Context("when attaching disk to cloud fails", func() { BeforeEach(func() { fakeCloud.AttachDiskErr = errors.New("fake-attach-error") }) It("returns an error", func() { err := vm.AttachDisk(disk) Expect(err).To(HaveOccurred()) Expect(err.Error()).To(ContainSubstring("fake-attach-error")) }) }) Context("when mounting disk fails", func() { BeforeEach(func() { fakeAgentClient.SetMountDiskBehavior(errors.New("fake-mount-error")) }) It("returns an error", func() { err := vm.AttachDisk(disk) Expect(err).To(HaveOccurred()) Expect(err.Error()).To(ContainSubstring("fake-mount-error")) }) }) }) Describe("DetachDisk", func() { var disk *fakebidisk.FakeDisk BeforeEach(func() { disk = fakebidisk.NewFakeDisk("fake-disk-cid")