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ruby--ruby/spec/ruby/core/array/max_spec.rb
2019-07-27 12:40:09 +02:00

116 lines
2.9 KiB
Ruby

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