7 files declare their use of OperationResultInterface in Payment 8.2

CompletePaymentTest.php in tests/src/Unit/Controller/CompletePaymentTest.php

PaymentAccessControlHandlerTest.php in tests/src/Unit/Entity/Payment/PaymentAccessControlHandlerTest.php

PaymentCaptureFormTest.php in tests/src/Unit/Entity/Payment/PaymentCaptureFormTest.php

PaymentFormTest.php in modules/payment_form/tests/src/Unit/Entity/Payment/PaymentFormTest.php

PaymentMethodBaseTest.php in tests/src/Unit/Plugin/Payment/Method/PaymentMethodBaseTest.php

PaymentReferenceBaseTest.php in tests/src/Unit/Element/PaymentReferenceBaseTest.php

PaymentRefundFormTest.php in tests/src/Unit/Entity/Payment/PaymentRefundFormTest.php