Integrating with any test framework

* Include `RSpec::Mocks::ExampleMethods` in your test context. This provides rspec-mocks' API.
* Call `RSpec::Mocks.setup` before a test begins.
* Call `RSpec::Mocks.verify` after a test completes to verify message expectations. Note
  that this step is optional; rspec-core, for example, skips this when an example has already failed.
* Call `RSpec::Mocks.teardown` after a test completes (and after `verify`) to cleanup. This
  _must_ be called, even if an error has occurred, so it generally goes in an `ensure` clause.

require 'minitest/autorun'
require 'rspec/mocks'

module MinitestRSpecMocksIntegration
  include ::RSpec::Mocks::ExampleMethods

  def before_setup
    ::RSpec::Mocks.setup
    super
  end

  def after_teardown
    super
    ::RSpec::Mocks.verify
  ensure
    ::RSpec::Mocks.teardown
  end
end

Minitest::Test.send(:include, MinitestRSpecMocksIntegration)

require 'test_helper'

class RSpecMocksTest < Minitest::Test
  def test_passing_positive_expectation
    dbl = double
    expect(dbl).to receive(:message)
    dbl.message
  end

  def test_failing_positive_expectation
    dbl = double
    expect(dbl).to receive(:message)
  end

  def test_passing_negative_expectation
    dbl = double
    expect(dbl).to_not receive(:message)
  end

  def test_failing_negative_expectation
    dbl = double
    expect(dbl).to_not receive(:message)
    dbl.message
  end

  def test_passing_positive_spy_expectation
    bond = spy
    bond.james
    expect(bond).to have_received(:james)
  end

  def test_failing_positive_spy_expectation
    bond = spy
    expect(bond).to have_received(:james)
  end

  def test_passing_negative_spy_expectation
    bond = spy
    expect(bond).not_to have_received(:james)
  end

  def test_failing_negative_spy_expectation
    bond = spy
    bond.james
    expect(bond).not_to have_received(:james)
  end
end