diff --git a/tests/app/main/test_placeholder_form.py b/tests/app/main/test_placeholder_form.py
new file mode 100644
index 000000000..07fac6675
--- /dev/null
+++ b/tests/app/main/test_placeholder_form.py
@@ -0,0 +1,18 @@
+from app.main.forms import get_placeholder_form_instance
+from wtforms import Label
+
+
+def test_form_class_not_mutated(app_):
+
+    with app_.test_request_context(
+        method='POST',
+        data={'placeholder_value': ''}
+    ) as req:
+        form1 = get_placeholder_form_instance('name', {}, optional_placeholder=False)
+        form2 = get_placeholder_form_instance('city', {}, optional_placeholder=True)
+
+        assert not form1.validate_on_submit()
+        assert form2.validate_on_submit()
+
+        assert str(form1.placeholder_value.label) == '<label for="placeholder_value">name</label>'
+        assert str(form2.placeholder_value.label) == '<label for="placeholder_value">city</label>'