message: add missing scalar check
diff: @@ -120,6 +120,7 @@ TEST_F(Perturbation, CanCreateFromTwoOperators)
  ASSERT_EQ(cmp->get_size(), gko::dim<2>(2, 2));
  ASSERT_EQ(cmp->get_basis(), basis);
  ASSERT_EQ(cmp->get_projector(), projector);
  + ASSERT_EQ(cmp->get_scalar(), scalar);
  }
  @@ -136,6 +137,7 @@ TEST_F(Perturbation, CanCreateFromOneTranposableOperator)
  ASSERT_EQ(cmp->get_size(), gko::dim<2>(3, 3));
  ASSERT_EQ(cmp->get_basis(), trans_basis);
  ASSERT_EQ(cmp->get_projector()->get_size(), gko::dim<2>(1, 3));
  + ASSERT_EQ(cmp->get_scalar(), scalar);
  }
  