diff --git a/conftest.py b/conftest.py
new file mode 100644
index 000000000..110fdd479
--- /dev/null
+++ b/conftest.py
@@ -0,0 +1,14 @@
+# This file is here so that when running from the root folder
+# ./sklearn is added to sys.path by pytest.
+# See https://docs.pytest.org/en/latest/pythonpath.html for more details.
+# For example, this allows to build extensions in place and run pytest
+# doc/modules/clustering.rst and use sklearn from the local folder
+# rather than the one from site-packages.
+
+# Set numpy array str/repr to legacy behaviour on numpy > 1.13 to make
+# the doctests pass
+import numpy as np
+try:
+    np.set_printoptions(legacy='1.13')
+except TypeError:
+    pass