add Codacy grade

.codacy.yml

@@ -0,0 +1,6 @@
+exclude_paths:
+  - 'docs/**'
+  - 'versioneer.py'
+  - '**/_version.py'
+  - '**/__init__.py'
+  - '**/tests/**'

README.rst

@@ -14,6 +14,14 @@ gMeterPy
         :target: https://codecov.io/gh/opengrav/gmeterpy
         :alt: Test coverage status
 
+.. image:: https://img.shields.io/codacy/grade/2c08b4ce758f484e8ac0aafddbd6ada7.svg
+        :target: https://www.codacy.com/app/ioshchepkov/gmeterpy
+        :alt: Codacy grade
+
+.. image:: https://img.shields.io/pypi/pyversions/gmeterpy.svg
+        :alt: Compatible Python versions
+        :target: https://pypi.python.org/pypi/gmeterpy
+
 .. image:: https://readthedocs.org/projects/gmeterpy/badge/?version=latest
         :target: https://gmeterpy.readthedocs.io/en/latest/?badge=latest
         :alt: Documentation Status

gmeterpy/corrections/tests/test_polar_motion.py

@@ -36,13 +36,13 @@ def test_get_polar_motion():
 
     # Bulletin A
     time = Time.now()
-    xp, yp, status = pm.get_polar_motion(time, return_status=True)
+    _, _, status = pm.get_polar_motion(time, return_status=True)
     assert status[0] == 'IERS_A'
 
     # Out of range
     delta = TimeDelta(400, format='jd')
     time += delta
-    xp, yp, status = pm.get_polar_motion(time, return_status=True)
+    _, _, status = pm.get_polar_motion(time, return_status=True)
     assert status[0] == 'OUT_OF_RANGE'