Improve Sphere regression tests

Ensure filename consistency etc across tests

Migrated eta import test but still need to fix an error with this test.

Author: dav-og

tests/regression/sphere/compare.py

@@ -15,7 +15,7 @@
 from pathlib import Path
 
 # Import the comparison template
-sys.path.append(os.path.join(os.path.dirname(__file__), '..'))
+sys.path.append(os.path.join(os.path.dirname(__file__), '../utilities'))
 from compare_template import run_comparison
 
 if __name__ == '__main__':
@@ -38,10 +38,12 @@
     # Ensure the plots directory exists
     plots_dir.mkdir(parents=True, exist_ok=True)
     print(f"Plot will be saved to: {plots_dir}")
-    print(f"Plot filename: {plots_dir}/Sphere Decay Test_comparison.png")
 
     # Sphere-specific configuration
     test_name = "Sphere Decay Test"
+    # Convert test_name to lowercase with underscores for filename
+    safe_test_name = test_name.lower().replace(' ', '_').replace('-', '_')
+    print(f"Plot filename: {plots_dir}/{safe_test_name}_comparison.png")
     y_label = "Heave (m)"
     executable_patterns = ["sphere_decay_test", "sphere_decay"]
     pass_criteria = (1e-4, 0.02)  # (L2 threshold, L-infinity threshold)

tests/regression/sphere/demo_sphere_decay.cpp

@@ -136,7 +136,7 @@ int main(int argc, char* argv[]) {
     ensure_directory_exists(results_dir);
 
     if (profilingOn) {
-        std::ofstream profilingFile(results_dir / "sphere_decay_duration.txt");
+        std::ofstream profilingFile(results_dir / "CHRONO_SPHERE_DECAY_HEAVE_DURATION.txt");
         if (profilingFile.is_open()) {
             profilingFile << duration << " ms\n";
             profilingFile.close();
@@ -146,7 +146,7 @@ int main(int argc, char* argv[]) {
     }
 
     if (saveDataOn) {
-        std::ofstream outputFile(results_dir / "sphere_decay.txt");
+        std::ofstream outputFile(results_dir / "CHRONO_SPHERE_DECAY_HEAVE.txt");
         if (outputFile.is_open()) {
             outputFile << std::left << std::setw(10) << "Time (s)" << std::right << std::setw(12)
                        << "Heave (m)"