allow you to begin describing behaviour:

  • RSpec.describe: Define a named context for a group of examples.

  • RSpec.shared_examples: Define a set of shared examples that can later be included in an example group.

  • RSpec.shared_context: define some common context (using before, let, helper methods, etc) that can later be included in an example group.

Historically, these constructs have been available directly off of the main object, so that you could use these at the start of a file without the RSpec. prefix. They have also been available off of any class or module so that you can scope your examples within a particular constant namespace.

RSpec 3 now provides an option to disable this global monkey patching:

config.expose_dsl_globally = false

For backwards compatibility it defaults to true.

By default RSpec allows the DSL to be used globally​

Given a file named "spec/example_spec.rb" with:

describe "specs here" do
  it "passes" do
  end
end

When I run rspec

Then the output should contain "1 example, 0 failures".

By default rspec/autorun allows the DSL to be used globally​

Given a file named "spec/example_spec.rb" with:

require 'rspec/autorun'
describe "specs here" do
  it "passes" do
  end
end

When I run ruby spec/example_spec.rb

Then the output should contain "1 example, 0 failures".

When exposing globally is disabled the top level DSL no longer works​

Given a file named "spec/example_spec.rb" with:

RSpec.configure { |c| c.expose_dsl_globally = false }
describe "specs here" do
  it "passes" do
  end
end

When I run rspec

Then the output should contain "undefined method `describe'".

Regardless of setting​

Given a file named "spec/example_spec.rb" with:

RSpec.configure { |c| c.expose_dsl_globally = true }
RSpec.describe "specs here" do
  it "passes" do
  end
end

When I run rspec

Then the output should contain "1 example, 0 failures".