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require_relative '../../spec_helper'
require_relative 'fixtures/classes'
describe "Hash#to_h" do
it "returns self for Hash instances" do
h = {}
h.to_h.should equal(h)
end
describe "when called on a subclass of Hash" do
before :each do
@h = HashSpecs::MyHash.new
@h[:foo] = :bar
end
it "returns a new Hash instance" do
@h.to_h.should be_an_instance_of(Hash)
@h.to_h.should == @h
@h[:foo].should == :bar
end
it "retains the default" do
@h.default = 42
@h.to_h.default.should == 42
@h[:hello].should == 42
end
it "retains the default_proc" do
@h.default_proc = prc = Proc.new{ |h, k| h[k] = 2 * k }
@h.to_h.default_proc.should == prc
@h[42].should == 84
end
it "retains compare_by_identity flag" do
@h.compare_by_identity
@h.to_h.compare_by_identity?.should == true
end
end
context "with block" do
it "converts [key, value] pairs returned by the block to a hash" do
{ a: 1, b: 2 }.to_h { |k, v| [k.to_s, v*v]}.should == { "a" => 1, "b" => 4 }
end
it "passes to a block each pair's key and value as separate arguments" do
ScratchPad.record []
{ a: 1, b: 2 }.to_h { |k, v| ScratchPad << [k, v]; [k, v] }
ScratchPad.recorded.sort.should == [[:a, 1], [:b, 2]]
ScratchPad.record []
{ a: 1, b: 2 }.to_h { |*args| ScratchPad << args; [args[0], args[1]] }
ScratchPad.recorded.sort.should == [[:a, 1], [:b, 2]]
end
it "raises ArgumentError if block returns longer or shorter array" do
-> do
{ a: 1, b: 2 }.to_h { |k, v| [k.to_s, v*v, 1] }
end.should raise_error(ArgumentError, /element has wrong array length/)
-> do
{ a: 1, b: 2 }.to_h { |k, v| [k] }
end.should raise_error(ArgumentError, /element has wrong array length/)
end
it "raises TypeError if block returns something other than Array" do
-> do
{ a: 1, b: 2 }.to_h { |k, v| "not-array" }
end.should raise_error(TypeError, /wrong element type String/)
end
it "coerces returned pair to Array with #to_ary" do
x = mock('x')
x.stub!(:to_ary).and_return([:b, 'b'])
{ a: 1 }.to_h { |k| x }.should == { :b => 'b' }
end
it "does not coerce returned pair to Array with #to_a" do
x = mock('x')
x.stub!(:to_a).and_return([:b, 'b'])
-> do
{ a: 1 }.to_h { |k| x }
end.should raise_error(TypeError, /wrong element type MockObject/)
end
it "does not retain the default value" do
h = Hash.new(1)
h2 = h.to_h { |k, v| [k.to_s, v*v]}
h2.default.should be_nil
end
it "does not retain the default_proc" do
pr = proc { |h, k| h[k] = [] }
h = Hash.new(&pr)
h2 = h.to_h { |k, v| [k.to_s, v*v]}
h2.default_proc.should be_nil
end
it "does not retain compare_by_identity flag" do
h = { a: 9, c: 4 }.compare_by_identity
h2 = h.to_h { |k, v| [k.to_s, v*v]}
h2.compare_by_identity?.should == false
end
end
end
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