require_relative '../../spec_helper' describe "Array#max" do it "is defined on Array" do [1].method(:max).owner.should equal Array end it "returns nil with no values" do [].max.should == nil end it "returns only element in one element array" do [1].max.should == 1 end it "returns largest value with multiple elements" do [1,2].max.should == 2 [2,1].max.should == 2 end describe "given a block with one argument" do it "yields in turn the last length-1 values from the array" do ary = [] result = [1,2,3,4,5].max {|x| ary << x; x} ary.should == [2,3,4,5] result.should == 5 end end end # From Enumerable#max, copied for better readability describe "Array#max" do before :each do @a = [2, 4, 6, 8, 10] @e_strs = ["333", "22", "666666", "1", "55555", "1010101010"] @e_ints = [333, 22, 666666, 55555, 1010101010] end it "max should return the maximum element" do [18, 42].max.should == 42 [2, 5, 3, 6, 1, 4].max.should == 6 end it "returns the maximum element (basics cases)" do [55].max.should == 55 [11,99].max.should == 99 [99,11].max.should == 99 [2, 33, 4, 11].max.should == 33 [1,2,3,4,5].max.should == 5 [5,4,3,2,1].max.should == 5 [1,4,3,5,2].max.should == 5 [5,5,5,5,5].max.should == 5 ["aa","tt"].max.should == "tt" ["tt","aa"].max.should == "tt" ["2","33","4","11"].max.should == "4" @e_strs.max.should == "666666" @e_ints.max.should == 1010101010 end it "returns nil for an empty Enumerable" do [].max.should == nil end it "raises a NoMethodError for elements without #<=>" do -> do [BasicObject.new, BasicObject.new].max end.should raise_error(NoMethodError) end it "raises an ArgumentError for incomparable elements" do -> do [11,"22"].max end.should raise_error(ArgumentError) -> do [11,12,22,33].max{|a, b| nil} end.should raise_error(ArgumentError) end it "returns the maximum element (with block)" do # with a block ["2","33","4","11"].max {|a,b| a <=> b }.should == "4" [ 2 , 33 , 4 , 11 ].max {|a,b| a <=> b }.should == 33 ["2","33","4","11"].max {|a,b| b <=> a }.should == "11" [ 2 , 33 , 4 , 11 ].max {|a,b| b <=> a }.should == 2 @e_strs.max {|a,b| a.length <=> b.length }.should == "1010101010" @e_strs.max {|a,b| a <=> b }.should == "666666" @e_strs.max {|a,b| a.to_i <=> b.to_i }.should == "1010101010" @e_ints.max {|a,b| a <=> b }.should == 1010101010 @e_ints.max {|a,b| a.to_s <=> b.to_s }.should == 666666 end it "returns the minimum for enumerables that contain nils" do arr = [nil, nil, true] arr.max { |a, b| x = a.nil? ? 1 : a ? 0 : -1 y = b.nil? ? 1 : b ? 0 : -1 x <=> y }.should == nil end it "gathers whole arrays as elements when each yields multiple" do multi = [[1,2], [3,4,5], [6,7,8,9]] multi.max.should == [6, 7, 8, 9] end end