diff --git a/lint4jsondb.py b/lint4jsondb.py
index b2a5af0..a35f4f9 100644
--- a/lint4jsondb.py
+++ b/lint4jsondb.py
@@ -183,6 +183,12 @@ def finish(self):
 
                 continue
 
+        # apply the directory to relative paths if needed
+        self.file = os.path.normpath(os.path.join(self.directory, self.file))
+        self.invocation.includes = [
+            os.path.normpath(os.path.join(self.directory, inc))
+            for inc in self.invocation.includes]
+
 
 class Lint4JsonCompilationDb:
     def __init__(self, compilation_db, include_only=set(), exclude_all=set()):
@@ -317,7 +323,8 @@ def execute_with(self, arg, json_db):
 
 class ExecuteLintForAllFilesInOneInvocation:
     def __init__(self):
-        self._tmp_file = tempfile.NamedTemporaryFile(mode='w+', delete=False, suffix='.lnt')
+        self._tmp_file = tempfile.NamedTemporaryFile(
+            mode='w+', delete=False, suffix='.lnt')
         self._last_invocation = None
 
     def _create_temporary_lint_config(self, json_db):
diff --git a/test_lint4jsondb.py b/test_lint4jsondb.py
index 58b6a5a..9e70fee 100644
--- a/test_lint4jsondb.py
+++ b/test_lint4jsondb.py
@@ -19,7 +19,7 @@ def tearDown(self):
             os.remove(self._json_tested)
 
     def __create_temp_json(self, content):
-        with tempfile.TemporaryFile('wb', delete=False) as f:
+        with tempfile.NamedTemporaryFile('wb', delete=False) as f:
             self._json_tested = f.name
             f.write(content)
 
@@ -264,7 +264,8 @@ def test_invocation(self, mock_call, mock_os_path_exists, mock_os_makedirs):
                               'stderr': -2, 'stdout': -1})
 
         # ensure lint is called
-        self.assertEqual(args.pop(0), os.path.join("<lint-path>", "<lint-exe>"))
+        self.assertEqual(args.pop(0), os.path.join(
+            "<lint-path>", "<lint-exe>"))
         # ensure lint suppresses the banner line
         self.assertEqual(args.pop(0), '-b')
         # ensure lint's "lnt" directory was added
@@ -280,3 +281,7 @@ def test_invocation(self, mock_call, mock_os_path_exists, mock_os_makedirs):
         self.assertEqual(args.pop(0), '-i"i2"')
         # ensure that the file to check is passed finally
         self.assertEqual(args.pop(0), "<file>")
+
+
+if __name__ == "__main__":
+    unittest.main()