diff --git a/Dockerfile b/Dockerfile
index 0209f2a..8f656a9 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,4 +1,4 @@
-FROM ubuntu
+FROM ubuntu:15.04
 MAINTAINER Jim Rybarski <jim@rybarski.com>
 
 RUN mkdir -p /var/nds2
@@ -15,6 +15,3 @@ COPY . /opt/nd2reader
 WORKDIR /opt/nd2reader
 RUN python setup.py install
 RUN python3 setup.py install
-WORKDIR /var/nd2s
-
-CMD /usr/bin/python3.4
\ No newline at end of file
diff --git a/Makefile b/Makefile
index 89b185e..87b2d38 100644
--- a/Makefile
+++ b/Makefile
@@ -8,3 +8,7 @@ py2shell:
 
 py3shell:
 	docker run --rm -v ~/Documents/nd2s:/var/nd2s -it jimrybarski/nd2reader python3.4
+
+test:	build
+	docker run --rm -it jimrybarski/nd2reader python3.4 /opt/nd2reader/tests.py
+
diff --git a/nd2reader/__init__.py b/nd2reader/__init__.py
index aa0d14f..f3f5d7b 100644
--- a/nd2reader/__init__.py
+++ b/nd2reader/__init__.py
@@ -123,16 +123,6 @@ class Nd2(Nd2Parser):
         """
         return self.metadata[six.b('ImageAttributes')][six.b('SLxImageAttributes')][six.b('uiWidth')]
 
-    def _calculate_field_of_view(self, frame_number):
-        images_per_cycle = len(self.z_levels) * len(self.channels)
-        return int((frame_number - (frame_number % images_per_cycle)) / images_per_cycle) % len(self.fields_of_view)
-
-    def _calculate_channel(self, frame_number):
-        return self._channels[frame_number % len(self.channels)]
-
-    def _calculate_z_level(self, frame_number):
-        return self.z_levels[int(((frame_number - (frame_number % len(self.channels))) / len(self.channels)) % len(self.z_levels))]
-
     def get_image(self, time_index, field_of_view, channel_name, z_level):
         """
         Returns an Image if data exists for the given parameters, otherwise returns None. In general, you should avoid
diff --git a/nd2reader/parser.py b/nd2reader/parser.py
index 34acc24..f5bbda5 100644
--- a/nd2reader/parser.py
+++ b/nd2reader/parser.py
@@ -128,6 +128,16 @@ class Nd2Parser(object):
             self._z_levels = self._parse_dimension_text(r""".*?Z\((\d+)\).*?""")
         return self._z_levels
 
+    def _calculate_field_of_view(self, frame_number):
+        images_per_cycle = len(self.z_levels) * len(self.channels)
+        return int((frame_number - (frame_number % images_per_cycle)) / images_per_cycle) % len(self.fields_of_view)
+
+    def _calculate_channel(self, frame_number):
+        return self._channels[frame_number % len(self.channels)]
+
+    def _calculate_z_level(self, frame_number):
+        return self.z_levels[int(((frame_number - (frame_number % len(self.channels))) / len(self.channels)) % len(self.z_levels))]
+
     @property
     def _file_handle(self):
         if self._fh is None:
diff --git a/tests/__init__.py b/tests/__init__.py
index e69de29..531c513 100644
--- a/tests/__init__.py
+++ b/tests/__init__.py
@@ -0,0 +1,19 @@
+from nd2reader.parser import Nd2Parser
+import unittest
+
+
+class MockNd2Parser(object):
+    def __init__(self, channels, fields_of_view, z_levels):
+        self.channels = channels
+        self.fields_of_view = fields_of_view
+        self.z_levels = z_levels
+
+
+class TestNd2Parser(unittest.TestCase):
+    def test_calculate_field_of_view_simple(self):
+        """ With a single field of view, the field of view should always be the same number (0). """
+        nd2 = MockNd2Parser([''], [0], [0])
+        for frame_number in range(1000):
+            result = Nd2Parser._calculate_field_of_view(nd2, frame_number)
+            self.assertEqual(result, 0)
+