diff --git a/tests/__init__.py b/tests/__init__.py
index d107e38..d5e8b88 100644
--- a/tests/__init__.py
+++ b/tests/__init__.py
@@ -11,25 +11,28 @@
 
 from .test_bzip2mrcfile import Bzip2MrcFileTest
 from .test_command_line import CommandLineTest
+from .test_dtypes import DtypesTest
 from .test_future_mrcfile import FutureMrcFileTest
 from .test_gzipmrcfile import GzipMrcFileTest
-from .test_load_functions import LoadFunctionTest
-from .test_mrcobject import MrcObjectTest
-from .test_mrcinterpreter import MrcInterpreterTest
+from .test_load_functions import LoadFunctionTest, LoadFunctionTestWithPathlib
 from .test_mrcfile import MrcFileTest
+from .test_mrcinterpreter import MrcInterpreterTest
 from .test_mrcmemmap import MrcMemmapTest
+from .test_mrcobject import MrcObjectTest
 from .test_utils import UtilsTest
 from .test_validation import ValidationTest
 
 test_classes = [
     Bzip2MrcFileTest,
     CommandLineTest,
+    DtypesTest,
     FutureMrcFileTest,
     GzipMrcFileTest,
     LoadFunctionTest,
-    MrcObjectTest,
-    MrcInterpreterTest,
+    LoadFunctionTestWithPathlib,
     MrcFileTest,
+    MrcInterpreterTest,
+    MrcObjectTest,
     MrcMemmapTest,
     UtilsTest,
     ValidationTest
diff --git a/tests/test_bzip2mrcfile.py b/tests/test_bzip2mrcfile.py
index c8dc5b9..5462fe1 100644
--- a/tests/test_bzip2mrcfile.py
+++ b/tests/test_bzip2mrcfile.py
@@ -12,11 +12,11 @@
 import os
 import unittest
 
-from .test_mrcfile import MrcFileTest
+from . import test_mrcfile
 from mrcfile.bzip2mrcfile import Bzip2MrcFile
 
 
-class Bzip2MrcFileTest(MrcFileTest):
+class Bzip2MrcFileTest(test_mrcfile.MrcFileTest):
     
     """Unit tests for bzip2 MRC file I/O.
     
diff --git a/tests/test_gzipmrcfile.py b/tests/test_gzipmrcfile.py
index 506bc9a..770a8e5 100644
--- a/tests/test_gzipmrcfile.py
+++ b/tests/test_gzipmrcfile.py
@@ -12,11 +12,11 @@
 import os
 import unittest
 
-from .test_mrcfile import MrcFileTest
+from . import test_mrcfile
 from mrcfile.gzipmrcfile import GzipMrcFile
 
 
-class GzipMrcFileTest(MrcFileTest):
+class GzipMrcFileTest(test_mrcfile.MrcFileTest):
     
     """Unit tests for gzipped MRC file I/O.
     
diff --git a/tests/test_load_functions.py b/tests/test_load_functions.py
index 765a772..7ed8de1 100644
--- a/tests/test_load_functions.py
+++ b/tests/test_load_functions.py
@@ -103,10 +103,12 @@ def test_new_empty_file_with_open_function(self):
                                  .format(self.temp_mrc_name))
 
     def test_error_overwriting_file_with_open_function(self):
-        assert not os.path.exists(self.temp_mrc_name)
-        open(self.temp_mrc_name, 'w+').close()
-        assert os.path.exists(self.temp_mrc_name)
-        with self.assertRaisesRegex(ValueError, "call 'mrcfile\.new\(\)'"):
+        # Convert name to str to avoid TypeErrors in Python 2.7 with pathlib
+        temp_mrc_name_str = str(self.temp_mrc_name)
+        assert not os.path.exists(temp_mrc_name_str)
+        open(temp_mrc_name_str, 'w+').close()
+        assert os.path.exists(temp_mrc_name_str)
+        with self.assertRaisesRegex(ValueError, r"call 'mrcfile\.new\(\)'"):
             mrcfile.open(self.temp_mrc_name, mode='w+')
 
     def test_header_only_opening(self):
diff --git a/tests/test_mrcfile.py b/tests/test_mrcfile.py
index 7a2a845..0e326bd 100644
--- a/tests/test_mrcfile.py
+++ b/tests/test_mrcfile.py
@@ -22,8 +22,7 @@
 except ImportError:
     from numpy import ComplexWarning
 
-from . import helpers
-from .test_mrcobject import MrcObjectTest
+from . import helpers, test_mrcobject
 from mrcfile.mrcfile import MrcFile
 from mrcfile.mrcobject import (IMAGE_STACK_SPACEGROUP, VOLUME_SPACEGROUP,
                                VOLUME_STACK_SPACEGROUP)
@@ -58,7 +57,7 @@
 #     return tests
 
 
-class MrcFileTest(MrcObjectTest):
+class MrcFileTest(test_mrcobject.MrcObjectTest):
 
     """Unit tests for MRC file I/O.
 
diff --git a/tests/test_mrcinterpreter.py b/tests/test_mrcinterpreter.py
index 1fdff3e..1f73f6e 100644
--- a/tests/test_mrcinterpreter.py
+++ b/tests/test_mrcinterpreter.py
@@ -15,12 +15,12 @@
 
 import numpy as np
 
-from .test_mrcobject import MrcObjectTest
+from . import test_mrcobject
 from mrcfile.constants import MAP_ID_OFFSET_BYTES
 from mrcfile.mrcinterpreter import MrcInterpreter
 
 
-class MrcInterpreterTest(MrcObjectTest):
+class MrcInterpreterTest(test_mrcobject.MrcObjectTest):
     
     """Unit tests for MrcInterpreter class.
     
diff --git a/tests/test_mrcmemmap.py b/tests/test_mrcmemmap.py
index 237503e..9a1692d 100644
--- a/tests/test_mrcmemmap.py
+++ b/tests/test_mrcmemmap.py
@@ -14,11 +14,11 @@
 
 import numpy as np
 
-from .test_mrcfile import MrcFileTest
+from . import test_mrcfile
 from mrcfile.mrcmemmap import MrcMemmap
 
 
-class MrcMemmapTest(MrcFileTest):
+class MrcMemmapTest(test_mrcfile.MrcFileTest):
     
     """Unit tests for MRC file I/O with memory-mapped files.