Configuring an expectation framework

By default, RSpec is configured to include rspec-expectations for expressing desired outcomes. You can also configure RSpec to use:

Note that when you do not use rspec-expectations, you must explicitly provide a description to every example. You cannot rely on the generated descriptions provided by rspec-expectations.

Default configuration uses rspec-expectations

Given a file named “example_spec.rb” with:

RSpec::Matchers.define :be_a_multiple_of do |factor| match do |actual| actual % factor == 0 end end RSpec.describe 6 do it { is_expected.to be_a_multiple_of 3 } end

When I run rspec example_spec.rb

Then the examples should all pass.

Configure rspec-expectations (explicitly)

Given a file named “example_spec.rb” with:

RSpec.configure do |config| config.expect_with :rspec end RSpec.describe 5 do it "is greater than 4" do expect(5).to be > 4 end end

When I run rspec example_spec.rb

Then the examples should all pass.

Configure test/unit assertions

Given rspec-expectations is not installed

And a file named “example_spec.rb” with:

RSpec.configure do |config| config.expect_with :test_unit end RSpec.describe [1] do it "is equal to [1]" do assert_equal [1], [1], "expected [1] to equal [1]" end specify { assert_not_equal [1], [] } it "is equal to [2] (intentional failure)" do assert [1] == [2], "errantly expected [2] to equal [1]" end end

When I run rspec example_spec.rb

Then the output should match:

 (Test::Unit::AssertionFailedError|Mini(T|t)est::Assertion): errantly expected \[2\] to equal \[1\]

And the output should contain “3 examples, 1 failure”.

Configure minitest assertions

Given rspec-expectations is not installed

And a file named “example_spec.rb” with:

RSpec.configure do |config| config.expect_with :minitest end RSpec.describe "Object identity" do it "the an object is the same as itself" do x = [1] assert_same x, x, "expected x to be the same x" end specify { refute_same [1], [1] } it "is empty (intentional failure)" do assert_empty [1], "errantly expected [1] to be empty" end it "marks pending for skip method" do skip "intentionally" end end

When I run rspec -b example_spec.rb

Then the output should match:

 MiniT|test::Assertion: errantly expected \[1\] to be empty

And the output should contain “4 examples, 1 failure, 1 pending”

And the output should not contain “Warning: you should require ‘minitest/autorun’ instead.”.

Configure rspec/expectations AND test/unit assertions

Given a file named “example_spec.rb” with:

RSpec.configure do |config| config.expect_with :rspec, :test_unit end RSpec.describe [1] do it "is equal to [1]" do assert_equal [1], [1], "expected [1] to equal [1]" end it "matches array [1]" do is_expected.to match_array([1]) end end

When I run rspec example_spec.rb

Then the examples should all pass.

Configure rspec/expectations AND minitest assertions

Given a file named “example_spec.rb” with:

RSpec.configure do |config| config.expect_with :rspec, :minitest end RSpec.describe "Object identity" do it "two arrays are not the same object" do refute_same [1], [1] end it "an array is itself" do array = [1] expect(array).to be array end end

When I run rspec example_spec.rb

Then the examples should all pass.

Configure test/unit and minitest assertions

Given rspec-expectations is not installed

And a file named “example_spec.rb” with:

RSpec.configure do |config| config.expect_with :test_unit, :minitest end RSpec.describe [1] do it "is equal to [1]" do assert_equal [1], [1], "expected [1] to equal [1]" end specify { assert_not_equal [1], [] } it "the an object is the same as itself" do x = [1] assert_same x, x, "expected x to be the same x" end specify { refute_same [1], [1] } end

When I run rspec example_spec.rb

Then the examples should all pass.