@Test
void success() {

    final PurchaseResult result = PurchaseResult.success();
    SoftAssertions.assertSoftly(softly -> {
        softly.assertThat(result.isSuccess())
            .isTrue();
        softly.assertThat(result.getFailureType())
            .isEmpty();
        softly.assertThat(result)
            .isSameAs(PurchaseResult.success());
    });
}