Basic setup for an RSpec based benchmark suite

This benchmark suite uses benchmark-ips
(https://github.com/evanphx/benchmark-ips) behind the scenes. Specs can
be turned into benchmark specs by setting "benchmark" to "true" in the
top-level describe block like so:

    describe SomeClass, benchmark: true do

    end

Writing benchmarks can be done using custom RSpec matchers, for example:

    describe MaruTheCat, benchmark: true do
      describe '#jump_in_box' do
        it 'should run 1000 iterations per second' do
          maru = described_class.new

          expect { maru.jump_in_box }.to iterate_per_second(1000)
        end
      end
    end

By default the "iterate_per_second" expectation requires a standard
deviation under 30% (this is just an arbitrary default for now). You can
change this by chaining "with_maximum_stddev" on the expectation:

    expect { maru.jump_in_box }.to iterate_per_second(1000)
      .with_maximum_stddev(10)

This will change the expectation to require a maximum deviation of 10%.

Alternatively you can use the it block style to write specs:

    describe MaruTheCat, benchmark: true do
      describe '#jump_in_box' do
        subject { -> { described_class.new } }

        it { is_expected.to iterate_per_second(1000) }
      end
    end

Because "iterate_per_second" operates on a block, opposed to a static
value, the "subject" method must return a Proc. This looks a bit goofy
but I have been unable to find a nice way around this.

1 files changed, 7 insertions, 0 deletions

diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index ddf4e31204a..a9aaf82ec1f 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -24,6 +24,13 @@ spec:api:
     - ruby
     - mysql
 
+spec:benchmark:
+  script:
+    - RAILS_ENV=test bundle exec rake spec:benchmark
+  tags:
+    - ruby
+    - mysql
+
 spec:other:
   script:
     - RAILS_ENV=test SIMPLECOV=true bundle exec rake spec:other