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author | Yorick Peterse <yorickpeterse@gmail.com> | 2015-10-02 18:00:23 +0300 |
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committer | Yorick Peterse <yorickpeterse@gmail.com> | 2015-10-02 18:00:23 +0300 |
commit | 19893a1c10e4e6dfbdb56ad78de1599b6c8f6981 (patch) | |
tree | 2e3b5b785d5053b851681f0ed61a8dcaf7578796 /spec/support | |
parent | dbc05d4a62468a8b7ebbeb17da4f74edaa09f968 (diff) |
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.
Diffstat (limited to 'spec/support')
-rw-r--r-- | spec/support/matchers/benchmark_matchers.rb | 42 |
1 files changed, 42 insertions, 0 deletions
diff --git a/spec/support/matchers/benchmark_matchers.rb b/spec/support/matchers/benchmark_matchers.rb new file mode 100644 index 00000000000..45a1d49345f --- /dev/null +++ b/spec/support/matchers/benchmark_matchers.rb @@ -0,0 +1,42 @@ +module BenchmarkMatchers + extend RSpec::Matchers::DSL + + matcher :iterate_per_second do |min_iterations| + supports_block_expectations + + match do |block| + @max_stddev ||= 30 + + @entry = benchmark(&block) + + expect(@entry.ips).to be >= min_iterations + expect(@entry.stddev_percentage).to be <= @max_stddev + end + + chain :with_maximum_stddev do |value| + @max_stddev = value + end + + description do + "run at least #{min_iterations} iterations per second" + end + + failure_message do + ips = @entry.ips.round(2) + stddev = @entry.stddev_percentage.round(2) + + "expected at least #{min_iterations} iterations per second " \ + "with a maximum stddev of #{@max_stddev}%, instead of " \ + "#{ips} iterations per second with a stddev of #{stddev}%" + end + end + + # Benchmarks the given block and returns a Benchmark::IPS::Report::Entry. + def benchmark(&block) + report = Benchmark.ips(quiet: true) do |bench| + bench.report(&block) + end + + report.entries[0] + end +end |