blog__building-up-tests-via-context-and-let-in-ruby.rb

describe "#generate" do
  let(:subject) { described_class.generate(name, player) }
  let(:player) { Player.create(user_name: "Ronald McDonald", display_name: "Mac") }
  let(:name) { "Ronnie the Rat" }

  context "with defaults" do
    it { expect(subject.name).to eq name }
  end

  context "with nil player" do
    let(:player) { nil }
    it { expect(subject).to eq nil }
  end

  context "with other existing character" do
    before { described_class.generate(existing_name, existing_player) }
    let(:existing_player) { player }

    context "having a different name" do
      let(:existing_name) { "something else" }
      it { expect(subject).to be_present }
    end

    context "having the same name" do
      let(:existing_name) { name }
      it { expect { subject }.to raise_error "Character name already exists" }
      
      context "under a different player" do
        let(:existing_player) { Player.create(user_name: "existing", display_name: "existing") }
        it { expect(subject).to be_present }
      end
    end
  end

  context "with name containing invalid characters" do
    let(:name) { "#@!" }
    it { expect { subject }.to raise_error "Character name must be alphanumeric or spaces" }
  end
end