@testset "Phase" begin

  println("Testing NLP solver")

  # We'll start by testing the mission_guess -> vector function
  vec = Vector(test_mg)
  @test typeof(vec) == Vector{Float64}

  # Now we go in the other direction
  flybys = [ p.planet for p in test_mg.phases ]
  guess = Mission_Guess(vec, test_mg.sc, test_mg.start_mass, flybys)
  @test typeof(guess) == Mission_Guess
  @test guess.sc == test_mg.sc
  @test guess.start_mass == test_mg.start_mass
  @test guess.launch_date == test_mg.launch_date
  @test guess.launch_v∞ == test_mg.launch_v∞
  @test guess.converged == test_mg.converged
  for i in 1:length(guess.phases)
    @test guess.phases[i].planet == test_mg.phases[i].planet
    @test guess.phases[i].v∞_in == test_mg.phases[i].v∞_in
    @test guess.phases[i].v∞_out == test_mg.phases[i].v∞_out
    @test guess.phases[i].tof == test_mg.phases[i].tof
    @test guess.phases[i].thrust_profile == test_mg.phases[i].thrust_profile
  end

  # Now we test an example run of the basic "inner function"
  leave, arrive = DateTime(1992,11,19), DateTime(1993,4,1)
  earth_state = state(Earth, leave)
  venus_state = state(Venus, arrive)
  v∞_out, v∞_in, tof = Thesis.lamberts(Earth, Venus, leave, arrive)
  phase = Phase(Venus, v∞_in, v∞_in, tof, zeros(20,3))
  guess = Mission_Guess(bepi, 12_000., leave, v∞_out, [phase])
  g = solve_mission(guess)
  println(g)

end