diff --git a/tests/simulator/test_python_concurrent.py b/tests/simulator/test_python_concurrent.py
index 89e0d9fa4..91be34ef4 100644
--- a/tests/simulator/test_python_concurrent.py
+++ b/tests/simulator/test_python_concurrent.py
@@ -4,54 +4,80 @@
 """
 
 import os
+import time
 import unittest
-import multiprocessing
+from multiprocessing import cpu_count
 
 from tests.simulator.test_validation import SimulatorValidation
+from tests.simulator.test_diagnostics import DiagnosticsTest  # mpirun -n 1/2/3/4
 
-from tests.simulator.initialize.test_fields_init_1d import InitializationTest as InitField1d
-from tests.simulator.initialize.test_particles_init_1d import InitializationTest as InitParticles1d
+import tests.simulator.initialize.test_fields_init_1d as test_fields_init_1d
+# from tests.simulator.initialize.test_fields_init_1d import (
+#     InitializationTest as InitField1d,
+# )
+# from tests.simulator.initialize.test_particles_init_1d import (
+#     InitializationTest as InitParticles1d,
+# )
+# from tests.simulator.advance.test_fields_advance_1d import AdvanceTest as AdvanceField1d
+# from tests.simulator.advance.test_particles_advance_1d import (
+#     AdvanceTest as AdvanceParticles1d,
+# )
+# from tests.simulator.initialize.test_fields_init_2d import (
+#     InitializationTest as InitField2d,
+# )
+# from tests.simulator.initialize.test_particles_init_2d import (
+#     InitializationTest as InitParticles2d,
+# )
+# from tests.simulator.advance.test_fields_advance_2d import AdvanceTest as AdvanceField2d
+# from tests.simulator.advance.test_particles_advance_2d import (
+#     AdvanceTest as AdvanceParticles2d,
+# )
 
-from tests.simulator.advance.test_fields_advance_1d import AdvanceTest as AdvanceField1d
-from tests.simulator.advance.test_particles_advance_1d import AdvanceTest as AdvanceParticles1d
+from phlop.testing.parallel_processor import load_test_cases_in, process
 
-from tests.simulator.initialize.test_fields_init_2d import InitializationTest as InitField2d
-from tests.simulator.initialize.test_particles_init_2d import InitializationTest as InitParticles2d
+N_CORES = int(os.environ["N_CORES"]) if "N_CORES" in os.environ else cpu_count()
+PRINT = int(os.environ["PRINT"]) if "PRINT" in os.environ else 0
+MPI_RUN = os.environ.get("MPI_RUN", None)
+MPI_RUN_EXTRA = os.environ.get("MPI_RUN_EXTRA", "")
 
-from tests.simulator.advance.test_fields_advance_2d import AdvanceTest as AdvanceField2d
-from tests.simulator.advance.test_particles_advance_2d import AdvanceTest as AdvanceParticles2d
+def test_cmd(clazz, test_id, mpi_run):
+    return f"mpirun {MPI_RUN_EXTRA} -n {mpi_run} python3 -m {clazz.__module__} {clazz.__name__}.{test_id}"
 
 
-N_CORES = int(os.environ["N_CORES"]) if "N_CORES" in os.environ else multiprocessing.cpu_count()
-MPI_RUN = int(os.environ["MPI_RUN"]) if "MPI_RUN" in os.environ else 1
-PRINT   = int(os.environ["PRINT"]) if "PRINT" in os.environ else 0
 
-def test_cmd(clazz, test_id):
-    return f"mpirun -n {MPI_RUN} python3 -m {clazz.__module__} {clazz.__name__}.{test_id}"
+test_classes_to_run = [
+    SimulatorValidation,
+    DiagnosticsTest,
+    test_fields_init_1d.InitializationTest,
+    # InitField1d,
+    # InitParticles1d,
+    # AdvanceField1d,
+    # AdvanceParticles1d,
+    # InitField2d,
+    # InitParticles2d,
+    # AdvanceField2d,
+    # AdvanceParticles2d,
+]
 
-if __name__ == "__main__":
 
-    test_classes_to_run = [
-      SimulatorValidation,
-      InitField1d,
-      InitParticles1d,
-      AdvanceField1d,
-      AdvanceParticles1d,
-      InitField2d,
-      InitParticles2d,
-      AdvanceField2d,
-      AdvanceParticles2d
-    ]
-
-    tests = []
-    loader = unittest.TestLoader()
-    for test_class in test_classes_to_run:
-        for suite in loader.loadTestsFromTestCase(test_class):
-            tests += [test_cmd(type(suite), suite._testMethodName)]
-
-    from tools.python3 import run_mp
-    if PRINT:
-        for test in tests:
-            print(test)
+def load_test_cases(classes, cores):
+    return load_test_cases_in(classes, cores, test_cmd_fn=test_cmd)
+
+def build_batches():
+    batches = []
+    if not MPI_RUN:
+        batches += [load_test_cases(test_classes_to_run, 1)]
+        batches += [load_test_cases(test_classes_to_run, 2)]
+        batches += [load_test_cases([DiagnosticsTest], 3)]
+        batches += [load_test_cases([DiagnosticsTest], 4)]
     else:
-        run_mp(tests, N_CORES, check=True)
+        batches += [load_test_cases(test_classes_to_run, int(MPI_RUN))]
+    return batches
+
+
+def main():
+    process(build_batches())
+
+
+if __name__ == "__main__":
+    main()