happyrobots · June 5, 2011 20:34 · Nov 18, 2010 · Nov 18, 2010
diff --git a/benchmark.rb b/benchmark.rb
@@ -62,7 +62,7 @@ def benchmark(times = 1_000, &block)
 # Check if the execution average is close to expected.
 #
 #   it "should do something average time" do
-#     benchmark { do something }.should have_average(1.3, 0.01)
+#     benchmark { do something }.should be_on_average(1.3, 0.01)
 #   end
 #
 RSpec::Matchers.define :be_on_average do |expected, delta|

diff --git a/benchmark.rb b/benchmark.rb
@@ -0,0 +1,133 @@
+require "benchmark"
+require "rspec"
+
+module RSpec
+  module Benchmark
+    class Result
+      attr_accessor :slowest, :fastest, :average, :elapsed
+
+      def initialize(elapsed)
+        @elapsed = elapsed
+        @slowest = elapsed.max
+        @fastest = elapsed.min
+        @average = elapsed.inject(0) {|b, t| b + t} / elapsed.size
+      end
+
+      def to_s
+        "[average: #{average}, slowest: #{slowest}, fastest: #{fastest}]"
+      end
+    end
+
+    # Run a given block and calculate the average execution time.
+    # The block will be executed 1000 times by default.
+    #
+    #   benchmark { do something }
+    #   benchmark(100) { do something }
+    #
+    def benchmark(times = 1_000, &block)
+      elapsed = (1..times).collect do
+        GC.start
+        ::Benchmark.realtime(&block) * 1000
+      end
+
+      Result.new(elapsed)
+    end
+  end
+end
+
+# Check if the slowest execution is less than expected.
+#
+#   it "should do something fast" do
+#     benchmark { do something }.should be_faster_than(1.3)
+#   end
+#
+RSpec::Matchers.define :be_faster_than do |expected|
+  match do |result|
+    result.slowest < expected
+  end
+end
+
+# Check if the slowest execution is greater than expected.
+#
+#   it "should do something slow" do
+#     benchmark { do something }.should_not be_slower_than(1.3)
+#   end
+#
+RSpec::Matchers.define :be_slower_than do |expected|
+  match do |result|
+    result.slowest > expected
+  end
+end
+
+# Check if the execution average is close to expected.
+#
+#   it "should do something average time" do
+#     benchmark { do something }.should have_average(1.3, 0.01)
+#   end
+#
+RSpec::Matchers.define :be_on_average do |expected, delta|
+  match do |result|
+    (result.average - expected).abs < delta
+  end
+end
+
+# Include matchers and <tt>benchmark</tt> method into RSpec context.
+RSpec.configure do |config|
+  config.include(RSpec::Benchmark)
+end
+
+if ARGV[0] == __FILE__
+  describe RSpec::Benchmark do
+    before do
+      GC.stub(:start)
+    end
+
+    it "should be faster than expected" do
+      stub(:slowest => 0.01).should be_faster_than(0.5)
+    end
+
+    it "should not be faster than expected" do
+      stub(:slowest => 2).should_not be_faster_than(0.5)
+    end
+
+    it "should be slower than expected" do
+      stub(:slowest => 2).should be_slower_than(0.5)
+    end
+
+    it "should not be slower than expected" do
+      stub(:slowest => 0.5).should_not be_slower_than(2)
+    end
+
+    it "should be on average" do
+      stub(:average => 0.51).should be_on_average(0.5, 0.019)
+      stub(:average => 0.49).should be_on_average(0.5, 0.019)
+    end
+
+    it "should call garbage collector" do
+      GC.should_receive(:start).exactly(5).times
+      benchmark(5) { true }
+    end
+
+    it "should return result with collected data" do
+      result = benchmark(5) { true }
+
+      result.average.should be_kind_of(Float)
+      result.slowest.should be_kind_of(Float)
+      result.fastest.should be_kind_of(Float)
+    end
+
+    it "should run block" do
+      object = mock
+      object.should_receive(:run).exactly(1000).times
+
+      benchmark { object.run }
+    end
+
+    it "should run block with custom range" do
+      object = mock
+      object.should_receive(:run).exactly(3).times
+
+      benchmark(3) { object.run }
+    end
+  end
+end