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require_relative '../../spec_helper'
require_relative 'fixtures/classes'
describe "Hash#compare_by_identity" do
before :each do
@h = {}
@idh = {}.compare_by_identity
end
it "causes future comparisons on the receiver to be made by identity" do
@h[[1]] = :a
@h[[1]].should == :a
@h.compare_by_identity
@h[[1].dup].should be_nil
end
it "rehashes internally so that old keys can be looked up" do
h = {}
(1..10).each { |k| h[k] = k }
o = Object.new
def o.hash; 123; end
h[o] = 1
h.compare_by_identity
h[o].should == 1
end
it "returns self" do
h = {}
h[:foo] = :bar
h.compare_by_identity.should equal h
end
it "has no effect on an already compare_by_identity hash" do
@idh[:foo] = :bar
@idh.compare_by_identity.should equal @idh
@idh.should.compare_by_identity?
@idh[:foo].should == :bar
end
it "uses the semantics of BasicObject#equal? to determine key identity" do
[1].should_not equal([1])
@idh[[1]] = :c
@idh[[1]] = :d
:bar.should equal(:bar)
@idh[:bar] = :e
@idh[:bar] = :f
@idh.values.should == [:c, :d, :f]
end
it "uses #equal? semantics, but doesn't actually call #equal? to determine identity" do
obj = mock('equal')
obj.should_not_receive(:equal?)
@idh[:foo] = :glark
@idh[obj] = :a
@idh[obj].should == :a
end
it "does not call #hash on keys" do
key = HashSpecs::ByIdentityKey.new
@idh[key] = 1
@idh[key].should == 1
end
it "regards #dup'd objects as having different identities" do
key = ['foo']
@idh[key.dup] = :str
@idh[key].should be_nil
end
it "regards #clone'd objects as having different identities" do
key = ['foo']
@idh[key.clone] = :str
@idh[key].should be_nil
end
it "regards references to the same object as having the same identity" do
o = Object.new
@h[o] = :o
@h[:a] = :a
@h[o].should == :o
end
it "raises a FrozenError on frozen hashes" do
@h = @h.freeze
-> { @h.compare_by_identity }.should raise_error(FrozenError)
end
# Behaviour confirmed in bug #1871
it "persists over #dups" do
@idh['foo'] = :bar
@idh['foo'] = :glark
@idh.dup.should == @idh
@idh.dup.size.should == @idh.size
end
it "persists over #clones" do
@idh['foo'] = :bar
@idh['foo'] = :glark
@idh.clone.should == @idh
@idh.clone.size.should == @idh.size
end
it "does not copy string keys" do
foo = 'foo'
@idh[foo] = true
@idh[foo] = true
@idh.size.should == 1
@idh.keys.first.should equal foo
end
it "gives different identity for string literals" do
@idh['foo'] = 1
@idh['foo'] = 2
@idh.values.should == [1, 2]
@idh.size.should == 2
end
end
describe "Hash#compare_by_identity?" do
it "returns false by default" do
h = {}
h.compare_by_identity?.should be_false
end
it "returns true once #compare_by_identity has been invoked on self" do
h = {}
h.compare_by_identity
h.compare_by_identity?.should be_true
end
it "returns true when called multiple times on the same ident hash" do
h = {}
h.compare_by_identity
h.compare_by_identity?.should be_true
h.compare_by_identity?.should be_true
h.compare_by_identity?.should be_true
end
end
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