require File.expand_path('../../../spec_helper', __FILE__) require File.expand_path('../fixtures/classes', __FILE__) describe "Array#sample" do it "samples evenly" do ary = [0, 1, 2, 3] 3.times do |i| counts = [0, 0, 0, 0] 4000.times do counts[ary.sample(3)[i]] += 1 end counts.each do |count| (800..1200).should include(count) end end end it "returns nil for an empty Array" do [].sample.should be_nil end it "returns a single value when not passed a count" do [4].sample.should equal(4) end it "returns an empty Array when passed zero" do [4].sample(0).should == [] end it "returns an Array of elements when passed a count" do [1, 2, 3, 4].sample(3).should be_an_instance_of(Array) end it "returns elements from the Array" do array = [1, 2, 3, 4] array.sample(3).all? { |x| array.should include(x) } end it "returns at most the number of elements in the Array" do array = [1, 2, 3, 4] result = array.sample(20) result.size.should == 4 end it "does not return the same value if the Array has unique values" do array = [1, 2, 3, 4] result = array.sample(20) result.sort.should == array end it "may return the same value if the array is not unique" do [4, 4].sample(2).should == [4,4] end it "calls #to_int to convert the count when passed an Object" do [1, 2, 3, 4].sample(mock_int(2)).size.should == 2 end it "raises ArgumentError when passed a negative count" do lambda { [1, 2].sample(-1) }.should raise_error(ArgumentError) end it "does not return subclass instances with Array subclass" do ArraySpecs::MyArray[1, 2, 3].sample(2).should be_an_instance_of(Array) end describe "with options" do it "calls #to_hash to convert the passed Object" do obj = mock("array_sample") obj.should_receive(:to_hash).and_return({}) obj.should_not_receive(:to_int) [1, 2].sample(obj).should be_an_instance_of(Fixnum) end it "calls #to_int on the first argument and #to_hash on the second when passed Objects" do count = mock("array_sample_count") count.should_receive(:to_int).and_return(2) options = mock("array_sample_options") options.should_receive(:to_hash).and_return({}) [1, 2].sample(count, options).size.should == 2 end it "calls #rand on the Object passed by the :random key in the arguments Hash" do obj = mock("array_sample_random") obj.should_receive(:rand).and_return(0.5) [1, 2].sample(random: obj).should be_an_instance_of(Fixnum) end it "raises a NoMethodError if an object passed for the RNG does not define #rand" do obj = BasicObject.new lambda { [1, 2].sample(random: obj) }.should raise_error(NoMethodError) end describe "when the object returned by #rand is a Fixnum" do it "uses the fixnum as index" do random = mock("array_sample_random_ret") random.should_receive(:rand).and_return(0) [1, 2].sample(random: random).should == 1 random = mock("array_sample_random_ret") random.should_receive(:rand).and_return(1) [1, 2].sample(random: random).should == 2 end it "raises a RangeError if the value is less than zero" do random = mock("array_sample_random") random.should_receive(:rand).and_return(-1) lambda { [1, 2].sample(random: random) }.should raise_error(RangeError) end it "raises a RangeError if the value is equal to the Array size" do random = mock("array_sample_random") random.should_receive(:rand).and_return(2) lambda { [1, 2].sample(random: random) }.should raise_error(RangeError) end end end describe "when the object returned by #rand is not a Fixnum but responds to #to_int" do it "calls #to_int on the Object" do value = mock("array_sample_random_value") value.should_receive(:to_int).and_return(1) random = mock("array_sample_random") random.should_receive(:rand).and_return(value) [1, 2].sample(random: random).should == 2 end it "raises a RangeError if the value is less than zero" do value = mock("array_sample_random_value") value.should_receive(:to_int).and_return(-1) random = mock("array_sample_random") random.should_receive(:rand).and_return(value) lambda { [1, 2].sample(random: random) }.should raise_error(RangeError) end it "raises a RangeError if the value is equal to the Array size" do value = mock("array_sample_random_value") value.should_receive(:to_int).and_return(2) random = mock("array_sample_random") random.should_receive(:rand).and_return(value) lambda { [1, 2].sample(random: random) }.should raise_error(RangeError) end end end