added test for particle restart

tests/test_particle_restart/geometry.xml

@@ -0,0 +1,12 @@
+<?xml version="1.0"?>
+<geometry>
+
+  <!-- Nested Cylinders with Tracking Error -->
+  <surface id="1" type="z-cylinder" coeffs="0.0 0.0 10.0"                       />
+  <surface id="2" type="z-cylinder" coeffs="0.0 0.0 20.0" boundary="reflective" />
+  <surface id="3" type="z-plane"    coeffs="5.0"          boundary="reflective" />
+  <surface id="4" type="z-plane"    coeffs="-5.0"         boundary="reflective" />
+  <cell id="1" material="1" surfaces="-1 3 -4" />
+  <cell id="2" material="1" surfaces="1 -2"/>
+    
+</geometry>

tests/test_particle_restart/materials.xml

@@ -0,0 +1,9 @@
+<?xml version="1.0"?>
+<materials>
+
+  <material id="1">
+    <density value="4.5" units="g/cc" />
+    <nuclide name="U-235" xs="70c" ao="1.0" />
+  </material>
+
+</materials>

tests/test_particle_restart/settings.xml

@@ -0,0 +1,16 @@
+<?xml version="1.0"?>
+<settings>
+
+  <eigenvalue>
+    <batches>10</batches>
+    <inactive>5</inactive>
+    <particles>1000</particles>
+  </eigenvalue>
+
+  <source>
+    <space type="box">
+      <parameters>-20 -20 -5  20  20  5</parameters>
+    </space>
+  </source>
+
+</settings>

tests/test_particle_restart/test_particle_restart.py

@@ -0,0 +1,31 @@
+#!/usr/bin/env python
+
+import os
+from subprocess import Popen, STDOUT, PIPE
+
+pwd = os.path.dirname(__file__)
+
+def setup(): 
+    os.putenv('PWD', pwd)
+    os.chdir(pwd)
+
+def test_run():
+    proc = Popen([pwd + '/../../src/openmc'], stderr=STDOUT, stdout=PIPE)
+    returncode = proc.wait()
+    print(proc.communicate()[0])
+    assert returncode == 0
+
+def test_run_restart():
+    proc = Popen([pwd + '/../../src/openmc'], stderr=STDOUT, stdout=PIPE)
+    returncode = proc.wait()
+    print(proc.communicate()[0])
+    assert returncode == 0
+
+def test_created_restart():
+    assert os.path.exists(pwd + '/particle_0.binary')
+
+def teardown():
+    output = [pwd + '/particle_0.binary']
+    for f in output:
+        if os.path.exists(f):
+            os.remove(f)