add test cases for percentile refine for describe function

Author: ZenithClown

pandas/tests/reductions/test_describe_ndframe.py

@@ -0,0 +1,28 @@
+# -*- encoding: utf-8 -*-
+
+"""
+We test the describe_ndframe function.
+"""
+
+import pytest
+import numpy as np
+
+from pandas.core.methods.describe import _refine_percentiles
+
+def test_refine_percentiles():
+    """
+    Check the performance of the _refine_percentiles when multiple
+    values are passed.
+    """
+
+    # by default 0.25, 0.50, 0.75 is returned
+    # or, when None is passed return behavior is the same
+    assert _refine_percentiles() == np.array([0.25, 0.5, 0.75])
+    assert _refine_percentiles(percentiles = None) == np.array([0.25, 0.5, 0.75])
+
+    # when any value is passed, then the function should return
+    percentiles_ = [0.3, 0.6]
+    assert _refine_percentiles(percentiles_) == np.array(percentiles_)
+
+    # when a blank list is passed, then should return only 0.5
+    assert _refine_percentiles(percentiles = []) == np.array([0.5])