@testset "Propagator" begin

  # Set up
  start = oe_to_xyz([ (μs["Earth"]*(rand(3600*1.5:0.01:3600*4)/(2π))^2)^(1/3),
                       rand(0.01:0.01:0.5),
                       rand(0.01:0.01:0.45π),
                       0.,
                       0.,
                       1. ], μs["Earth"])
  stepsize = rand(100.0:0.01:500.0)

  # Test that Laguerre-Conway is the default propagator
  propped = prop_one([0., 0., 0.], start, 0., 0, 0., 1000., 0.1, μs["Earth"], stepsize)
  @test laguerre_conway(start, μs["Earth"], stepsize) ≈ propped[1]

  # Test that Laguerre-Conway is the default propagator for spacecrafts
  craft = Sc("no_thrust")
  start_mass = craft.mass
  state, craft = prop_one([0., 0., 0.], start, craft, μs["Earth"], stepsize)
  @test laguerre_conway(start, μs["Earth"], stepsize) ≈ state
  @test craft.mass == start_mass

  # Test that mass is reduced properly
  craft = Sc("test")
  start_mass = craft.mass
  state, craft = prop_one([1., 0., 0.], start, craft, μs["Earth"], stepsize)
  @test craft.mass == start_mass - craft.mass_flow_rate*stepsize
  
  # Test that a bad ΔV throws an error
  # craft = Sc("test")
  # start_mass = craft.mass
  # @test_throws ErrorException prop_one([1.5, 0., 0.], start, craft, μs["Earth"], stepsize)

  # Test that a full propagation doesn't take too long


end