t.Run("test timeout after server removed", func(t *testing.T) {
		f := fsm{
			Topology: description.Topology{
				Kind:                     description.ReplicaSetWithPrimary,
				SessionTimeoutMinutesPtr: int64ToPtr(1),
				Servers: []description.Server{
					{
						Kind:                     description.RSPrimary,
						SessionTimeoutMinutesPtr: int64ToPtr(2),
						Addr:                     "host1:27017",
						Members: []address.Address{
							"host1:27017",
							"host2:27017",
						},
					},
					{
						Kind:                     description.RSSecondary,
						SessionTimeoutMinutesPtr: int64ToPtr(1),
						Addr:                     "host2:27017",
						Members: []address.Address{
							"host1:27017",
							"host2:27017",
						},
					},
				},
			},
		}

		// Apply a new server description that removes `host2` from the FSM.
		f.apply(description.Server{
			Kind:                     description.RSPrimary,
			SessionTimeoutMinutesPtr: int64ToPtr(2),
			Addr:                     "host1:27017",
			Members: []address.Address{
				"host1:27017",
			},
		})

		expect := []description.Server{
			{
				Kind:                     description.RSPrimary,
				SessionTimeoutMinutesPtr: int64ToPtr(2),
				Addr:                     "host1:27017",
				Members: []address.Address{
					"host1:27017",
				},
			},
		}

		assert.Equal(t, expect, f.Servers)

		// Check that the SessionTimeoutMinutesPtr has been updated to the new minimum (2).
		assert.NotNil(t, f.SessionTimeoutMinutesPtr)
		assert.Equal(t, *f.SessionTimeoutMinutesPtr, int64(2)) // Fails
	})