Customized message

RSpec tries to provide useful failure messages, but for cases in which you want more specific information, you can define your own message right in the example.This works for any matcher other than the operator matchers.

Customize failure message

Given a file named "example_spec.rb" with:

RSpec.describe Array do
  context "when created with `new`" do
    it "is empty" do
      array = Array.new
      array << 1 # trigger a failure to demonstrate the message
      expect(array).to be_empty, "expected empty array, got #{array.inspect}"
    end
  end
end

When I run rspec example_spec.rb --format documentation

Then the output should contain "expected empty array, got [1]".

Customize failure message with a proc

Given a file named "example_spec.rb" with:

RSpec.describe Array do
  context "when created with `new`" do
    it "is empty" do
      array = Array.new
      array << 1 # trigger a failure to demonstrate the message
      expect(array).to be_empty, lambda { "expected empty array, got #{array.inspect}" }
    end
  end
end

When I run rspec example_spec.rb --format documentation

Then the output should contain "expected empty array, got [1]".