It("return the exit error", func() { err := sb.LaunchDNS(runner) Expect(err).To(MatchError("launch dns: unexpected server exit")) }) }) }) Describe("VethDeviceCount", func() { BeforeEach(func() { linkFactory.VethDeviceCountReturns(99, nil) }) It("returns gets veth device count from the sandbox", func() { sbNamespace.ExecuteStub = func(callback func(*os.File) error) error { Expect(linkFactory.VethDeviceCountCallCount()).To(Equal(0)) err := callback(nil) Expect(linkFactory.VethDeviceCountCallCount()).To(Equal(1)) return err } count, err := sb.VethDeviceCount() Expect(err).NotTo(HaveOccurred()) Expect(count).To(Equal(99)) Expect(sbNamespace.ExecuteCallCount()).To(Equal(1)) }) Context("when namespace execute fails", func() { BeforeEach(func() { sbNamespace.ExecuteReturns(errors.New("meatballs"))