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Compound Expectations

Matchers can be composed using and or or to make compound expectations.

Use and to chain expectations​

Given a file named "compound_and_matcher_spec.rb" with:

RSpec.describe "A compound `and` matcher" do
  let(:string) { "foo bar bazz" }

  it "passes when both are true" do
    expect(string).to start_with("foo").and end_with("bazz")
  end

  it "passes when using boolean AND `&` alias" do
    expect(string).to start_with("foo") & end_with("bazz")
  end

  it "fails when the first matcher fails" do
    expect(string).to start_with("bar").and end_with("bazz")
  end

  it "fails when the second matcher fails" do
    expect(string).to start_with("foo").and end_with("bar")
  end
end

When I run rspec compound_and_matcher_spec.rb

Then the output should contain "4 examples, 2 failures".

Use or to chain expectations​

Given a file named "stoplight_spec.rb" with:

class StopLight
  def color
    %w[ green yellow red ].shuffle.first
  end
end

RSpec.describe StopLight, "#color" do
  let(:light) { StopLight.new }
  it "is green, yellow or red" do
    expect(light.color).to eq("green").or eq("yellow").or eq("red")
  end

  it "passes when using boolean OR `|` alias" do
    expect(light.color).to eq("green") | eq("yellow") | eq("red")
  end
end

When I run rspec stoplight_spec.rb

Then the example should pass.