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require File.expand_path('../../../spec_helper', __FILE__)
require File.expand_path('../fixtures/classes', __FILE__)
describe "Array#first" do
it "returns the first element" do
%w{a b c}.first.should == 'a'
[nil].first.should == nil
end
it "returns nil if self is empty" do
[].first.should == nil
end
it "returns the first count elements if given a count" do
[true, false, true, nil, false].first(2).should == [true, false]
end
it "returns an empty array when passed count on an empty array" do
[].first(0).should == []
[].first(1).should == []
[].first(2).should == []
end
it "returns an empty array when passed count == 0" do
[1, 2, 3, 4, 5].first(0).should == []
end
it "returns an array containing the first element when passed count == 1" do
[1, 2, 3, 4, 5].first(1).should == [1]
end
it "raises an ArgumentError when count is negative" do
lambda { [1, 2].first(-1) }.should raise_error(ArgumentError)
end
it "raises a RangeError when count is a Bignum" do
lambda { [].first(bignum_value) }.should raise_error(RangeError)
end
it "returns the entire array when count > length" do
[1, 2, 3, 4, 5, 9].first(10).should == [1, 2, 3, 4, 5, 9]
end
it "returns an array which is independent to the original when passed count" do
ary = [1, 2, 3, 4, 5]
ary.first(0).replace([1,2])
ary.should == [1, 2, 3, 4, 5]
ary.first(1).replace([1,2])
ary.should == [1, 2, 3, 4, 5]
ary.first(6).replace([1,2])
ary.should == [1, 2, 3, 4, 5]
end
it "properly handles recursive arrays" do
empty = ArraySpecs.empty_recursive_array
empty.first.should equal(empty)
ary = ArraySpecs.head_recursive_array
ary.first.should equal(ary)
end
it "tries to convert the passed argument to an Integer using #to_int" do
obj = mock('to_int')
obj.should_receive(:to_int).and_return(2)
[1, 2, 3, 4, 5].first(obj).should == [1, 2]
end
it "raises a TypeError if the passed argument is not numeric" do
lambda { [1,2].first(nil) }.should raise_error(TypeError)
lambda { [1,2].first("a") }.should raise_error(TypeError)
obj = mock("nonnumeric")
lambda { [1,2].first(obj) }.should raise_error(TypeError)
end
it "does not return subclass instance when passed count on Array subclasses" do
ArraySpecs::MyArray[].first(0).should be_an_instance_of(Array)
ArraySpecs::MyArray[].first(2).should be_an_instance_of(Array)
ArraySpecs::MyArray[1, 2, 3].first(0).should be_an_instance_of(Array)
ArraySpecs::MyArray[1, 2, 3].first(1).should be_an_instance_of(Array)
ArraySpecs::MyArray[1, 2, 3].first(2).should be_an_instance_of(Array)
end
it "is not destructive" do
a = [1, 2, 3]
a.first
a.should == [1, 2, 3]
a.first(2)
a.should == [1, 2, 3]
a.first(3)
a.should == [1, 2, 3]
end
end
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