TST: Use absolute path for datapath (pandas-dev#21647)

Author: elmq0022

pandas/conftest.py

@@ -153,8 +153,10 @@ def datapath(request):
     ValueError
         If the path doesn't exist and the --strict-data-files option is set.
     """
+    BASE_PATH = os.path.join(os.path.dirname(__file__), 'tests')
+
     def deco(*args):
-        path = os.path.join('pandas', 'tests', *args)
+        path = os.path.join(BASE_PATH, *args)
         if not os.path.exists(path):
             if request.config.getoption("--strict-data-files"):
                 msg = "Could not find file {} and --strict-data-files is set."

pandas/tests/util/test_testing.py

@@ -852,5 +852,10 @@ def test_datapath_missing(datapath, request):
         datapath('not_a_file')
 
     result = datapath('data', 'iris.csv')
-    expected = os.path.join('pandas', 'tests', 'data', 'iris.csv')
+    expected = os.path.join(
+        os.path.dirname(os.path.dirname(__file__)),
+        'data',
+        'iris.csv'
+    )
+
     assert result == expected