trying to get swift spec to be as awesome as rspec

spec.swift

class RawOSMDataTests: QuickSpec {
  override func spec() {
    context("given a RawOSMData") {
      var subject: () -> RawOSMData? = { return nil }

      describe(".decode") {
        var json: String? = ""
        afterEach { json = nil }

        beforeEach {
          subject = { return RawOSMData.decode(from: json!) }
        }

        context("when json is invalid") {
          beforeEach {
            json = "foobar"
          }

          it("is nil") {
            expect(subject()).to(beNil())
          }
        }

        context("when json has a way") {
          beforeEach {
            json = """
            {
              "elements": [
                {
                  "id": 1,
                  "tags": {
                    "name": "Prenzlauer Allee"
                  },
                  "type": "way",
                }
              ]
            }
            """
          }

          it("has a name") {
            let name: String = subject()?.elements.first?.tags?.name ?? ""
            expect(name).to(equal("Prenzlauer Allee"))
          }
        }
      }
    }
  }
}