The @dataProvider annotation should be a static function, check and make data provider in the extension, at least:
- AllLabelsFieldTest with provideFieldData
- DescriptionFieldTest with getFieldDataProvider
- abstract WikibaseNumericFieldTestCase with getFieldDataProvider
- LabelsFieldTest with getFieldDataProvider
- StatementQuantityFieldTest with statementsProvider
static and adjust the usages (More infos at T332865).
Initial work was done in bd214aeaafd6b16f227b11eb2bd6348894d900c7