use old_tests/ while refactoring tests

old_tests/test_energy.toml

@@ -0,0 +1,27 @@
+# Test Configuration: Sun + Earth (circular orbit)
+# Earth at 1 AU with circular orbit
+# Expected orbital period: ~365 days
+
+[[bodies]]
+name = "Sun"
+mass = 1.989e30
+radius = 6.96e8
+parent_index = -1
+color = { r = 1.0, g = 1.0, b = 0.0 }
+orbit = {
+    semi_major_axis = 0.0,
+    eccentricity = 0.0,
+    true_anomaly = 0.0
+}
+
+[[bodies]]
+name = "Earth"
+mass = 5.972e24
+radius = 6.371e6
+parent_index = 0
+color = { r = 0.0, g = 0.5, b = 1.0 }
+orbit = {
+    semi_major_axis = 1.496e11,
+    eccentricity = 0.0,
+    true_anomaly = 0.0
+}

old_tests/test_orbital_period.cpp

@@ -0,0 +1,102 @@
+#include <catch2/catch_test_macros.hpp>
+#include "../src/physics.h"
+#include "../src/simulation.h"
+#include "../src/config_loader.h"
+#include "../src/test_utilities.h"
+#include <cmath>
+
+TEST_CASE("Orbital period - Earth (RK4)", "[period][rk4]") {
+    const double TIME_STEP = 60.0;
+    const double EXPECTED_PERIOD_DAYS = 365.0;
+    const double SECONDS_PER_DAY = 86400.0;
+    const double MAX_SIMULATION_DAYS = 400.0;
+
+    SimulationState* sim = create_simulation(10, 0, 0, TIME_STEP);
+
+    REQUIRE(load_system_config(sim, "tests/test_orbital_period.toml"));
+
+    OrbitTracker* tracker = create_orbit_tracker(1);
+
+    double max_time = MAX_SIMULATION_DAYS * SECONDS_PER_DAY;
+    while (sim->time < max_time && !tracker->orbit_completed) {
+        update_simulation(sim);
+        update_orbit_tracker(tracker, &sim->bodies[1], &sim->bodies[0], sim->time);
+    }
+
+    REQUIRE(tracker->orbit_completed);
+
+    double measured_period_days = tracker->time_at_completion / SECONDS_PER_DAY;
+    double period_error_days = fabs(measured_period_days - EXPECTED_PERIOD_DAYS);
+
+    INFO("Expected period: " << EXPECTED_PERIOD_DAYS << " days");
+    INFO("Measured period: " << measured_period_days << " days");
+    INFO("Error: " << period_error_days << " days");
+
+    REQUIRE(period_error_days < 5.0);
+
+    destroy_orbit_tracker(tracker);
+    destroy_simulation(sim);
+}
+
+TEST_CASE("Orbital period - Mars (RK4)", "[period][rk4]") {
+    const double TIME_STEP = 60.0;
+    const double EXPECTED_PERIOD_DAYS = 687.0;
+    const double SECONDS_PER_DAY = 86400.0;
+    const double MAX_SIMULATION_DAYS = 750.0;
+
+    SimulationState* sim = create_simulation(10, 0, 0, TIME_STEP);
+
+    REQUIRE(load_system_config(sim, "tests/test_orbital_period.toml"));
+
+    OrbitTracker* tracker = create_orbit_tracker(2);
+
+    double max_time = MAX_SIMULATION_DAYS * SECONDS_PER_DAY;
+    while (sim->time < max_time && !tracker->orbit_completed) {
+        update_simulation(sim);
+        update_orbit_tracker(tracker, &sim->bodies[2], &sim->bodies[0], sim->time);
+    }
+
+    REQUIRE(tracker->orbit_completed);
+
+    double measured_period_days = tracker->time_at_completion / SECONDS_PER_DAY;
+    double period_error_days = fabs(measured_period_days - EXPECTED_PERIOD_DAYS);
+
+    INFO("Expected period: " << EXPECTED_PERIOD_DAYS << " days");
+    INFO("Measured period: " << measured_period_days << " days");
+    INFO("Error: " << period_error_days << " days");
+
+    REQUIRE(period_error_days < 25.0);
+
+    destroy_orbit_tracker(tracker);
+    destroy_simulation(sim);
+}
+
+TEST_CASE("Orbit direction - prograde for zero inclination", "[direction]") {
+    const double TIME_STEP = 60.0;
+    const double TEST_DURATION_DAYS = 1.0;
+    const double SECONDS_PER_DAY = 86400.0;
+    const int STEPS = (int)(TEST_DURATION_DAYS * SECONDS_PER_DAY / TIME_STEP);
+
+    SimulationState* sim = create_simulation(2, 0, 0, TIME_STEP);
+    REQUIRE(load_system_config(sim, "tests/test_energy.toml"));
+
+    CelestialBody* sun = &sim->bodies[0];
+    CelestialBody* earth = &sim->bodies[1];
+
+    Vec3 initial_rel_pos = vec3_sub(earth->global_position, sun->global_position);
+    double theta_start = atan2(initial_rel_pos.y, initial_rel_pos.x);
+
+    for (int i = 0; i < STEPS; i++) {
+        update_simulation(sim);
+    }
+
+    Vec3 final_rel_pos = vec3_sub(earth->global_position, sun->global_position);
+    double theta_final = atan2(final_rel_pos.y, final_rel_pos.x);
+
+    INFO("Initial angle: " << theta_start << " rad");
+    INFO("Final angle: " << theta_final << " rad");
+
+    REQUIRE(theta_final > theta_start);
+
+    destroy_simulation(sim);
+}

old_tests/test_orbital_period.toml

@@ -0,0 +1,39 @@
+# Test Configuration: Sun + Earth + Mars (circular orbits)
+# Earth at 1 AU, Mars at 1.5 AU with circular orbits
+# Expected orbital periods: Earth ~365 days, Mars ~687 days
+
+[[bodies]]
+name = "Sun"
+mass = 1.989e30
+radius = 6.96e8
+parent_index = -1
+color = { r = 1.0, g = 1.0, b = 0.0 }
+orbit = {
+    semi_major_axis = 0.0,
+    eccentricity = 0.0,
+    true_anomaly = 0.0
+}
+
+[[bodies]]
+name = "Earth"
+mass = 5.972e24
+radius = 6.371e6
+parent_index = 0
+color = { r = 0.0, g = 0.5, b = 1.0 }
+orbit = {
+    semi_major_axis = 1.496e11,
+    eccentricity = 0.0,
+    true_anomaly = 0.0
+}
+
+[[bodies]]
+name = "Mars"
+mass = 6.39e23
+radius = 3.3895e6
+parent_index = 0
+color = { r = 0.8, g = 0.3, b = 0.1 }
+orbit = {
+    semi_major_axis = 2.244e11,
+    eccentricity = 0.0,
+    true_anomaly = 0.0
+}

old_tests/test_true_anomaly_roundtrip.cpp

@@ -0,0 +1,133 @@
+#include <catch2/catch_test_macros.hpp>
+#include <catch2/matchers/catch_matchers_floating_point.hpp>
+#include "../src/physics.h"
+#include "../src/orbital_mechanics.h"
+#include <cmath>
+
+TEST_CASE("True anomaly round-trip conversion at periapsis", "[orbital_elements][true_anomaly]") {
+    double parent_mass = 5.972e24;
+
+    OrbitalElements elements = {0};
+    elements.semi_major_axis = 7000e3;
+    elements.eccentricity = 0.3;
+    elements.true_anomaly = 0.0;
+    elements.inclination = 0.0;
+    elements.longitude_of_ascending_node = 0.0;
+    elements.argument_of_periapsis = 0.0;
+
+    Vec3 pos, vel;
+    orbital_elements_to_cartesian(elements, parent_mass, &pos, &vel);
+    OrbitalElements reconstructed = cartesian_to_orbital_elements(pos, vel, parent_mass);
+
+    INFO("Original true_anomaly: " << elements.true_anomaly);
+    INFO("Reconstructed true_anomaly: " << reconstructed.true_anomaly);
+
+    REQUIRE_THAT(reconstructed.true_anomaly,
+                 Catch::Matchers::WithinAbs(elements.true_anomaly, 0.01));
+}
+
+TEST_CASE("True anomaly round-trip conversion at apoapsis", "[orbital_elements][true_anomaly]") {
+    double parent_mass = 5.972e24;
+
+    OrbitalElements elements = {0};
+    elements.semi_major_axis = 7000e3;
+    elements.eccentricity = 0.3;
+    elements.true_anomaly = M_PI;
+    elements.inclination = 0.0;
+    elements.longitude_of_ascending_node = 0.0;
+    elements.argument_of_periapsis = 0.0;
+
+    Vec3 pos, vel;
+    orbital_elements_to_cartesian(elements, parent_mass, &pos, &vel);
+    OrbitalElements reconstructed = cartesian_to_orbital_elements(pos, vel, parent_mass);
+
+    INFO("Original true_anomaly: " << elements.true_anomaly);
+    INFO("Reconstructed true_anomaly: " << reconstructed.true_anomaly);
+
+    REQUIRE_THAT(reconstructed.true_anomaly,
+                 Catch::Matchers::WithinAbs(elements.true_anomaly, 0.01));
+}
+
+TEST_CASE("True anomaly round-trip conversion at 90 degrees", "[orbital_elements][true_anomaly]") {
+    double parent_mass = 5.972e24;
+
+    OrbitalElements elements = {0};
+    elements.semi_major_axis = 7000e3;
+    elements.eccentricity = 0.3;
+    elements.true_anomaly = M_PI / 2.0;
+    elements.inclination = 0.0;
+    elements.longitude_of_ascending_node = 0.0;
+    elements.argument_of_periapsis = 0.0;
+
+    Vec3 pos, vel;
+    orbital_elements_to_cartesian(elements, parent_mass, &pos, &vel);
+    OrbitalElements reconstructed = cartesian_to_orbital_elements(pos, vel, parent_mass);
+
+    INFO("Original true_anomaly: " << elements.true_anomaly);
+    INFO("Reconstructed true_anomaly: " << reconstructed.true_anomaly);
+
+    REQUIRE_THAT(reconstructed.true_anomaly,
+                 Catch::Matchers::WithinAbs(elements.true_anomaly, 0.01));
+}
+
+TEST_CASE("True anomaly round-trip conversion at 270 degrees", "[orbital_elements][true_anomaly]") {
+    double parent_mass = 5.972e24;
+
+    OrbitalElements elements = {0};
+    elements.semi_major_axis = 7000e3;
+    elements.eccentricity = 0.3;
+    elements.true_anomaly = 3.0 * M_PI / 2.0;
+    elements.inclination = 0.0;
+    elements.longitude_of_ascending_node = 0.0;
+    elements.argument_of_periapsis = 0.0;
+
+    Vec3 pos, vel;
+    orbital_elements_to_cartesian(elements, parent_mass, &pos, &vel);
+    OrbitalElements reconstructed = cartesian_to_orbital_elements(pos, vel, parent_mass);
+
+    INFO("Original true_anomaly: " << elements.true_anomaly);
+    INFO("Reconstructed true_anomaly: " << reconstructed.true_anomaly);
+
+    REQUIRE_THAT(reconstructed.true_anomaly,
+                 Catch::Matchers::WithinAbs(elements.true_anomaly, 0.01));
+}
+
+TEST_CASE("Radius at periapsis matches expected value", "[orbital_elements][sanity]") {
+    double parent_mass = 5.972e24;
+
+    OrbitalElements peri = {0};
+    peri.semi_major_axis = 7000e3;
+    peri.eccentricity = 0.3;
+    peri.true_anomaly = 0.0;
+
+    Vec3 pos, vel;
+    orbital_elements_to_cartesian(peri, parent_mass, &pos, &vel);
+    double r_peri = vec3_magnitude(pos);
+    double expected_peri = peri.semi_major_axis * (1.0 - peri.eccentricity);
+
+    INFO("At true_anomaly=0:");
+    INFO("  Calculated radius: " << r_peri);
+    INFO("  Expected: " << expected_peri);
+
+    REQUIRE_THAT(r_peri, Catch::Matchers::WithinAbs(expected_peri, 1.0));
+}
+
+TEST_CASE("Radius at apoapsis matches expected value", "[orbital_elements][sanity]") {
+    double parent_mass = 5.972e24;
+
+    OrbitalElements apo = {0};
+    apo.semi_major_axis = 7000e3;
+    apo.eccentricity = 0.3;
+    apo.true_anomaly = M_PI;
+
+    Vec3 pos, vel;
+    orbital_elements_to_cartesian(apo, parent_mass, &pos, &vel);
+    double r_apo = vec3_magnitude(pos);
+    double expected_apo = apo.semi_major_axis * (1.0 + apo.eccentricity);
+
+    INFO("At true_anomaly=pi:");
+    INFO("  Calculated radius: " << r_apo);
+    INFO("  Expected: " << expected_apo);
+
+    REQUIRE_THAT(r_apo, Catch::Matchers::WithinAbs(expected_apo, 1.0));
+}

tests/informational/Makefile

@@ -1,73 +0,0 @@
-# Makefile for Informational Tests
-# These tests are not part of the main test suite
-# They are for diagnostic and informational purposes only
-
-BUILD_DIR = ../../build
-SRC_DIR = ../../src
-
-# Compiler flags
-CFLAGS = -Wall -Wextra -g -ggdb3 -std=c++14
-INCLUDES = -I$(SRC_DIR) \
-           -isystem../../ext/tomlc17/src \
-           -isystem../../ext/raylib/src \
-           -isystem../../ext/raygui/src \
-           -isystem../../ext/raygui/styles
-
-# Source files (from main project that informational tests depend on)
-CORE_OBJECTS = $(BUILD_DIR)/test_utilities.o \
-             $(BUILD_DIR)/physics.o \
-             $(BUILD_DIR)/orbital_mechanics.o \
-             $(BUILD_DIR)/simulation.o \
-             $(BUILD_DIR)/config_loader.o \
-             $(BUILD_DIR)/config_validator.o \
-             $(BUILD_DIR)/maneuver.o \
-             $(BUILD_DIR)/spacecraft.o \
-             $(BUILD_DIR)/tomlc17.o
-
-# Informational test sources
-INFO_TESTS = test_time_step_stability.cpp
-INFO_BINS = $(patsubst %.cpp,%,$(INFO_TESTS))
-
-# Default target - build all informational tests
-all: $(INFO_BINS)
-	@echo "All informational tests built successfully"
-	@echo ""
-	@echo "To run tests:"
-	@echo "  ./test_time_step_stability"
-	@echo ""
-	@echo "To run specific test case:"
-	@echo "  ./test_time_step_stability '[timestep][stability]'"
-
-# Build individual test binaries
-$(INFO_BINS): $(patsubst %.cpp,%.o,$(INFO_TESTS)) $(CORE_OBJECTS)
-	g++ $(patsubst %.cpp,%.o,$<) $(CORE_OBJECTS) -o $@ -lCatch2Main -lCatch2 -lm
-	@echo "Built $@"
-
-# Build test object files
-test_time_step_stability.o: test_time_step_stability.cpp
-	g++ $(CFLAGS) $(INCLUDES) -c $< -o $@
-
-# Build core objects if they don't exist
-$(BUILD_DIR)/%.o:
-	$(MAKE) -C ../../ build/$*.o
-
-# Clean built files in informational directory
-clean:
-	rm -f $(INFO_BINS) *.o
-
-# Clean all (including core build - use with caution!)
-clean-all:
-	$(MAKE) -C ../../ clean
-	rm -f $(INFO_BINS) *.o
-
-# Run the time step stability test (must run from project root)
-run-timestep: test_time_step_stability
-	@echo "Note: Tests must be run from project root directory:"
-	@echo "  From project root: ./tests/informational/$@"
-
-# Run with verbose output to see binary search progress
-run-timestep-verbose: test_time_step_stability
-	@echo "Note: Tests must be run from project root directory:"
-	@echo "  From project root: ./tests/informational/$@ -s \"[timestep][stability]\""
-
-.PHONY: all clean clean-all run-timestep run-timestep-verbose

tests/informational/README.md

@@ -1,72 +0,0 @@
-# Informational Tests
-
-This directory contains tests that are not part of the standard test suite. These tests are provided for informational purposes only and should be run separately.
-
-## Purpose
-
-Informational tests are designed to:
-- Explore simulation boundaries and limits
-- Provide diagnostic information about the simulation
-- Test extreme or edge cases that don't fit into normal test suites
-- Help understand system behavior under various conditions
-
-## Running Informational Tests
-
-Informational tests are **not** run by `make test`. To build and run them:
-
-```bash
-cd tests/informational
-make
-./time_step_test
-```
-
-## Current Tests
-
-### `test_time_step_stability.cpp`
-
-Determines the maximum stable time step for the RK4 integration across different orbital regimes.
-
-**Test Bodies:**
-- **Mercury Orbiter** (MESSENGER-like): 200 km altitude, ~12 hour period
-- **Io** (Jupiter's moon): 421,700 km orbit, ~1.77 day period
-- **Moon** (Earth's moon): 384,400 km orbit, ~27.3 day period
-
-**Stability Criteria:**
-- Energy drift < 1% over 100 orbits
-- Distance drift < 5%
-- No SOI transitions (body doesn't change parent)
-
-**Configuration:** Uses `test_time_step_stability.toml`
-
-**Usage:**
-```bash
-# From project root directory:
-./tests/informational/test_time_step_stability
-
-# Or using the Makefile:
-cd tests/informational
-make run-timestep
-
-# Run specific test case
-./tests/informational/test_time_step_stability '[timestep][stability]'
-
-# Run with verbose output to see binary search progress
-./tests/informational/test_time_step_stability -s "[timestep][stability]"
-```
-
-**Note:** Tests must be run from the project root directory because config file paths are relative to the root.
-
-**Expected Output:**
-The test performs a binary search to find the maximum stable time step, printing progress for each dt value tested. Results show the minimum stable dt across all tested bodies with recommendations.
-
-## Adding New Informational Tests
-
-1. Create a new `.cpp` file in this directory
-2. Add corresponding `.toml` config file if needed
-3. Add a target in the `Makefile`:
-   ```makefile
-   your_test_name: your_test_name.o
-   	g++ $(BUILD_DIR)/*.o -o $@ -lCatch2Main -lCatch2 -lm
-   ```
-4. Update this README with test description
-5. Follow the naming convention: `test_<purpose>.cpp` and `test_<purpose>.toml`

tests/informational/test_time_step_stability.cpp

@@ -1,296 +0,0 @@
-#include <catch2/catch_test_macros.hpp>
-#include "../../src/physics.h"
-#include "../../src/simulation.h"
-#include "../../src/config_loader.h"
-#include "../../src/test_utilities.h"
-#include <cmath>
-#include <cstdio>
-
-struct TestBody {
-    const char* name;
-    int body_index;
-    int parent_index;
-    double expected_period_days;
-};
-
-struct StabilityResult {
-    const char* name;
-    double max_stable_dt;
-    double period_days;
-};
-
-const double SECONDS_PER_DAY = 86400.0;
-const double MIN_DT = 30.0;
-const double MAX_DT = 600.0;
-const double ENERGY_TOLERANCE = 1.0;
-const int NUM_ORBITS = 100;
-
-double calculate_orbital_period(CelestialBody* body, CelestialBody* parent) {
-    Vec3 relative_pos = vec3_sub(body->global_position, parent->global_position);
-    double r = vec3_magnitude(relative_pos);
-    Vec3 relative_vel = vec3_sub(body->global_velocity, parent->global_velocity);
-    double v = vec3_magnitude(relative_vel);
-
-    double specific_energy = (v * v) / 2.0 - G * parent->mass / r;
-    double semi_major_axis = -G * parent->mass / (2.0 * specific_energy);
-    double period_seconds = 2.0 * M_PI * sqrt(pow(semi_major_axis, 3.0) / (G * parent->mass));
-
-    return period_seconds;
-}
-
-bool is_dt_stable(SimulationState* sim, const TestBody& test_body, double dt, int num_orbits) {
-    SimulationState* test_sim = create_simulation(sim->max_bodies, sim->max_craft, sim->max_maneuvers, dt);
-
-    REQUIRE(load_system_config(test_sim, "tests/informational/test_time_step_stability.toml"));
-
-    int body_index = test_body.body_index;
-    int parent_index = test_body.parent_index;
-
-    double initial_energy = calculate_system_total_energy(test_sim);
-
-    Vec3 initial_pos_relative = vec3_sub(
-        test_sim->bodies[body_index].global_position,
-        test_sim->bodies[parent_index].global_position
-    );
-    double initial_distance = vec3_magnitude(initial_pos_relative);
-
-    double period = calculate_orbital_period(&test_sim->bodies[body_index], &test_sim->bodies[parent_index]);
-    double max_time = period * num_orbits;
-
-    bool completed = true;
-    while (test_sim->time < max_time) {
-        update_simulation(test_sim);
-
-        if (test_sim->bodies[body_index].parent_index != parent_index) {
-            completed = false;
-            break;
-        }
-    }
-
-    double final_energy = calculate_system_total_energy(test_sim);
-    double energy_drift_percent = fabs((final_energy - initial_energy) / initial_energy) * 100.0;
-
-    Vec3 final_pos_relative = vec3_sub(
-        test_sim->bodies[body_index].global_position,
-        test_sim->bodies[parent_index].global_position
-    );
-    double final_distance = vec3_magnitude(final_pos_relative);
-    double distance_drift_percent = fabs((final_distance - initial_distance) / initial_distance) * 100.0;
-
-    bool stable = completed && (energy_drift_percent < ENERGY_TOLERANCE) && (distance_drift_percent < 5.0);
-
-    destroy_simulation(test_sim);
-
-    return stable;
-}
-
-double find_max_stable_dt(SimulationState* sim, const TestBody& test_body) {
-    double low = MIN_DT;
-    double high = MAX_DT;
-    double max_stable = low;
-
-    printf("Testing %s (period ~%.2f days):\n", test_body.name, test_body.expected_period_days);
-
-    for (int iter = 0; iter < 10; iter++) {
-        double mid = (low + high) / 2.0;
-        bool stable = is_dt_stable(sim, test_body, mid, NUM_ORBITS);
-
-        if (stable) {
-            max_stable = mid;
-            low = mid;
-            printf("  dt=%.0fs: STABLE\n", mid);
-        } else {
-            high = mid;
-            printf("  dt=%.0fs: UNSTABLE\n", mid);
-        }
-
-        if (high - low < 5.0) break;
-    }
-
-    printf("  Maximum stable dt: %.0f seconds\n\n", max_stable);
-    return max_stable;
-}
-
-void print_summary(const StabilityResult* results, int num_results, double min_stable_dt, double default_dt) {
-    printf("\n");
-    printf("===============================================================================\n");
-    printf("                    TIME STEP STABILITY TEST RESULTS\n");
-    printf("===============================================================================\n\n");
-
-    printf("STABILITY CRITERIA:\n");
-    printf("  - Energy drift < %.1f%% over %d orbits\n", ENERGY_TOLERANCE, NUM_ORBITS);
-    printf("  - Distance drift < 5.0%%\n");
-    printf("  - No SOI transitions (parent changes)\n\n");
-
-    printf("PER-BODY RESULTS:\n");
-    printf("+----------------------+----------------+------------------+----------------+\n");
-    printf("| Body                 | Period (days)  | Max Stable dt (s) | Stability Status |\n");
-    printf("+----------------------+----------------+------------------+----------------+\n");
-
-    for (int i = 0; i < num_results; i++) {
-        const StabilityResult& r = results[i];
-        double ratio = default_dt / r.max_stable_dt;
-        const char* status = ratio < 0.5 ? "Very Stable" : ratio < 0.8 ? "Stable" : "Limited Margin";
-        printf("| %-20s | %14.2f | %16.0f | %-14s |\n", r.name, r.period_days, r.max_stable_dt, status);
-    }
-
-    printf("+----------------------+----------------+------------------+----------------+\n\n");
-
-    printf("OVERALL ANALYSIS:\n");
-    printf("  Minimum stable time step: %.0f seconds\n", min_stable_dt);
-    printf("  Recommended safe dt:     %.0f seconds (0.7x safety margin)\n", min_stable_dt * 0.7);
-    printf("  Current default dt:        %.0f seconds\n", default_dt);
-    printf("  Current dt stability:     %.0fx\n", default_dt / min_stable_dt);
-    printf("\n");
-
-    if (default_dt < min_stable_dt * 0.7) {
-        printf("STATUS: Current time step (60s) is VERY STABLE with good margin.\n");
-        printf("        Can be increased significantly if needed.\n\n");
-    } else if (default_dt < min_stable_dt) {
-        printf("STATUS: Current time step (60s) is STABLE with adequate margin.\n");
-        printf("        Moderate increases possible.\n\n");
-    } else {
-        printf("STATUS: Current time step (60s) is near stability limit.\n");
-        printf("        Consider reducing for safety.\n\n");
-    }
-
-    printf("RECOMMENDATIONS:\n");
-    printf("  - For MESSENGER-like close orbits: Keep dt <= %.0f seconds\n", min_stable_dt);
-    printf("  - For planetary missions: Current dt=60s is excellent\n");
-    printf("  - For Moon-scale orbits: Could use dt=120s+ safely\n");
-    printf("\n");
-    printf("===============================================================================\n\n");
-}
-
-TEST_CASE("Time step stability - Mercury orbiter (MESSENGER-like)", "[timestep][stability]") {
-    const double BASE_DT = 60.0;
-    SimulationState* sim = create_simulation(10, 0, 0, BASE_DT);
-
-    TestBody mercury_orbiter = {"Mercury_Orbiter", 1, 0, 0.5};
-    double max_dt = find_max_stable_dt(sim, mercury_orbiter);
-
-    INFO("Mercury orbiter maximum stable dt: " << max_dt << " seconds");
-
-    REQUIRE(max_dt >= MIN_DT);
-
-    destroy_simulation(sim);
-}
-
-TEST_CASE("Time step stability - Io (Jupiter's moon)", "[timestep][stability]") {
-    const double BASE_DT = 60.0;
-    SimulationState* sim = create_simulation(10, 0, 0, BASE_DT);
-
-    TestBody io = {"Io", 3, 2, 1.77};
-    double max_dt = find_max_stable_dt(sim, io);
-
-    INFO("Io maximum stable dt: " << max_dt << " seconds");
-
-    REQUIRE(max_dt >= MIN_DT);
-
-    destroy_simulation(sim);
-}
-
-TEST_CASE("Time step stability - Moon (Earth's moon)", "[timestep][stability]") {
-    const double BASE_DT = 60.0;
-    SimulationState* sim = create_simulation(10, 0, 0, BASE_DT);
-
-    TestBody moon = {"Moon", 5, 4, 27.3};
-    double max_dt = find_max_stable_dt(sim, moon);
-
-    INFO("Moon maximum stable dt: " << max_dt << " seconds");
-
-    REQUIRE(max_dt >= MIN_DT);
-
-    destroy_simulation(sim);
-}
-
-TEST_CASE("Find minimum stable time step across all bodies", "[timestep][stability]") {
-    const double BASE_DT = 60.0;
-    SimulationState* sim = create_simulation(10, 0, 0, BASE_DT);
-
-    TestBody bodies[] = {
-        {"Mercury_Orbiter", 1, 0, 0.5},
-        {"Io", 3, 2, 1.77},
-        {"Moon", 5, 4, 27.3}
-    };
-
-    StabilityResult results[3];
-    double max_dt = MAX_DT;
-
-    printf("\n=== Finding minimum stable dt across all bodies ===\n\n");
-
-    for (int i = 0; i < 3; i++) {
-        results[i].name = bodies[i].name;
-        results[i].period_days = bodies[i].expected_period_days;
-        results[i].max_stable_dt = find_max_stable_dt(sim, bodies[i]);
-        if (results[i].max_stable_dt < max_dt) {
-            max_dt = results[i].max_stable_dt;
-        }
-    }
-
-    printf("\n=== RESULTS ===\n");
-    printf("Minimum stable time step: %.0f seconds\n", max_dt);
-    printf("Recommended safe time step: %.0f seconds (%.0fx safety margin)\n", max_dt * 0.7, 1.0/0.7);
-
-    INFO("Minimum stable dt: " << max_dt << " seconds");
-
-    print_summary(results, 3, max_dt, BASE_DT);
-
-    REQUIRE(max_dt >= MIN_DT);
-
-    destroy_simulation(sim);
-}
-
-TEST_CASE("Verify current default dt (60s) stability", "[timestep][stability]") {
-    const double DT = 60.0;
-    const int NUM_ORBITS = 10;
-
-    SimulationState* sim = create_simulation(10, 0, 0, DT);
-    REQUIRE(load_system_config(sim, "tests/informational/test_time_step_stability.toml"));
-
-    struct BodyTest {
-        int body_index;
-        int parent_index;
-        const char* name;
-    };
-
-    BodyTest tests[] = {
-        {1, 0, "Mercury_Orbiter"},
-        {3, 2, "Io"},
-        {5, 4, "Moon"}
-    };
-
-    for (int t = 0; t < 3; t++) {
-        int body_index = tests[t].body_index;
-        int parent_index = tests[t].parent_index;
-        const char* name = tests[t].name;
-
-        double period = calculate_orbital_period(&sim->bodies[body_index], &sim->bodies[parent_index]);
-        double max_time = period * NUM_ORBITS;
-
-        double initial_energy = calculate_system_total_energy(sim);
-
-        INFO("Testing " << name << " with dt=" << DT << "s for " << NUM_ORBITS << " orbits");
-
-        bool completed = true;
-        while (sim->time < max_time) {
-            update_simulation(sim);
-
-            if (sim->bodies[body_index].parent_index != parent_index) {
-                completed = false;
-                break;
-            }
-        }
-
-        double final_energy = calculate_system_total_energy(sim);
-        double energy_drift_percent = fabs((final_energy - initial_energy) / initial_energy) * 100.0;
-
-        INFO(name << " completed: " << (completed ? "yes" : "no"));
-        INFO(name << " energy drift: " << energy_drift_percent << "%");
-
-        REQUIRE(completed);
-        REQUIRE(energy_drift_percent < ENERGY_TOLERANCE);
-    }
-
-    destroy_simulation(sim);
-}

tests/informational/test_time_step_stability.toml

@@ -1,80 +0,0 @@
-# Time Step Stability Test Configuration
-# Contains bodies with different orbital periods for testing RK4 stability
-
-[[bodies]]
-name = "Mercury"
-mass = 3.285e23
-radius = 2.439e6
-parent_index = -1
-color = { r = 0.7, g = 0.7, b = 0.7 }
-orbit = {
-    semi_major_axis = 0.0,
-    eccentricity = 0.0,
-    true_anomaly = 0.0
-}
-
-# Low Mercury orbiter at 200 km altitude (MESSENGER-like)
-# Period ~12 hours - most restrictive case
-[[bodies]]
-name = "Mercury_Orbiter"
-mass = 1000.0
-radius = 1.0
-parent_index = 0
-color = { r = 1.0, g = 0.0, b = 1.0 }
-orbit = {
-    semi_major_axis = 2.639e6,
-    eccentricity = 0.0,
-    true_anomaly = 0.0
-}
-
-[[bodies]]
-name = "Jupiter"
-mass = 1.898e27
-radius = 6.9911e7
-parent_index = -1
-color = { r = 0.9, g = 0.7, b = 0.5 }
-orbit = {
-    semi_major_axis = 0.0,
-    eccentricity = 0.0,
-    true_anomaly = 0.0
-}
-
-# Io - Jupiter's moon
-# Period ~1.77 days
-[[bodies]]
-name = "Io"
-mass = 8.93e22
-radius = 1.822e6
-parent_index = 2
-color = { r = 0.9, g = 0.9, b = 0.3 }
-orbit = {
-    semi_major_axis = 4.217e8,
-    eccentricity = 0.0,
-    true_anomaly = 0.0
-}
-
-[[bodies]]
-name = "Earth"
-mass = 5.972e24
-radius = 6.371e6
-parent_index = -1
-color = { r = 0.0, g = 0.5, b = 1.0 }
-orbit = {
-    semi_major_axis = 0.0,
-    eccentricity = 0.0,
-    true_anomaly = 0.0
-}
-
-# Moon - Earth's moon
-# Period ~27.3 days
-[[bodies]]
-name = "Moon"
-mass = 7.342e22
-radius = 1.737e6
-parent_index = 4
-color = { r = 0.7, g = 0.7, b = 0.7 }
-orbit = {
-    semi_major_axis = 3.844e8,
-    eccentricity = 0.0,
-    true_anomaly = 0.0
-}