1) RSpec::Mocks::Constant.original for a previously defined unstubbed constant indicates it was previously defined
Failure/Error: it("indicates it was previously defined") { expect(const).to be_previously_defined }
expected `#<RSpec::Mocks::Constant TestClass::M>.previously_defined?` to return true, got [:m, "TestClass::M"]
# ./spec/rspec/mocks/mutate_const_spec.rb:446:in `block (4 levels) in <module:Mocks>'