Add support for complex template structures to data_template (#3255)

tests/helpers/test_config_validation.py

@@ -299,9 +299,7 @@ def test_template():
     """Test template validator."""
     schema = vol.Schema(cv.template)
 
-    for value in (
-        None, '{{ partial_print }', '{% if True %}Hello', {'dict': 'isbad'}
-    ):
+    for value in (None, '{{ partial_print }', '{% if True %}Hello', ['test']):
         with pytest.raises(vol.MultipleInvalid):
             schema(value)
 
@@ -313,6 +311,24 @@ def test_template():
         schema(value)
 
 
+def test_template_complex():
+    """Test template_complex validator."""
+    schema = vol.Schema(cv.template_complex)
+
+    for value in (None, '{{ partial_print }', '{% if True %}Hello'):
+        with pytest.raises(vol.MultipleInvalid):
+            schema(value)
+
+    for value in (
+        1, 'Hello',
+        '{{ beer }}',
+        '{% if 1 == 1 %}Hello{% else %}World{% endif %}',
+        {'test': 1, 'test': '{{ beer }}'},
+        ['{{ beer }}', 1]
+    ):
+        schema(value)
+
+
 def test_time_zone():
     """Test time zone validation."""
     schema = vol.Schema(cv.time_zone)