TST: fix tests not passing

tests/fixtures/flight/flight_fixtures.py

@@ -164,21 +164,6 @@ def flight_calisto_hybrid_modded(calisto_hybrid_modded, example_plain_env):
     )
 
 
-def flight_calisto_robust_solid_eom(calisto_robust, example_spaceport_env):
-    """Similar to flight_calisto_robust, but with the equations of motion set to
-    "solid_propulsion".
-    """
-    return Flight(
-        environment=example_spaceport_env,
-        rocket=calisto_robust,
-        rail_length=5.2,
-        inclination=85,
-        heading=0,
-        terminate_on_apogee=False,
-        equations_of_motion="solid_propulsion",
-    )
-
-
 @pytest.fixture
 def flight_calisto_custom_wind(calisto_robust, example_spaceport_env):
     """A rocketpy.Flight object of the Calisto rocket. This uses the calisto