unittest for the InterPro retriever

tests/test_ipro.py

+import unittest
+from dbxref.retrieve import ipro
+
+
+class TestIPro(unittest.TestCase):
+
+    # Test if ipro retriever gives any output
+    def test_output(self):
+        documents = ipro.retrieve([{'db': 'InterPro', 'id': 'IPR000003'}], basics=True, hierarchy=True, wikipedia=True,
+                                  literature=True, cross_references=True, overlaps=True)
+        self.assertTrue(documents)
+
+
+if __name__ == '__main__':
+    unittest.main()