# Copyright (c) 2021 PaddlePaddle Authors. All Rights Reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

import sys

import numpy as np
import paddle
import scipy.stats

sys.path.append("../")
from op_test import OpTest

paddle.enable_static()


class TestDirichletOp(OpTest):
    # Because dirichlet random sample have not gradient, we skip gradient check.
    no_need_check_grad = True

    def setUp(self):
        self.op_type = "dirichlet"
        self.alpha = np.array((1., 2.))
        self.sample_shape = (100000, 2)

        self.inputs = {'Alpha': np.broadcast_to(self.alpha, self.sample_shape)}
        self.attrs = {}
        self.outputs = {'Out': np.zeros(self.sample_shape)}

    def test_check_output(self):
        self.check_output_customized(self._hypothesis_testing)

    def _hypothesis_testing(self, outs):
        self.assertEqual(outs[0].shape, self.sample_shape)
        self.assertTrue(np.all(outs[0] > 0.0))
        self.assertLess(
            scipy.stats.kstest(
                outs[0][:, 0],
                # scipy dirichlet have not cdf, use beta to replace it.
                scipy.stats.beta(a=self.alpha[0], b=self.alpha[1]).cdf)[0],
            0.01)