Demonstration of using built in matchers from within a custom matcher

output

Run options: include {:focus=>true}

All examples were filtered out; ignoring {:focus=>true}

Using built in matchers from custom ones
  fails when the word does not end with the given letter (FAILED - 1)
  fails when the word does not start with the given letter (FAILED - 2)
  can match properly

Failures:

  1) Using built in matchers from custom ones fails when the word does not end with the given letter
     Failure/Error: expect("poopin'").to start_and_end_with("p")
     expected "poopin'" to start and end with "p"
     # ./lib/rspec/expectations/fail_with.rb:33:in `fail_with'
     # ./lib/rspec/expectations/handler.rb:38:in `handle_failure'
     # ./lib/rspec/expectations/handler.rb:49:in `handle_matcher'
     # ./lib/rspec/expectations/expectation_target.rb:54:in `to'
     # ./spec/foo_spec.rb:18:in `block (2 levels) in <top (required)>'
     # /Users/myron/code/rspec-dev/repos/rspec-core/lib/rspec/core/example.rb:148:in `instance_exec'
     # /Users/myron/code/rspec-dev/repos/rspec-core/lib/rspec/core/example.rb:148:in `block in run'
     # /Users/myron/code/rspec-dev/repos/rspec-core/lib/rspec/core/example.rb:299:in `with_around_example_hooks'
     # /Users/myron/code/rspec-dev/repos/rspec-core/lib/rspec/core/example.rb:145:in `run'
     # /Users/myron/code/rspec-dev/repos/rspec-core/lib/rspec/core/example_group.rb:494:in `block in run_examples'
     # /Users/myron/code/rspec-dev/repos/rspec-core/lib/rspec/core/example_group.rb:490:in `map'
     # /Users/myron/code/rspec-dev/repos/rspec-core/lib/rspec/core/example_group.rb:490:in `run_examples'
     # /Users/myron/code/rspec-dev/repos/rspec-core/lib/rspec/core/example_group.rb:457:in `run'
     # /Users/myron/code/rspec-dev/repos/rspec-core/lib/rspec/core/runner.rb:112:in `block (2 levels) in run_specs'
     # /Users/myron/code/rspec-dev/repos/rspec-core/lib/rspec/core/runner.rb:112:in `map'
     # /Users/myron/code/rspec-dev/repos/rspec-core/lib/rspec/core/runner.rb:112:in `block in run_specs'
     # /Users/myron/code/rspec-dev/repos/rspec-core/lib/rspec/core/reporter.rb:49:in `report'
     # /Users/myron/code/rspec-dev/repos/rspec-core/lib/rspec/core/runner.rb:108:in `run_specs'
     # /Users/myron/code/rspec-dev/repos/rspec-core/lib/rspec/core/runner.rb:86:in `run'
     # /Users/myron/code/rspec-dev/repos/rspec-core/lib/rspec/core/runner.rb:70:in `run'
     # /Users/myron/code/rspec-dev/repos/rspec-core/lib/rspec/core/runner.rb:38:in `invoke'
     # /Users/myron/code/rspec-dev/repos/rspec-core/exe/rspec:4:in `<top (required)>'
     # ./bin/rspec:12:in `load'
     # ./bin/rspec:12:in `<main>'

  2) Using built in matchers from custom ones fails when the word does not start with the given letter
     Failure/Error: expect("apoop").to start_and_end_with("p")
     expected "apoop" to start and end with "p"
     # ./lib/rspec/expectations/fail_with.rb:33:in `fail_with'
     # ./lib/rspec/expectations/handler.rb:38:in `handle_failure'
     # ./lib/rspec/expectations/handler.rb:49:in `handle_matcher'
     # ./lib/rspec/expectations/expectation_target.rb:54:in `to'
     # ./spec/foo_spec.rb:14:in `block (2 levels) in <top (required)>'
     # /Users/myron/code/rspec-dev/repos/rspec-core/lib/rspec/core/example.rb:148:in `instance_exec'
     # /Users/myron/code/rspec-dev/repos/rspec-core/lib/rspec/core/example.rb:148:in `block in run'
     # /Users/myron/code/rspec-dev/repos/rspec-core/lib/rspec/core/example.rb:299:in `with_around_example_hooks'
     # /Users/myron/code/rspec-dev/repos/rspec-core/lib/rspec/core/example.rb:145:in `run'
     # /Users/myron/code/rspec-dev/repos/rspec-core/lib/rspec/core/example_group.rb:494:in `block in run_examples'
     # /Users/myron/code/rspec-dev/repos/rspec-core/lib/rspec/core/example_group.rb:490:in `map'
     # /Users/myron/code/rspec-dev/repos/rspec-core/lib/rspec/core/example_group.rb:490:in `run_examples'
     # /Users/myron/code/rspec-dev/repos/rspec-core/lib/rspec/core/example_group.rb:457:in `run'
     # /Users/myron/code/rspec-dev/repos/rspec-core/lib/rspec/core/runner.rb:112:in `block (2 levels) in run_specs'
     # /Users/myron/code/rspec-dev/repos/rspec-core/lib/rspec/core/runner.rb:112:in `map'
     # /Users/myron/code/rspec-dev/repos/rspec-core/lib/rspec/core/runner.rb:112:in `block in run_specs'
     # /Users/myron/code/rspec-dev/repos/rspec-core/lib/rspec/core/reporter.rb:49:in `report'
     # /Users/myron/code/rspec-dev/repos/rspec-core/lib/rspec/core/runner.rb:108:in `run_specs'
     # /Users/myron/code/rspec-dev/repos/rspec-core/lib/rspec/core/runner.rb:86:in `run'
     # /Users/myron/code/rspec-dev/repos/rspec-core/lib/rspec/core/runner.rb:70:in `run'
     # /Users/myron/code/rspec-dev/repos/rspec-core/lib/rspec/core/runner.rb:38:in `invoke'
     # /Users/myron/code/rspec-dev/repos/rspec-core/exe/rspec:4:in `<top (required)>'
     # ./bin/rspec:12:in `load'
     # ./bin/rspec:12:in `<main>'

Finished in 0.00146 seconds (files took 0.09554 seconds to load)
3 examples, 2 failures

Failed examples:

rspec ./spec/start_and_end_with_spec.rb:17 # Using built in matchers from custom ones fails when the word does not end with the given letter
rspec ./spec/start_and_end_with_spec.rb:13 # Using built in matchers from custom ones fails when the word does not start with the given letter

Randomized with seed 47699

start_and_end_with_spec.rb

describe "Using built in matchers from custom ones" do
  RSpec::Matchers.define :start_and_end_with do |letter|
    match do |string|
      expect(string).to start_with(letter)
      expect(string).to end_with(letter)
    end
  end

  it 'can match properly' do
    expect("poop").to start_and_end_with("p")
  end

  it 'fails when the word does not start with the given letter' do
    expect("apoop").to start_and_end_with("p")
  end

  it 'fails when the word does not end with the given letter' do
    expect("poopin'").to start_and_end_with("p")
  end
end