describe :hash_replace, shared: true do
  it "replaces the contents of self with other" do
    h = { a: 1, b: 2 }
    h.send(@method, c: -1, d: -2).should equal(h)
    h.should == { c: -1, d: -2 }
  end

  it "tries to convert the passed argument to a hash using #to_hash" do
    obj = mock('{1=>2,3=>4}')
    obj.should_receive(:to_hash).and_return({ 1 => 2, 3 => 4 })

    h = {}
    h.send(@method, obj)
    h.should == { 1 => 2, 3 => 4 }
  end

  it "calls to_hash on hash subclasses" do
    h = {}
    h.send(@method, HashSpecs::ToHashHash[1 => 2])
    h.should == { 1 => 2 }
  end

  it "does not transfer default values" do
    hash_a = {}
    hash_b = Hash.new(5)
    hash_a.send(@method, hash_b)
    hash_a.default.should == 5

    hash_a = {}
    hash_b = Hash.new { |h, k| k * 2 }
    hash_a.send(@method, hash_b)
    hash_a.default(5).should == 10

    hash_a = Hash.new { |h, k| k * 5 }
    hash_b = Hash.new(lambda { raise "Should not invoke lambda" })
    hash_a.send(@method, hash_b)
    hash_a.default.should == hash_b.default
  end

  it "raises a RuntimeError if called on a frozen instance that would not be modified" do
    lambda do
      HashSpecs.frozen_hash.send(@method, HashSpecs.frozen_hash)
    end.should raise_error(RuntimeError)
  end

  it "raises a RuntimeError if called on a frozen instance that is modified" do
    lambda do
      HashSpecs.frozen_hash.send(@method, HashSpecs.empty_frozen_hash)
    end.should raise_error(RuntimeError)
  end
end