require_relative '../../spec_helper' ruby_version_is ""..."3.1" do require 'prime' describe :prime_each, shared: true do before :each do ScratchPad.record [] end it "enumerates primes" do primes = Prime.instance result = [] primes.each { |p| result << p break if p > 10 } result.should == [2, 3, 5, 7, 11] end it "yields ascending primes to the block" do previous = 1 @object.each do |prime| break if prime > 1000 ScratchPad << prime prime.should > previous previous = prime end all_prime = true ScratchPad.recorded.all? do |prime| all_prime &&= (2..Math.sqrt(prime)).all? { |d| prime % d != 0 } end all_prime.should be_true end it "returns the last evaluated expression in the passed block" do @object.each { break :value }.should equal(:value) end describe "when not passed a block" do before :each do @prime_enum = @object.each end it "returns an object that is Enumerable" do @prime_enum.each.should be_kind_of(Enumerable) end it "returns an object that responds to #with_index" do @prime_enum.should respond_to(:with_index) end it "returns an object that responds to #with_object" do @prime_enum.should respond_to(:with_object) end it "returns an object that responds to #next" do @prime_enum.should respond_to(:next) end it "returns an object that responds to #rewind" do @prime_enum.should respond_to(:rewind) end it "yields primes starting at 2 independent of prior enumerators" do @prime_enum.next.should == 2 @prime_enum.next.should == 3 @object.each { |prime| break prime }.should == 2 end it "returns an enumerator that yields previous primes when #rewind is called" do @prime_enum.next.should == 2 @prime_enum.next.should == 3 @prime_enum.rewind @prime_enum.next.should == 2 end it "returns independent enumerators" do enum = @object.each enum.next.should == 2 enum.next.should == 3 @prime_enum.next.should == 2 enum.next.should == 5 end end end describe :prime_each_with_arguments, shared: true do before :each do ScratchPad.record [] end it "yields ascending primes less than or equal to the argument" do bound = 1000 previous = 1 @object.each(bound) do |prime| ScratchPad << prime prime.should > previous previous = prime end ScratchPad.recorded.all? do |prime| (2..Math.sqrt(prime)).all? { |d| prime % d != 0 } end.should be_true ScratchPad.recorded.all? { |prime| prime <= bound }.should be_true end it "returns nil when no prime is generated" do @object.each(1) { :value }.should be_nil end it "yields primes starting at 2 independent of prior enumeration" do @object.each(10) { |prime| prime }.should == 7 @object.each(10) { |prime| break prime }.should == 2 end it "accepts a pseudo-prime generator as the second argument" do generator = mock('very bad pseudo-prime generator') generator.should_receive(:upper_bound=).with(100) generator.should_receive(:each).and_yield(2).and_yield(3).and_yield(4) @object.each(100, generator) { |prime| ScratchPad << prime } ScratchPad.recorded.should == [2, 3, 4] end describe "when not passed a block" do it "returns an object that returns primes less than or equal to the bound" do bound = 100 @object.each(bound).all? { |prime| prime <= bound }.should be_true end end end describe "Prime.each" do it_behaves_like :prime_each, :each, Prime end describe "Prime.each" do it_behaves_like :prime_each_with_arguments, :each, Prime end describe "Prime#each with Prime.instance" do it_behaves_like :prime_each, :each, Prime.instance end describe "Prime#each with Prime.instance" do it_behaves_like :prime_each_with_arguments, :each, Prime.instance end describe "Prime#each with Prime.instance" do before :each do @object = Prime.instance end it_behaves_like :prime_each, :each it "resets the enumerator with each call" do @object.each { |prime| break if prime > 10 } @object.each { |prime| break prime }.should == 2 end end end