diff --git a/ate/testcase.py b/ate/testcase.py
index 408d0c2b..0a8ff18e 100644
--- a/ate/testcase.py
+++ b/ate/testcase.py
@@ -192,7 +192,16 @@ def substitute_variables_with_mapping(content, mapping):
             }
         }
     """
-    if isinstance(content, (list, tuple)):
+    if isinstance(content, bool):
+        return content
+
+    if isinstance(content, (int, utils.long_type, float, complex)):
+        return content
+
+    if not content:
+        return content
+
+    if isinstance(content, (list, set, tuple)):
         return [
             substitute_variables_with_mapping(item, mapping)
             for item in content
@@ -207,9 +216,6 @@ def substitute_variables_with_mapping(content, mapping):
 
         return substituted_data
 
-    if isinstance(content, (int, utils.long_type, float, complex)):
-        return content
-
     # content is in string format here
     for var, value in mapping.items():
         if content == var:
diff --git a/tests/test_testcase.py b/tests/test_testcase.py
index 0a19345e..c6919b85 100644
--- a/tests/test_testcase.py
+++ b/tests/test_testcase.py
@@ -428,7 +428,13 @@ class TestcaseParserUnittest(unittest.TestCase):
             'request': {
                 'url': '/api/users/$uid',
                 'method': "$method",
-                'headers': {'token': '$token'}
+                'headers': {'token': '$token'},
+                'data': {
+                    "null": None,
+                    "true": True,
+                    "false": False,
+                    "empty_str": ""
+                }
             }
         }
         mapping = {
@@ -439,6 +445,10 @@ class TestcaseParserUnittest(unittest.TestCase):
         self.assertEqual("/api/users/1000", result["request"]["url"])
         self.assertEqual("$token", result["request"]["headers"]["token"])
         self.assertEqual("POST", result["request"]["method"])
+        self.assertIsNone(result["request"]["data"]["null"])
+        self.assertTrue(result["request"]["data"]["true"])
+        self.assertFalse(result["request"]["data"]["false"])
+        self.assertEqual("", result["request"]["data"]["empty_str"])
 
     def test_load_api_definition(self):
         path = os.path.join(