diff --git a/swh/indexer/tests/test_ctags.py b/swh/indexer/tests/test_ctags.py
index ae45338..21939d7 100644
--- a/swh/indexer/tests/test_ctags.py
+++ b/swh/indexer/tests/test_ctags.py
@@ -1,104 +1,153 @@
 # Copyright (C) 2017-2018  The Software Heritage developers
 # See the AUTHORS file at the top-level directory of this distribution
 # License: GNU General Public License version 3, or any later version
 # See top-level LICENSE file for more information
 
 import unittest
 import logging
-from swh.indexer.ctags import CtagsIndexer
+
+from unittest.mock import patch
+from swh.indexer.ctags import (
+    CtagsIndexer, run_ctags
+)
+
 from swh.indexer.tests.test_utils import (
     BasicMockIndexerStorage, MockObjStorage, CommonContentIndexerTest,
     CommonIndexerWithErrorsTest, CommonIndexerNoTool,
     SHA1_TO_CTAGS, NoDiskIndexer
 )
 
 
+class BasicTest(unittest.TestCase):
+    @patch('swh.indexer.ctags.subprocess')
+    def test_run_ctags(self, mock_subprocess):
+        """Computing licenses from a raw content should return results
+
+        """
+        output0 = """
+{"name":"defun","kind":"function","line":1,"language":"scheme"}
+{"name":"name","kind":"symbol","line":5,"language":"else"}"""
+        output1 = """
+{"name":"let","kind":"var","line":10,"language":"something"}"""
+
+        expected_result0 = [
+            {
+                'name': 'defun',
+                'kind': 'function',
+                'line': 1,
+                'lang': 'scheme'
+            },
+            {
+                'name': 'name',
+                'kind': 'symbol',
+                'line': 5,
+                'lang': 'else'
+            }
+        ]
+
+        expected_result1 = [
+            {
+                'name': 'let',
+                'kind': 'var',
+                'line': 10,
+                'lang': 'something'
+            }
+        ]
+        for path, lang, intermediary_result, expected_result in [
+                (b'some/path', 'lisp', output0, expected_result0),
+                (b'some/path/2', 'markdown', output1, expected_result1)
+        ]:
+            mock_subprocess.check_output.return_value = intermediary_result
+            actual_result = list(run_ctags(path, lang=lang))
+            self.assertEqual(actual_result, expected_result)
+
+
 class InjectCtagsIndexer:
     """Override ctags computations.
 
     """
     def compute_ctags(self, path, lang):
         """Inject fake ctags given path (sha1 identifier).
 
         """
         return {
             'lang': lang,
             **SHA1_TO_CTAGS.get(path)
         }
 
 
 class CtagsIndexerTest(NoDiskIndexer, InjectCtagsIndexer, CtagsIndexer):
     """Specific language whose configuration is enough to satisfy the
        indexing tests.
     """
     def prepare(self):
         self.config = {
             'tools': {
                 'name': 'universal-ctags',
                 'version': '~git7859817b',
                 'configuration': {
                     'command_line': '''ctags --fields=+lnz --sort=no '''
                                     ''' --links=no <filepath>''',
                     'max_content_size': 1000,
                 },
             },
             'languages': {
                 'python': 'python',
                 'haskell': 'haskell',
                 'bar': 'bar',
             }
         }
         self.idx_storage = BasicMockIndexerStorage()
         self.log = logging.getLogger('swh.indexer')
         self.objstorage = MockObjStorage()
         self.tool_config = self.config['tools']['configuration']
         self.max_content_size = self.tool_config['max_content_size']
         self.tools = self.register_tools(self.config['tools'])
         self.tool = self.tools[0]
         self.language_map = self.config['languages']
 
 
 class TestCtagsIndexer(CommonContentIndexerTest, unittest.TestCase):
     """Ctags indexer test scenarios:
 
     - Known sha1s in the input list have their data indexed
     - Unknown sha1 in the input list are not indexed
 
     """
     def setUp(self):
         self.indexer = CtagsIndexerTest()
 
         # Prepare test input
         self.id0 = '01c9379dfc33803963d07c1ccc748d3fe4c96bb5'
         self.id1 = 'd4c647f0fc257591cc9ba1722484229780d1c607'
         self.id2 = '688a5ef812c53907562fe379d4b3851e69c7cb15'
 
         tool_id = self.indexer.tool['id']
         self.expected_results = {
             self.id0: {
                 'id': self.id0,
                 'indexer_configuration_id': tool_id,
                 'ctags': SHA1_TO_CTAGS[self.id0],
             },
             self.id1: {
                 'id': self.id1,
                 'indexer_configuration_id': tool_id,
                 'ctags': SHA1_TO_CTAGS[self.id1],
             },
             self.id2: {
                 'id': self.id2,
                 'indexer_configuration_id': tool_id,
                 'ctags': SHA1_TO_CTAGS[self.id2],
             }
         }
 
 
 class CtagsIndexerUnknownToolTestStorage(
         CommonIndexerNoTool, CtagsIndexerTest):
     """Fossology license indexer with wrong configuration"""
 
 
 class TestCtagsIndexersErrors(
         CommonIndexerWithErrorsTest, unittest.TestCase):
     """Test the indexer raise the right errors when wrongly initialized"""
     Indexer = CtagsIndexerUnknownToolTestStorage