From 775c784ba0a0c1019f24a0e69d182d2c33549728 Mon Sep 17 00:00:00 2001
From: DanRyanIrish <ryand5@tcd.ie>
Date: Wed, 28 Mar 2018 17:44:08 -0400
Subject: [PATCH] Set matplotlib backend for Travis.

---
 .travis.yml                   | 8 ++++++++
 ndcube/mixins/plotting.py     | 2 +-
 ndcube/tests/test_plotting.py | 2 +-
 3 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/.travis.yml b/.travis.yml
index 284cfe99c..1806834a2 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -54,6 +54,9 @@ matrix:
 
     include:
 
+        # Add a matplotlib backend for generating plots in tests.
+        - env: MPLBACKEND='Agg'
+
         # Do a basic test.
         - os: linux
           stage: Initial tests
@@ -99,6 +102,11 @@ install:
     - git clone git://github.com/astropy/ci-helpers.git
     - source ci-helpers/travis/setup_conda.sh
 
+before_script:
+    - "export DISPLAY=:99.0"
+    - "sh -e /etc/init.d/xvfb start"
+    - sleep 3 # give xvfb some time to start
+
 script:
    - $MAIN_CMD $SETUP_CMD
 
diff --git a/ndcube/mixins/plotting.py b/ndcube/mixins/plotting.py
index ee72f9fe1..2470eed1f 100644
--- a/ndcube/mixins/plotting.py
+++ b/ndcube/mixins/plotting.py
@@ -150,7 +150,7 @@ def _plot_3D_cube(self, plot_axis_indices=None, axes_units=None,
         if plot_axis_indices is None:
             plot_axis_indices = [-1, -2]
         if axes_units is None:
-           axes_units = [None, None]
+            axes_units = [None, None]
         i = ImageAnimatorWCS(self.data, wcs=self.wcs, image_axes=plot_axis_indices,
                              unit_x_axis=axes_units[0], unit_y_axis=axes_units[1],
                              axis_ranges=axes_coordinates, **kwargs)
diff --git a/ndcube/tests/test_plotting.py b/ndcube/tests/test_plotting.py
index bdee098eb..1d44888d4 100644
--- a/ndcube/tests/test_plotting.py
+++ b/ndcube/tests/test_plotting.py
@@ -87,7 +87,7 @@ def test_cube_plot_1D(test_input, test_kwargs, expected_values):
     output_ylim = output.axes.get_ylim()
     assert output_ylim[0] <= expected_ylim[0]
     assert output_ylim[1] >= expected_ylim[1]
-    
+
 
 @pytest.mark.parametrize("test_input, test_kwargs, expected_values", [
     (cube[0], {},