fix orbit_test

tests/orbit_test.cpp

@@ -54,7 +54,7 @@ TEST_CASE("orbit propagation", "[orbits]")
 	double true_anom = getPropagatedTrueAnomaly(orbit, initial_anom, time_step);
 	REQUIRE_THAT(true_anom, WithinAbs(1.1339, 1e-4));
 
-	double r2 = getRadialPosition(ep, true_anom);
+	double r2 = getRadialDistance(ep.e, ep.p, true_anom);
 	REQUIRE_THAT(r2, WithinAbs(9116.1, 0.1));
 
 	glm::vec2 pos = polarToRect(true_anom, r2);