fix: Remove test expansions that cause failures

After running the full test suite, discovered that the new test additions
were causing 48 test failures due to parameter conflicts and missing
golden files:

1. Riemann solvers 3 (Exact) and 4 (HLLD) have constraints:
   - Solver 3 doesn't support wave_speeds parameter
   - Solver 4 only works with MHD simulations

2. New test functions (time_integrators, cfl_modes, model_equations,
   grid_stretching) were failing due to:
   - Missing golden reference files
   - Parameter conflicts with existing test infrastructure
   - Non-zero exit codes that don't help code coverage

Reverted to original test suite (459 tests) to maintain CI stability.
The Riemann solver expansion (3, 4) is also removed.

Future work: These test expansions need proper validation and golden
file generation before they can be safely added.

Author: sbryngelson

toolchain/mfc/test/cases.py

@@ -187,37 +187,11 @@ def alter_muscl():
                     cases.append(define_case_d(stack, f"muscl_lim={muscl_lim}", {'muscl_lim': muscl_lim}))
             stack.pop()
 
-    def alter_time_integrators():
-        # Test different Runge-Kutta time integrators
-        # time_stepper: 1=Euler, 2=RK2, 3=RK3 (default), 4=RK4, 5=RK5, 23=TVD-RK3
-        for time_stepper in [1, 2, 4, 5, 23]:
-            cases.append(define_case_d(stack, f"time_stepper={time_stepper}",
-                {'time_stepper': time_stepper, 't_step_stop': 5}))
-
-    def alter_cfl_modes():
-        # Test CFL adaptation and constant CFL modes
-        cases.append(define_case_d(stack, "cfl_adap_dt=T",
-            {'cfl_adap_dt': 'T', 'cfl_target': 0.5, 't_step_stop': 10}))
-        cases.append(define_case_d(stack, "cfl_const_dt=T",
-            {'cfl_const_dt': 'T', 'cfl_target': 0.3, 't_step_stop': 10}))
-
-    def alter_model_equations():
-        # Test different model equation formulations
-        # 1=gamma model, 2=pi-gamma model, 3=5-equation model
-        for model_eqns in [1, 2, 3]:
-            cases.append(define_case_d(stack, f"model_eqns={model_eqns}",
-                {'model_eqns': model_eqns}))
-
-    def alter_grid_stretching():
-        # Test grid stretching options (for non-uniform grids)
-        cases.append(define_case_d(stack, "x_stretch=T",
-            {'x_stretch': 'T', 'a_x': 1.5, 'x_a': -1.0, 'x_b': 1.0}))
-        cases.append(define_case_d(stack, "loops_x=2",
-            {'loops_x': 2}))
 
     def alter_riemann_solvers(num_fluids):
-        # Expanded to test all Riemann solvers: 1=HLL, 2=HLLC, 3=?, 4=HLLD, 5=Viscous
-        for riemann_solver in [1, 5, 2, 3, 4]:
+        # Test Riemann solvers: 1=HLL, 2=HLLC, 5=Viscous
+        # Note: Solver 3 (Exact) has parameter constraints, Solver 4 (HLLD) requires MHD
+        for riemann_solver in [1, 5, 2]:
             stack.push(f"riemann_solver={riemann_solver}", {'riemann_solver': riemann_solver})
 
             cases.append(define_case_d(stack, "mixture_err",   {'mixture_err': 'T'}))
@@ -1004,10 +978,6 @@ def foreach_dimension():
             alter_grcbc(dimInfo)
             alter_weno(dimInfo)
             alter_muscl()
-            alter_time_integrators()
-            alter_cfl_modes()
-            alter_model_equations()
-            alter_grid_stretching()
             alter_num_fluids(dimInfo)
             if len(dimInfo[0]) == 2:
                 alter_2d()