Fix tests on big-endian systems (#3125)

* Fix tests on big-endian systems

* PEP 8

xarray/tests/test_dataarray.py

@@ -3140,7 +3140,9 @@ def test_to_and_from_dict(self):
         expected_no_data = expected.copy()
         del expected_no_data['data']
         del expected_no_data['coords']['x']['data']
-        expected_no_data['coords']['x'].update({'dtype': '<U1', 'shape': (2,)})
+        endiantype = '<U1' if sys.byteorder == 'little' else '>U1'
+        expected_no_data['coords']['x'].update({'dtype': endiantype,
+                                                'shape': (2,)})
         expected_no_data.update({'dtype': 'float64', 'shape': (2, 3)})
         actual_no_data = array.to_dict(data=False)
         assert expected_no_data == actual_no_data

xarray/tests/test_dataset.py

@@ -3460,7 +3460,8 @@ def test_to_and_from_dict(self):
         del expected_no_data['coords']['t']['data']
         del expected_no_data['data_vars']['a']['data']
         del expected_no_data['data_vars']['b']['data']
-        expected_no_data['coords']['t'].update({'dtype': '<U1',
+        endiantype = '<U1' if sys.byteorder == 'little' else '>U1'
+        expected_no_data['coords']['t'].update({'dtype': endiantype,
                                                 'shape': (10,)})
         expected_no_data['data_vars']['a'].update({'dtype': 'float64',
                                                    'shape': (10,)})

xarray/tests/test_formatting.py

@@ -1,5 +1,6 @@
 # -*- coding: utf-8 -*-
 from textwrap import dedent
+import sys
 
 import numpy as np
 import pandas as pd
@@ -204,6 +205,7 @@ def test_diff_array_repr(self):
                     'label': ('x', np.array([1, 2], dtype='int64'))},
             attrs={'units': 'kg'})
 
+        byteorder = '<' if sys.byteorder == 'little' else '>'
         expected = dedent("""\
         Left and right DataArray objects are not identical
         Differing dimensions:
@@ -215,8 +217,8 @@ def test_diff_array_repr(self):
         R
             array([1, 2], dtype=int64)
         Differing coordinates:
-        L * x        (x) <U1 'a' 'b'
-        R * x        (x) <U1 'a' 'c'
+        L * x        (x) %cU1 'a' 'b'
+        R * x        (x) %cU1 'a' 'c'
         Coordinates only on the left object:
           * y        (y) int64 1 2 3
         Coordinates only on the right object:
@@ -225,7 +227,7 @@ def test_diff_array_repr(self):
         L   units: m
         R   units: kg
         Attributes only on the left object:
-            description: desc""")
+            description: desc""" % (byteorder, byteorder))
 
         actual = formatting.diff_array_repr(da_a, da_b, 'identical')
         try:
@@ -277,13 +279,14 @@ def test_diff_dataset_repr(self):
             attrs={'units': 'kg'}
         )
 
+        byteorder = '<' if sys.byteorder == 'little' else '>'
         expected = dedent("""\
         Left and right Dataset objects are not identical
         Differing dimensions:
             (x: 2, y: 3) != (x: 2)
         Differing coordinates:
-        L * x        (x) <U1 'a' 'b'
-        R * x        (x) <U1 'a' 'c'
+        L * x        (x) %cU1 'a' 'b'
+        R * x        (x) %cU1 'a' 'c'
             source: 0
         Coordinates only on the left object:
           * y        (y) int64 1 2 3
@@ -298,7 +301,7 @@ def test_diff_dataset_repr(self):
         L   units: m
         R   units: kg
         Attributes only on the left object:
-            description: desc""")
+            description: desc""" % (byteorder, byteorder))
 
         actual = formatting.diff_dataset_repr(ds_a, ds_b, 'identical')
         assert actual == expected