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require_relative '../../spec_helper'
describe "Array#sum" do
it "returns the sum of elements" do
[1, 2, 3].sum.should == 6
end
it "applies a block to each element before adding if it's given" do
[1, 2, 3].sum { |i| i * 10 }.should == 60
end
it "returns init value if array is empty" do
[].sum(-1).should == -1
end
it "returns 0 if array is empty and init is omitted" do
[].sum.should == 0
end
it "adds init value to the sum of elements" do
[1, 2, 3].sum(10).should == 16
end
it "can be used for non-numeric objects by providing init value" do
["a", "b", "c"].sum("").should == "abc"
end
it 'raises TypeError if any element are not numeric' do
-> { ["a"].sum }.should raise_error(TypeError)
end
it 'raises TypeError if any element cannot be added to init value' do
-> { [1].sum([]) }.should raise_error(TypeError)
end
it "calls + to sum the elements" do
a = mock("a")
b = mock("b")
a.should_receive(:+).with(b).and_return(42)
[b].sum(a).should == 42
end
end
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