From dacf650eaf74ce6b138c0225cfcc83d4c622a39d Mon Sep 17 00:00:00 2001
From: Paul Romano <paul.k.romano@gmail.com>
Date: Thu, 8 Feb 2018 14:32:28 -0600
Subject: [PATCH] Fix bug with clearing k_generation and entropy

---
 src/simulation.F90            |  2 ++
 tests/__init__.py             | 15 +++++++++++++++
 tests/unit_tests/test_capi.py | 33 ++++++++++++++++++++-------------
 3 files changed, 37 insertions(+), 13 deletions(-)

diff --git a/src/simulation.F90 b/src/simulation.F90
index 424c55e9bd..0204aaf796 100644
--- a/src/simulation.F90
+++ b/src/simulation.F90
@@ -454,6 +454,8 @@ contains
 
     ! Reset global variables
     current_batch = 0
+    call k_generation % clear()
+    call entropy % clear()
     need_depletion_rx = .false.
 
     ! Set flag indicating initialization is done
diff --git a/tests/__init__.py b/tests/__init__.py
index e69de29bb2..5c21cd9380 100644
--- a/tests/__init__.py
+++ b/tests/__init__.py
@@ -0,0 +1,15 @@
+from contextlib import contextmanager
+import os
+import tempfile
+
+
+@contextmanager
+def cdtemp():
+    """Context manager to change to/return from a tmpdir."""
+    with tempfile.TemporaryDirectory() as tmpdir:
+        cwd = os.getcwd()
+        try:
+            os.chdir(tmpdir)
+            yield
+        finally:
+            os.chdir(cwd)
diff --git a/tests/unit_tests/test_capi.py b/tests/unit_tests/test_capi.py
index e1e87e27b3..618f54e4f9 100644
--- a/tests/unit_tests/test_capi.py
+++ b/tests/unit_tests/test_capi.py
@@ -1,5 +1,3 @@
-#!/usr/bin/env python
-
 from collections import Mapping
 import os
 
@@ -8,12 +6,15 @@ import pytest
 import openmc
 import openmc.capi
 
+from tests import cdtemp
+
 
 @pytest.fixture(scope='module')
 def pincell_model():
     """Set up a model to test with and delete files when done"""
     openmc.reset_auto_ids()
     pincell = openmc.examples.pwr_pin_cell()
+    pincell.settings.verbosity = 1
 
     # Add a tally
     filter1 = openmc.MaterialFilter(pincell.materials)
@@ -24,17 +25,10 @@ def pincell_model():
     mat_tally.scores = ['total', 'elastic', '(n,gamma)']
     pincell.tallies.append(mat_tally)
 
-    # Write XML files
-    pincell.export_to_xml()
-
-    yield
-
-    # Delete generated files
-    files = ['geometry.xml', 'materials.xml', 'settings.xml', 'tallies.xml',
-             'statepoint.10.h5', 'summary.h5', 'test_sp.h5']
-    for f in files:
-        if os.path.exists(f):
-            os.remove(f)
+    # Write XML files in tmpdir
+    with cdtemp():
+        pincell.export_to_xml()
+        yield
 
 
 @pytest.fixture(scope='module')
@@ -229,6 +223,19 @@ def test_by_batch(capi_run):
     openmc.capi.simulation_finalize()
 
 
+def test_reproduce_keff(capi_init):
+    # Get k-effective after run
+    openmc.capi.hard_reset()
+    openmc.capi.run()
+    keff0 = openmc.capi.keff()
+
+    # Reset, run again, and get k-effective again. they should match
+    openmc.capi.hard_reset()
+    openmc.capi.run()
+    keff1 = openmc.capi.keff()
+    assert keff0 == pytest.approx(keff1)
+
+
 def test_find_cell(capi_init):
     cell, instance = openmc.capi.find_cell((0., 0., 0.))
     assert cell is openmc.capi.cells[1]