From 2ff8eb4696f315f6f47a7d5b7a7e200a6647ea48 Mon Sep 17 00:00:00 2001
From: Sterling Harper <smharper@mit.edu>
Date: Tue, 7 Aug 2018 17:03:38 -0400
Subject: [PATCH] Add a C-API based restart test

---
 src/state_point.F90           |  3 ++-
 tests/unit_tests/test_capi.py | 28 ++++++++++++++++++++++++++++
 2 files changed, 30 insertions(+), 1 deletion(-)

diff --git a/src/state_point.F90 b/src/state_point.F90
index 4d66a37aa5..3f1d5b3978 100644
--- a/src/state_point.F90
+++ b/src/state_point.F90
@@ -70,6 +70,7 @@ contains
     integer(HID_T) :: cmfd_group, tallies_group, tally_group, meshes_group, &
                       filters_group, filter_group, derivs_group, &
                       deriv_group, runtime_group
+    integer(C_INT) :: ignored_err
     real(C_DOUBLE) :: k_combined(2)
     character(MAX_WORD_LEN), allocatable :: str_array(:)
     character(C_CHAR), pointer :: string(:)
@@ -151,7 +152,7 @@ contains
         call write_dataset(file_id, "k_col_abs", k_col_abs)
         call write_dataset(file_id, "k_col_tra", k_col_tra)
         call write_dataset(file_id, "k_abs_tra", k_abs_tra)
-        err = openmc_get_keff(k_combined)
+        ignored_err = openmc_get_keff(k_combined)
         call write_dataset(file_id, "k_combined", k_combined)
 
         ! Write out CMFD info
diff --git a/tests/unit_tests/test_capi.py b/tests/unit_tests/test_capi.py
index af013cbb5b..288676ff7a 100644
--- a/tests/unit_tests/test_capi.py
+++ b/tests/unit_tests/test_capi.py
@@ -311,3 +311,31 @@ def test_mesh(capi_init):
 
     msf = openmc.capi.MeshSurfaceFilter(mesh)
     assert msf.mesh == mesh
+
+
+def test_restart(pincell_model):
+    # Run for 7 batches then write a statepoint.
+    openmc.capi.init()
+    openmc.capi.simulation_init()
+    for i in range(7):
+        openmc.capi.next_batch()
+    openmc.capi.statepoint_write('restart_test.h5', True)
+
+    # Run 3 more batches and copy the keff.
+    for i in range(3):
+        openmc.capi.next_batch()
+    keff0 = openmc.capi.keff()
+    openmc.capi.simulation_finalize()
+    openmc.capi.finalize()
+
+    # Restart the simulation and run all 10 batches.
+    openmc.capi.init(args=('-r', 'restart_test.h5'))
+    openmc.capi.simulation_init()
+    for i in range(10):
+        openmc.capi.next_batch()
+    keff1 = openmc.capi.keff()
+    openmc.capi.simulation_finalize()
+    openmc.capi.finalize()
+
+    # Compare the keff values.
+    assert keff0 == pytest.approx(keff1)