Question

In a unit test I need to test whether alias methods defined by alias_method have been properly defined. I could simply use the same tests on the aliases used for their originals, but I’m wondering whether there’s a more definitive or efficient solution. For instance, is there a way to 1) dereference a method alias and return its original’s name, 2) get and compare some kind of underlying method identifier or address, or 3) get and compare method definitions? For example:

class MyClass
  def foo
    # do something
  end

  alias_method :bar, :foo
end

describe MyClass do
  it "method bar should be an alias for method foo" do
    m = MyClass.new
    # ??? identity(m.bar).should == identity(m.foo) ???
  end
end

Suggestions?

Answer 1

According to the documentation for Method,

Two method objects are equal if they
are bound to the same object and
contain the same body.

Calling Object#method and comparing the Method objects that it returns will verify that the methods are equivalent:

m.method(:bar) == m.method(:foo)