Add custom form field wrapper to determine if form data has changes

atst/forms/fields.py

@@ -1,4 +1,4 @@
-from wtforms.fields import Field, StringField, SelectField as SelectField_
+from wtforms.fields import Field, FormField, StringField, SelectField as SelectField_
 from wtforms.widgets import TextArea
 
 
@@ -39,3 +39,14 @@ class NumberStringField(StringField):
             self.data = str(value)
         else:
             self.data = value
+
+
+class FormFieldWrapper(FormField):
+    def has_changes(self):
+        if not self.object_data:
+            return False
+
+        for (attr, field) in self._fields.items():
+            if attr in self.object_data and self.object_data[attr] != field.data:
+                return True
+        return False

tests/forms/test_fields.py

@@ -1,9 +1,10 @@
 import pytest
 from wtforms import Form
+from wtforms.fields import StringField
 import pendulum
 from werkzeug.datastructures import ImmutableMultiDict
 
-from atst.forms.fields import NewlineListField
+from atst.forms.fields import NewlineListField, FormFieldWrapper
 
 
 class NewlineListForm(Form):
@@ -38,3 +39,37 @@ def test_newline_list_value(input_, expected):
 
     assert form.validate()
     assert form.newline_list._value() == expected
+
+
+class PersonForm(Form):
+    first_name = StringField("first_name")
+
+
+class FormWithFormField(Form):
+    person = FormFieldWrapper(PersonForm)
+
+
+class TestFormFieldWrapper:
+    class Foo:
+        person = {"first_name": "Luke"}
+
+    obj = Foo()
+
+    def test_form_data_does_not_match_object_data(self):
+        form_data = ImmutableMultiDict({"person-first_name": "Han"})
+        form = FormWithFormField(form_data, obj=self.obj)
+        assert form.person.has_changes()
+
+    def test_when_no_form_data(self):
+        form = FormWithFormField(None, obj=self.obj)
+        assert not form.person.has_changes()
+
+    def test_when_no_obj_data(self):
+        form_data = ImmutableMultiDict({"person-first_name": "Han"})
+        form = FormWithFormField(form_data)
+        assert not form.person.has_changes()
+
+    def test_when_form_data_matches_obj_dta(self):
+        form_data = ImmutableMultiDict({"person-first_name": "Luke"})
+        form = FormWithFormField(form_data, obj=self.obj)
+        assert not form.person.has_changes()