require_relative '../../spec_helper' require_relative 'fixtures/classes' describe "Enumerable#one?" do before :each do @empty = EnumerableSpecs::Empty.new @enum = EnumerableSpecs::Numerous.new @enum1 = EnumerableSpecs::Numerous.new(0, 1, 2, -1) @enum2 = EnumerableSpecs::Numerous.new(nil, false, true) end it "always returns false on empty enumeration" do @empty.should_not.one? @empty.one? { true }.should == false end it "raises an ArgumentError when more than 1 argument is provided" do -> { @enum.one?(1, 2, 3) }.should raise_error(ArgumentError) -> { [].one?(1, 2, 3) }.should raise_error(ArgumentError) -> { {}.one?(1, 2, 3) }.should raise_error(ArgumentError) end it "does not hide exceptions out of #each" do -> { EnumerableSpecs::ThrowingEach.new.one? }.should raise_error(RuntimeError) -> { EnumerableSpecs::ThrowingEach.new.one? { false } }.should raise_error(RuntimeError) end describe "with no block" do it "returns true if only one element evaluates to true" do [false, nil, true].one?.should be_true end it "returns false if two elements evaluate to true" do [false, :value, nil, true].one?.should be_false end it "returns false if all elements evaluate to false" do [false, nil, false].one?.should be_false end it "gathers whole arrays as elements when each yields multiple" do multi = EnumerableSpecs::YieldsMultiWithSingleTrue.new multi.one?.should be_false end end describe "with a block" do it "returns true if block returns true once" do [:a, :b, :c].one? { |s| s == :a }.should be_true end it "returns false if the block returns true more than once" do [:a, :b, :c].one? { |s| s == :a || s == :b }.should be_false end it "returns false if the block only returns false" do [:a, :b, :c].one? { |s| s == :d }.should be_false end it "does not hide exceptions out of the block" do -> { @enum.one? { raise "from block" } }.should raise_error(RuntimeError) end it "gathers initial args as elements when each yields multiple" do multi = EnumerableSpecs::YieldsMulti.new yielded = [] multi.one? { |e| yielded << e; false }.should == false yielded.should == [1, 3, 6] end it "yields multiple arguments when each yields multiple" do multi = EnumerableSpecs::YieldsMulti.new yielded = [] multi.one? { |*args| yielded << args; false }.should == false yielded.should == [[1, 2], [3, 4, 5], [6, 7, 8, 9]] end end describe 'when given a pattern argument' do it "calls `===` on the pattern the return value " do pattern = EnumerableSpecs::Pattern.new { |x| x == 1 } @enum1.one?(pattern).should == true pattern.yielded.should == [[0], [1], [2], [-1]] end it "always returns false on empty enumeration" do @empty.one?(Integer).should == false [].one?(Integer).should == false {}.one?(NilClass).should == false end it "does not hide exceptions out of #each" do -> { EnumerableSpecs::ThrowingEach.new.one?(Integer) }.should raise_error(RuntimeError) end it "returns true if the pattern returns a truthy value only once" do @enum2.one?(NilClass).should == true pattern = EnumerableSpecs::Pattern.new { |x| x == 2 } @enum1.one?(pattern).should == true [1, 2, 42, 3].one?(pattern).should == true pattern = EnumerableSpecs::Pattern.new { |x| x == [:b, 2] } {a: 1, b: 2}.one?(pattern).should == true end it "returns false if the pattern returns a truthy value more than once" do pattern = EnumerableSpecs::Pattern.new { |x| !x } @enum2.one?(pattern).should == false pattern.yielded.should == [[nil], [false]] [1, 2, 3].one?(Integer).should == false {a: 1, b: 2}.one?(Array).should == false end it "returns false if the pattern never returns a truthy value" do pattern = EnumerableSpecs::Pattern.new { |x| nil } @enum1.one?(pattern).should == false pattern.yielded.should == [[0], [1], [2], [-1]] [1, 2, 3].one?(pattern).should == false {a: 1}.one?(pattern).should == false end it "does not hide exceptions out of pattern#===" do pattern = EnumerableSpecs::Pattern.new { raise "from pattern" } -> { @enum.one?(pattern) }.should raise_error(RuntimeError) end it "calls the pattern with gathered array when yielded with multiple arguments" do multi = EnumerableSpecs::YieldsMulti.new pattern = EnumerableSpecs::Pattern.new { false } multi.one?(pattern).should == false pattern.yielded.should == [[[1, 2]], [[3, 4, 5]], [[6, 7, 8, 9]]] end end end