octave:20> test ClassificationGAM
***** test
 CVMdl = crossval (obj);
 assert (class (CVMdl), "ClassificationPartitionedModel")
 assert ({CVMdl.X, CVMdl.Y}, {x, y})
 assert (CVMdl.KFold == 4)
 assert (class (CVMdl.Trained{1}), "CompactClassificationGAM")
 assert (CVMdl.CrossValidatedModel, "ClassificationGAM")
!!!!! test failed
cvpartition: K value for 'kfold' must be an integer scalar in the range [1, n).
shared variables 
    x =

       1   2   3
       4   5   6
       7   8   9
       3   2   1
       4   5   6

    y =

       0
       0
       1
       1
       0

    obj =

      ClassificationGAM object with properties:

                        X: [1, 2, 3; 4, 5, 6; 7, 8, 9; 3, ...]
                        Y: [0; 0; 1; 1; 0]
          NumObservations: 5
                 RowsUsed: [1; 1; 1; 1; 1]
            NumPredictors: 3
           PredictorNames: [1x3 cell]
             ResponseName: "Y"
               ClassNames: [2x1 cell]
                    Prior: []
                     Cost: [0, 1; 1, 0]
           ScoreTransform: 'none'
                  Formula: []
             Interactions: []
                    Knots: [5, 5, 5]
                    Order: [3, 3, 3]
                      DoF: [8, 8, 8]
             LearningRate: 0.1000
            NumIterations: 100
                BaseModel: [1x1 struct]
                ModelwInt: []
                IntMatrix: []