🧪 [#4980] Add test for select component with a form variable as a dat…

…a source

When a select component has a form variable as data source, the 'enum' property in the JSON schema is currently unfilled, because the 'values' option of the component is an empty list.

Solution is to fetch the corresponding form variable and update the 'enum' property in the schema accordingly

src/openforms/forms/tests/test_form_to_json_schema.py

@@ -4,6 +4,7 @@
     FormDefinitionFactory,
     FormFactory,
     FormStepFactory,
+    FormVariableFactory,
 )
 from openforms.forms.utils import form_variables_to_json_schema
 
@@ -80,8 +81,43 @@ def test_form_to_json_schema(self):
             "auth_bsn",
             "today",
         )
-        var_properties = form_variables_to_json_schema(form, vars_to_include)
+        schema = form_variables_to_json_schema(form, vars_to_include)
 
-        from pprint import pprint
-        pprint(var_properties)
+    def test_select_component_with_form_variable_as_data_source(self):
+        form = FormFactory.create()
+        form_def_1 = FormDefinitionFactory.create(
+            configuration={
+                "components": [
+                    {
+                        "label": "Select",
+                        "key": "select",
+                        "type": "select",
+                        "openForms": {
+                            "dataSrc": "variable",
+                            "translations": {},
+                            "itemsExpression": {"var": "valuesForSelect"}
+                        },
+                        "data": {
+                            "values": [],
+                            "json": "",
+                            "url": "",
+                            "resource": "",
+                            "custom": "",
+                        },
+                    },
+                ]
+            }
+        )
+        form_step_1 = FormStepFactory.create(form=form, form_definition=form_def_1)
+
+        FormVariableFactory.create(
+            form=form,
+            name="Values for select",
+            key="valuesForSelect",
+            user_defined=True,
+            initial_value=["A", "B", "C"]
+        )
+
+        schema = form_variables_to_json_schema(form, ["select"])
 
+        self.assertEqual(schema["properties"]["select"]["enum"], ["A", "B", "C"])