diff --git a/tripleo_common/tests/utils/test_config.py b/tripleo_common/tests/utils/test_config.py
index 208349d26..57727f725 100644
--- a/tripleo_common/tests/utils/test_config.py
+++ b/tripleo_common/tests/utils/test_config.py
@@ -1039,3 +1039,107 @@ class OvercloudConfigTest(base.TestCase):
                          'config-download-latest'))
         mock_os_unlink.assert_called_once_with(
             '/var/lib/mistral/config-download-latest')
+
+    @patch.object(ooo_config.Config, '_open_file')
+    def test_overcloud_config__write_tasks_per_step(self, mock_open_file):
+        heat = mock.MagicMock()
+        self.config = ooo_config.Config(heat)
+
+        # TODO: how can I share this tasks definition between to test
+        # as a fixture So that I do two several test cases instead of
+        # a big one.
+        tasks = [
+            {
+                "when": "step|int == 0",
+                "name": "Simple check"
+            },
+            {
+                "when": "(step|int == 0)",
+                "name": "Check within parenthesis"
+            },
+            {
+                "when": ["step|int == 0", "test1", False],
+                "name": "Check with list with boolean"
+            },
+            {
+                "when": ["test1", False, "step|int == 0"],
+                "name": "Check with list with boolean other order"
+            },
+            {
+                "when": "step|int == 0 or step|int == 3",
+                "name": "Check with boolean expression"
+            },
+            {
+                "when": "(step|int == 0 or step|int == 3) and other_cond",
+                "name": "Complex boolean expression"
+            },
+            {
+                "name": "Task with no conditional"
+            }
+        ]
+
+        # Everything should come back
+        tasks_per_step = self.config._write_tasks_per_step(
+            tasks,
+            'Compute/update_tasks_step0.yaml',
+            0
+        )
+
+        self.assertEqual(tasks, tasks_per_step)
+
+        # Using stict the tasks with no conditional will be dropped
+        tasks_per_step = self.config._write_tasks_per_step(
+            tasks,
+            'Compute/update_tasks_step0.yaml',
+            0,
+            strict=True,
+        )
+
+        expected_tasks = [task for task in tasks
+                          if task != {"name": "Task with no conditional"}]
+        self.assertEqual(expected_tasks,
+                         tasks_per_step)
+
+        # Some tasks will be filtered out for step 3.
+        tasks_per_step = self.config._write_tasks_per_step(
+            tasks,
+            'Compute/update_tasks_step3.yaml',
+            3
+        )
+
+        self.assertEqual(
+            [
+                {
+                    "when": "step|int == 0 or step|int == 3",
+                    "name": "Check with boolean expression"
+                },
+                {
+                    "when": "(step|int == 0 or step|int == 3) and other_cond",
+                    "name": "Complex boolean expression"
+                },
+                {
+                    "name": "Task with no conditional"
+                }
+            ],
+            tasks_per_step)
+
+        # Even more tasks will be filtered out for step 3 with strict.
+        tasks_per_step = self.config._write_tasks_per_step(
+            tasks,
+            'Compute/update_tasks_step3.yaml',
+            3,
+            strict=True,
+        )
+
+        self.assertEqual(
+            [
+                {
+                    "when": "step|int == 0 or step|int == 3",
+                    "name": "Check with boolean expression"
+                },
+                {
+                    "when": "(step|int == 0 or step|int == 3) and other_cond",
+                    "name": "Complex boolean expression"
+                },
+            ],
+            tasks_per_step)
diff --git a/tripleo_common/utils/config.py b/tripleo_common/utils/config.py
index 3487f8bd6..8a48d4c16 100644
--- a/tripleo_common/utils/config.py
+++ b/tripleo_common/utils/config.py
@@ -135,21 +135,22 @@ class Config(object):
                     return False
             if not isinstance(whenexpr, list):
                 whenexpr = [whenexpr]
-            for w in whenexpr:
-                # "when" accepts booleans and regex only work for strings
-                if not isinstance(w, six.string_types):
-                    continue
-                # remove all spaces to make the regex match easier
-                w = re.sub(r'\s+', '', w)
-                # make \|int optional incase forgotten; use only step digit:
-                # ()'s around step|int are also optional
-                match = re.search(r'\(?step(\|int)?\)?==([0-9]+)$', "%s" % w)
-                if match:
-                    if match.group(2) == str(step):
-                        return True
-                    else:
-                        return False
-            # No match
+
+            # Filter out boolean value and remove blanks
+            flatten_when = "".join([re.sub(r'\s+', '', x)
+                                    for x in whenexpr
+                                    if isinstance(x, six.string_types)])
+            # make \|int optional incase forgotten; use only step digit:
+            # ()'s around step|int are also optional
+            steps_found = re.findall(r'\(?step(?:\|int)?\)?==(\d+)',
+                                     flatten_when)
+            if steps_found:
+                if str(step) in steps_found:
+                    return True
+                else:
+                    return False
+
+            # No step found
             if strict:
                 return False
             return True