route_spec.rb

describe 'something' do
  let(:route) { instance_double('Net::IP::Route', 'route') }
  before(:each) do
    allow(Net::IP::Route).to receive(:new).with({ test: 'data' }).and_return(route)
  end
  
  it 'doesn't suck' do
    expect(Net::IP).to receive(:routes).with(route)
    provider.create(context, name, {input: 'foo'})
  end
end

Switching to expect results in the same error.

Using pry, I don't see anything out of the ordinary, but seeing as puppet_munge is called by the create method, is allow(provider).to receive(:puppet_munge).with('should').and_return('munged') even the correct way to mock the results of that method?

none of the allows/expects are failing, it's failing specifically on provider.create() in the test. Almost like that line partially ignores the allows

Method being tested for reference purposes: https://github.com/dhollinger/puppet-network/blob/resource_refactor/lib/puppet/provider/network_route/network_route.rb#L78

To wrap up this thread, after some online debugging we found a missing stub, causing this.