[TEST] Pandas optional

.travis.yml

@@ -15,14 +15,13 @@ env:
   matrix:
     - LINTING=1
     - DOCTEST=1
-    - JOBLIB=1
+    - JOBLIB=1 PANDAS=1
 
 matrix:
   include:
   - python: 3.6
     env:
-      - COVERAGE=1
-      - JOBLIB=1
+      - COVERAGE=1 JOBLIB=1 PANDAS=1
   - python: 3.7
     dist: xenial
     sudo: required
@@ -42,6 +41,8 @@ before_install:
     fi
   - if [ "${JOBLIB}" == "1" ]; then
         pip install joblib;
+  - if [ "${PANDAS}" == "1" ]; then
+        pip install pandas;
     fi
 
 install:

pyls/examples/datasets.py

@@ -10,10 +10,15 @@
 import urllib
 
 import numpy as np
-import pandas as pd
 
 from ..structures import PLSInputs
 
+try:
+    import pandas as pd
+    pandas_avail = True
+except ImportError:
+    pandas_avail = False
+
 with open(resource_filename('pyls', 'examples/datasets.json'), 'r') as src:
     _DATASETS = json.load(src)
 
@@ -132,7 +137,10 @@ def load_dataset(name, data_dir=None, verbose=1, return_reference=False):
         if isinstance(value, str) and key in PLSInputs.allowed:
             fname = os.path.join(data_dir, name, value)
             if fname.endswith('.csv'):
-                value = pd.read_csv(fname, index_col=0)
+                if pandas_avail:
+                    value = pd.read_csv(fname, index_col=0)
+                else:
+                    value = np.loadtxt(fname, skiprows=1, delimiter=',')[:, 1:]
             elif fname.endswith('.txt'):
                 value = np.loadtxt(fname)
             elif fname.endswith('.npy'):