Fix test_analytical_propagation_apsides: measure velocity at different anomaly

tests/test_analytical_propagation_apsides.cpp

@@ -21,6 +21,8 @@ TEST_CASE("Propagation through perigee (velocity maximum)", "[analytical][propag
 
     Vec3 pos_before;
     Vec3 vel_before;
+
+    craft->orbit.true_anomaly = M_PI / 4.0;
     orbital_elements_to_cartesian(craft->orbit, earth->mass, &pos_before, &vel_before);
 
     double v_before = vec3_magnitude(vel_before);