from __future__ import print_function
import sys
import os
import re
import math
import shutil
import random
import tempfile
import unittest
import traceback
import torch
import torch.nn as nn
import torch.utils.data
import torch.cuda
import warnings
from torch.utils.checkpoint import checkpoint, checkpoint_sequential
from torch.utils.trainer import Trainer
from torch.utils.trainer.plugins import *
from torch.utils.trainer.plugins.plugin import Plugin
from torch.utils.serialization import load_lua
from torch.autograd._functions.utils import prepare_onnx_paddings
from torch.autograd._functions.utils import check_onnx_broadcast
from common import IS_WINDOWS

HAS_CUDA = torch.cuda.is_available()

from common import TestCase, run_tests, download_file

try:
    import cffi
    HAS_CFFI = True
except ImportError:
    HAS_CFFI = False


if HAS_CFFI:
    from torch.utils.ffi import create_extension


class SimplePlugin(Plugin):

    def __init__(self, interval):
        super(SimplePlugin, self).__init__(interval)
        self.trainer = None
        self.num_iteration = 0
        self.num_epoch = 0
        self.num_batch = 0
        self.num_update = 0

    def register(self, trainer):
        self.trainer = trainer

    def iteration(self, *args):
        self.iteration_args = args
        self.num_iteration += 1

    def epoch(self, *args):
        self.epoch_args = args
        self.num_epoch += 1

    def batch(self, *args):
        self.batch_args = args
        self.num_batch += 1

    def update(self, *args):
        self.update_args = args
        self.num_update += 1


class ModelMock(object):

    def __init__(self):
        self.num_calls = 0
        self.output = torch.ones(1, 1, requires_grad=True)

    def __call__(self, i):
        self.num_calls += 1
        return self.output * 2


class CriterionMock(object):

    def __init__(self):
        self.num_calls = 0

    def __call__(self, out, target):
        self.num_calls += 1
        return out


class OptimizerMock(object):
    max_evals = 5
    min_evals = 1

    def __init__(self):
        self.num_steps = 0
        self.num_evals = 0

    def step(self, closure):
        for i in range(random.randint(self.min_evals, self.max_evals)):
            loss = closure()
            self.num_evals += 1
        self.num_steps += 1

    def zero_grad(self):
        pass


class DatasetMock(object):

    def __iter__(self):
        for i in range(10):
            yield torch.randn(2, 10), torch.randperm(10)[:2]

    def __len__(self):
        return 10


class TestCheckpoint(TestCase):

    # Test whether checkpoint is being triggered or not. For this, we check
    # the number of times forward pass happens
    def test_checkpoint_trigger(self):

        class Net(nn.Module):

            def __init__(self):
                super(Net, self).__init__()
                self.counter = 0

            def forward(self, input_var):
                self.counter += 1
                return input_var

        # checkpointed
        modules = [Net() for _ in range(10)]
        for m in modules:
            self.assertEqual(m.counter, 0)
        input_var = torch.randn(3, 4, requires_grad=True)
        out = checkpoint_sequential(modules, 2, input_var)
        for m in modules:
            self.assertEqual(m.counter, 1)
        out.sum().backward()
        for m in modules[:(len(modules) // 2)]:
            self.assertEqual(m.counter, 2)
        for m in modules[(len(modules) // 2):]:
            self.assertEqual(m.counter, 1)

    def test_checkpoint_valid(self):
        model = nn.Sequential(
            nn.Linear(100, 50),
            nn.ReLU(),
            nn.Linear(50, 20),
            nn.ReLU(),
            nn.Linear(20, 5),
            nn.ReLU()
        )

        input_var = torch.randn(1, 100, requires_grad=True)

        # checkpointed
        chunks = 2
        modules = list(model.children())
        out = checkpoint_sequential(modules, chunks, input_var)
        with self.assertRaisesRegex(RuntimeError, "Checkpointing is not compatible"):
            torch.autograd.grad(
                outputs=[out], grad_outputs=[torch.ones(1, 5)], inputs=[input_var], create_graph=True
            )

    def test_checkpoint(self):
        model = nn.Sequential(
            nn.Linear(100, 50),
            nn.ReLU(),
            nn.Linear(50, 20),
            nn.ReLU(),
            nn.Linear(20, 5),
            nn.ReLU()
        )

        x = torch.randn(1, 100, requires_grad=True)

        # not checkpointed
        out = model(x)
        out_not_checkpointed = out.data.clone()
        model.zero_grad()
        out.sum().backward()
        grad_not_checkpointed = {}
        for name, param in model.named_parameters():
            grad_not_checkpointed[name] = param.grad.data.clone()
        input_grad = x.grad.data.clone()

        # checkpointed model by passing list of modules
        chunks = 2
        modules = list(model.children())
        input_var = x.detach()
        input_var.requires_grad = True
        # pass list of modules to checkpoint
        out = checkpoint_sequential(modules, chunks, input_var)
        out_checkpointed = out.data.clone()
        model.zero_grad()
        out.sum().backward()
        grad_checkpointed = {}
        for name, param in model.named_parameters():
            grad_checkpointed[name] = param.grad.data.clone()
        checkpoint_input_grad = input_var.grad.data.clone()
        # compare the output, input and parameters gradients
        self.assertEqual(out_checkpointed, out_not_checkpointed)
        self.assertEqual(input_grad, checkpoint_input_grad)
        for name in grad_checkpointed:
            self.assertEqual(grad_checkpointed[name], grad_not_checkpointed[name])

        # checkpointed by passing sequential directly
        input_var1 = x.detach()
        input_var1.requires_grad = True
        # pass the sequential itself
        out = checkpoint_sequential(model, 2, input_var1)
        out_checkpointed = out.data.clone()
        model.zero_grad()
        out.sum().backward()
        grad_checkpointed = {}
        for name, param in model.named_parameters():
            grad_checkpointed[name] = param.grad.data.clone()
        checkpoint_input_grad = input_var1.grad.data.clone()
        # compare the output, input and parameters gradients
        self.assertEqual(out_checkpointed, out_not_checkpointed)
        self.assertEqual(input_grad, checkpoint_input_grad)
        for name in grad_checkpointed:
            self.assertEqual(grad_checkpointed[name], grad_not_checkpointed[name])


class TestDataLoader(TestCase):
    def setUp(self):
        self.dataset = torch.randn(5, 3, 3, 2)
        self.batch_size = 3

    def test_single_keep(self):
        dataloader = torch.utils.data.DataLoader(self.dataset,
                                                 batch_size=self.batch_size,
                                                 num_workers=0,
                                                 drop_last=False)
        dataiter = iter(dataloader)
        self.assertEqual(len(list(dataiter)), 2)

    def test_single_drop(self):
        dataloader = torch.utils.data.DataLoader(self.dataset,
                                                 batch_size=self.batch_size,
                                                 num_workers=0,
                                                 drop_last=True)
        dataiter = iter(dataloader)
        self.assertEqual(len(list(dataiter)), 1)

    @unittest.skip("FIXME: Intermittent CUDA out-of-memory error on Windows and time-out under ASAN")
    def test_multi_keep(self):
        dataloader = torch.utils.data.DataLoader(self.dataset,
                                                 batch_size=self.batch_size,
                                                 num_workers=2,
                                                 drop_last=False)
        dataiter = iter(dataloader)
        self.assertEqual(len(list(dataiter)), 2)

    @unittest.skipIf(IS_WINDOWS, "FIXME: Intermittent CUDA out-of-memory error")
    def test_multi_drop(self):
        dataloader = torch.utils.data.DataLoader(self.dataset,
                                                 batch_size=self.batch_size,
                                                 num_workers=2,
                                                 drop_last=True)
        dataiter = iter(dataloader)
        self.assertEqual(len(list(dataiter)), 1)


class TestTrainer(TestCase):

    intervals = [
        [(1, 'iteration')],
        [(1, 'epoch')],
        [(1, 'batch')],
        [(1, 'update')],
        [(5, 'iteration')],
        [(5, 'epoch')],
        [(5, 'batch')],
        [(5, 'update')],
        [(1, 'iteration'), (1, 'epoch')],
        [(5, 'update'), (1, 'iteration')],
        [(2, 'epoch'), (1, 'batch')],
    ]

    def setUp(self):
        self.optimizer = OptimizerMock()
        self.trainer = Trainer(ModelMock(), CriterionMock(),
                               self.optimizer, DatasetMock())
        self.num_epochs = 3
        self.dataset_size = len(self.trainer.dataset)
        self.num_iters = self.num_epochs * self.dataset_size

    def test_register_plugin(self):
        for interval in self.intervals:
            simple_plugin = SimplePlugin(interval)
            self.trainer.register_plugin(simple_plugin)
            self.assertEqual(simple_plugin.trainer, self.trainer)

    def test_optimizer_step(self):
        self.trainer.run(epochs=1)
        self.assertEqual(self.trainer.optimizer.num_steps, 10)

    def test_plugin_interval(self):
        for interval in self.intervals:
            self.setUp()
            simple_plugin = SimplePlugin(interval)
            self.trainer.register_plugin(simple_plugin)
            self.trainer.run(epochs=self.num_epochs)
            units = {
                ('iteration', self.num_iters),
                ('epoch', self.num_epochs),
                ('batch', self.num_iters),
                ('update', self.num_iters)
            }
            for unit, num_triggers in units:
                call_every = None
                for i, i_unit in interval:
                    if i_unit == unit:
                        call_every = i
                        break
                if call_every:
                    expected_num_calls = math.floor(num_triggers / call_every)
                else:
                    expected_num_calls = 0
                num_calls = getattr(simple_plugin, 'num_' + unit)
                self.assertEqual(num_calls, expected_num_calls, 0)

    def test_model_called(self):
        self.trainer.run(epochs=self.num_epochs)
        num_model_calls = self.trainer.model.num_calls
        num_crit_calls = self.trainer.criterion.num_calls
        self.assertEqual(num_model_calls, num_crit_calls)
        for num_calls in [num_model_calls, num_crit_calls]:
            lower_bound = OptimizerMock.min_evals * self.num_iters
            upper_bound = OptimizerMock.max_evals * self.num_iters
            self.assertEqual(num_calls, self.trainer.optimizer.num_evals)
            self.assertLessEqual(lower_bound, num_calls)
            self.assertLessEqual(num_calls, upper_bound)

    def test_model_gradient(self):
        self.trainer.run(epochs=self.num_epochs)
        output_var = self.trainer.model.output
        expected_grad = torch.ones(1, 1) * 2 * self.optimizer.num_evals
        self.assertEqual(output_var.grad.data, expected_grad)


test_dir = os.path.abspath(os.path.dirname(str(__file__)))


class TestFFI(TestCase):

    def setUp(self):
        self.tmpdir = tempfile.mkdtemp()
        os.chdir(self.tmpdir)
        sys.path.append(self.tmpdir)

    def tearDown(self):
        shutil.rmtree(self.tmpdir)

    @unittest.skipIf(not HAS_CFFI, "ffi tests require cffi package")
    @unittest.skipIf(IS_WINDOWS, "ffi doesn't currently work on Windows")
    def test_cpu(self):
        create_extension(
            name='test_extensions.cpulib',
            headers=[test_dir + '/ffi/src/cpu/lib.h'],
            sources=[
                test_dir + '/ffi/src/cpu/lib1.c',
                test_dir + '/ffi/src/cpu/lib2.c',
            ],
            verbose=False,
        ).build()
        from test_extensions import cpulib
        tensor = torch.ones(2, 2).float()

        cpulib.good_func(tensor, 2, 1.5)
        self.assertEqual(tensor, torch.ones(2, 2) * 2 + 1.5)

        new_tensor = cpulib.new_tensor(4)
        self.assertEqual(new_tensor, torch.ones(4, 4) * 4)

        f = cpulib.int_to_float(5)
        self.assertIs(type(f), float)

        self.assertRaises(TypeError,
                          lambda: cpulib.good_func(tensor.double(), 2, 1.5))
        self.assertRaises(torch.FatalError,
                          lambda: cpulib.bad_func(tensor, 2, 1.5))

    @unittest.skipIf(not HAS_CFFI or not HAS_CUDA, "ffi tests require cffi package")
    @unittest.skipIf(IS_WINDOWS, "ffi doesn't currently work on Windows")
    def test_gpu(self):
        create_extension(
            name='gpulib',
            headers=[test_dir + '/ffi/src/cuda/cudalib.h'],
            sources=[
                test_dir + '/ffi/src/cuda/cudalib.c',
            ],
            with_cuda=True,
            verbose=False,
        ).build()
        import gpulib
        tensor = torch.ones(2, 2).float()

        gpulib.good_func(tensor, 2, 1.5)
        self.assertEqual(tensor, torch.ones(2, 2) * 2 + 1.5)

        ctensor = tensor.cuda().fill_(1)
        gpulib.cuda_func(ctensor, 2, 1.5)
        self.assertEqual(ctensor, torch.ones(2, 2) * 2 + 1.5)

        self.assertRaises(TypeError,
                          lambda: gpulib.cuda_func(tensor, 2, 1.5))
        self.assertRaises(TypeError,
                          lambda: gpulib.cuda_func(ctensor.storage(), 2, 1.5))


class TestLuaReader(TestCase):

    @staticmethod
    def _module_test(name, test):
        def do_test(self):
            module = test['module']
            input = test['input']
            grad_output = test['grad_output']
            if hasattr(self, '_transform_' + name):
                input = getattr(self, '_transform_' + name)(input)
            output = module.forward(input)
            module.zeroGradParameters()
            grad_input = module.backward(input, grad_output)
            self.assertEqual(output, test['output'])
            self.assertEqual(grad_input, test['grad_input'])
            if module.parameters() is not None:
                params, d_params = module.parameters()
                self.assertEqual(params, test['params'])
                self.assertEqual(d_params, test['d_params'])
            else:
                self.assertFalse('params' in test and test['params'])
                self.assertFalse('params' in test and test['d_params'])
        return do_test

    @staticmethod
    def _criterion_test(name, test):
        def do_test(self):
            module = test['module']
            input = test['input']
            if name == 'L1Cost':
                target = None
            else:
                target = test['target']
            if hasattr(self, '_transform_' + name):
                input, target = getattr(self, '_transform_' + name)(input, target)

            output = module.forward(input, target)
            grad_input = module.backward(input, target)
            self.assertEqual(output, test['loss'])
            self.assertEqual(grad_input, test['grad_input'])
        return do_test

    @classmethod
    def init(cls):
        try:
            path = download_file('https://download.pytorch.org/test_data/legacy_modules.t7')
        except unittest.SkipTest:
            return
        long_size = 8 if sys.platform == 'win32' else None
        tests = load_lua(path, long_size=long_size)
        for name, test in tests['modules'].items():
            test_name = 'test_' + name.replace('nn.', '')
            setattr(cls, test_name, cls._module_test(name, test))
        for name, test in tests['criterions'].items():
            test_name = 'test_' + name.replace('nn.', '')
            setattr(cls, test_name, cls._criterion_test(name, test))

    def _transform_Index(self, input):
        return [input[0], input[1].sub(1)]

    def _transform_LookupTable(self, input):
        return input.sub(1)

    def _transform_MultiLabelMarginCriterion(self, input, target):
        return input, target.sub(1)

    def _transform_ClassNLLCriterion(self, input, target):
        return input, target.sub(1)

    def _transform_SpatialClassNLLCriterion(self, input, target):
        return input, target.sub(1)

    def _transform_ClassSimplexCriterion(self, input, target):
        return input, target.sub(1)

    def _transform_CrossEntropyCriterion(self, input, target):
        return input, target.sub(1)

    def _transform_ParallelCriterion(self, input, target):
        return input, [target[0].sub(1), target[1]]

    def _transform_MultiCriterion(self, input, target):
        return input, target.sub(1)

    def _transform_MultiMarginCriterion(self, input, target):
        return input, target.sub(1)


class TestBottleneck(TestCase):
    def _run(self, command):
        """Returns (return-code, stdout, stderr)"""
        import subprocess
        from common import PY3

        p = subprocess.Popen(command, stdout=subprocess.PIPE,
                             stderr=subprocess.PIPE, shell=True)
        output, err = p.communicate()
        rc = p.returncode
        if PY3:
            output = output.decode("ascii")
            err = err.decode("ascii")
        return (rc, output, err)

    def _run_bottleneck(self, test_file, scriptargs=''):
        curdir = os.path.dirname(os.path.abspath(__file__))
        filepath = '{}/{}'.format(curdir, test_file)
        if scriptargs != '':
            scriptargs = ' {}'.format(scriptargs)
        rc, out, err = self._run(
            'python -m torch.utils.bottleneck {}{}'.format(filepath, scriptargs))
        return rc, out, err

    def _check_run_args(self):
        # Check that this fails due to missing args
        rc, out, err = self._run_bottleneck('bottleneck/test_args.py')
        self.assertEqual(rc, 2, None, self._fail_msg('Missing args should error', out + err))

        # This should succeed
        rc, out, err = self._run_bottleneck('bottleneck/test_args.py', '--foo foo --bar bar')
        self.assertEqual(rc, 0, None, self._fail_msg('Should pass args to script', out + err))

    def _fail_msg(self, msg, output):
        return '{}, output was:\n{}'.format(msg, output)

    def _check_environment_summary(self, output):
        results = re.search('Environment Summary', output)
        self.assertIsNotNone(results, self._fail_msg('Should have Enviroment Summary', output))

        # Up to five lines away from the heading, there should be the version number
        results = re.search(r'Environment Summary.*(\n.*){,5}\nPyTorch \d+\.\d+', output)
        self.assertIsNotNone(results, self._fail_msg('Should have PyTorch version', output))

    def _check_cprof_summary(self, output):
        results = re.search('cProfile output', output)
        self.assertIsNotNone(results, self._fail_msg('Should have cProfile output', output))

        # This assumes that after the cProfile output section we have
        # the autograd profiler output
        results = re.search(r'cProfile output.*(\n.*){6,50}\n.*autograd profiler output', output)
        self.assertIsNotNone(results, self._fail_msg(
            'Distance between cProfile and autograd prof out not in [6, 50] lines', output))

    def _check_autograd_summary(self, output):
        results = re.search('autograd profiler output', output)
        self.assertIsNotNone(results, self._fail_msg('Should have autograd profiler output', output))

        # This assumes that after the autograd profiler output is the end of the
        # output.
        results = re.search(r'autograd profiler output.*(\n.*){6,100}', output)
        self.assertIsNotNone(results, self._fail_msg(
            'Distance between autograd prof output and end of output not in [6, 100] lines', output))

    def _check_cuda(self, output):
        if torch.cuda.is_available():
            results = re.search('CUDA mode', output)
            self.assertIsNotNone(results, self._fail_msg('Should tell users CUDA', output))
        else:
            results = re.search('CUDA mode', output)
            self.assertIsNone(results, self._fail_msg('Should not tell users about CUDA', output))

    @unittest.skipIf(torch.cuda.is_available(), 'CPU-only test')
    def test_bottleneck_cpu_only(self):
        rc, out, err = self._run_bottleneck('bottleneck/test.py')
        self.assertEqual(rc, 0, 'Run failed with\n{}'.format(err))

        self._check_run_args()
        self._check_environment_summary(out)
        self._check_autograd_summary(out)
        self._check_cprof_summary(out)
        self._check_cuda(out)

    @unittest.skipIf(IS_WINDOWS, "FIXME: Intermittent CUDA out-of-memory error")
    @unittest.skipIf(not torch.cuda.is_available(), 'No CUDA')
    def test_bottleneck_cuda(self):
        rc, out, err = self._run_bottleneck('bottleneck/test_cuda.py')
        self.assertEqual(rc, 0, 'Run failed with\n{}'.format(err))

        self._check_run_args()
        self._check_environment_summary(out)
        self._check_autograd_summary(out)
        self._check_cprof_summary(out)
        self._check_cuda(out)


from torch.utils.collect_env import get_pretty_env_info


class TestCollectEnv(TestCase):

    def _build_env_to_expect(self, build_env):
        return 'expect/TestCollectEnv.test_{}.expect'.format(
            build_env.replace('.', '').replace('-', '_'))

    def _preprocess_info_for_test(self, info_output):
        # Remove the version hash
        version_hash_regex = re.compile(r'(a\d+)\+.......')
        result = re.sub(version_hash_regex, r'\1', info_output).strip()

        # Substitutions to lower the specificity of the versions listed
        substitutions = [
            (r'(?<=CUDA used to build PyTorch: )(\d+)\.(\d+)\.(\d+)', r'\1.\2.X'),
            (r'(?<=CUDA runtime version: )(\d+)\.(\d+)\.(\d+)', r'\1.\2.X'),
            (r'(?<=Ubuntu )(\d+)\.(\d+)\.(\d+) ', r'\1.\2.X '),
            (r'(?<=CMake version: version )(\d+)\.(\d+)\.(\d+)', r'\1.\2.X'),
            (r'(?<=Nvidia driver version: )(\d+)\.(\d+)', r'\1.X'),
            (r'(?<=Mac OSX )(\d+)\.(\d+).(\d+)', r'\1.\2.X'),
            (r'(?<=numpy \()(\d+)\.(\d+).(\d+)', r'\1.\2.X'),
        ]

        for regex, substitute in substitutions:
            result = re.sub(regex, substitute, result)
        return result

    def assertExpectedOutput(self, info_output, build_env):
        processed_info = self._preprocess_info_for_test(info_output)
        expect_filename = self._build_env_to_expect(build_env)

        ci_warning = ('This test will error out if the CI config was recently '
                      'updated. If this is the case, please update the expect '
                      'files to match the CI machines\' system config.')

        with open(expect_filename, 'r') as f:
            expected_info = f.read().strip()
            self.assertEqual(ci_warning + '\n' + processed_info,
                             ci_warning + '\n' + expected_info, ci_warning)

    def test_smoke(self):
        info_output = get_pretty_env_info()
        self.assertTrue(info_output.count('\n') >= 17)

    @unittest.skipIf('BUILD_ENVIRONMENT' not in os.environ.keys(), 'CI-only test')
    def test_expect(self):
        info_output = get_pretty_env_info()

        ci_build_envs = [
            'pytorch-linux-trusty-py2.7',
            'pytorch-linux-xenial-cuda9-cudnn7-py3',
            'pytorch-macos-10.13-py3',
            'pytorch-win-ws2016-cuda9-cudnn7-py3'
        ]
        build_env = os.environ['BUILD_ENVIRONMENT']
        if build_env not in ci_build_envs:
            return

        self.assertExpectedOutput(info_output, build_env)


class TestONNXUtils(TestCase):
    def test_prepare_onnx_paddings(self):
        sizes = [2, 3, 4]
        pad = [1, 2, 3, 4]
        paddings = prepare_onnx_paddings(len(sizes), pad)
        self.assertEqual(paddings, [0, 3, 1, 0, 4, 2])

    def test_check_onnx_broadcast(self):

        def try_check_onnx_broadcast(dims1, dims2, expect_broadcast, expect_fail):
            broadcast = True
            fail = False
            try:
                broadcast = check_onnx_broadcast(dims1, dims2)
            except ValueError:
                fail = True
            self.assertEqual(broadcast, expect_broadcast)
            self.assertEqual(fail, expect_fail)

        # Case 1, check the case when len(dims1) < len(dims2) and numel(dims2) > 1
        dims1 = [3, 4]
        dims2 = [2, 3, 4]
        try_check_onnx_broadcast(dims1, dims2, True, True)

        # Case 2, check the case when len(dims1) < len(dims2) and numel(dims2) == 1
        dims1 = [3, 4]
        dims2 = [1, 1, 1]
        try_check_onnx_broadcast(dims1, dims2, True, False)

        # Case 3, check the case when len(dims1) > len(dims2) and numel(dims2) == 1
        dims1 = [1, 1]
        dims2 = [1]
        try_check_onnx_broadcast(dims1, dims2, True, False)

        # Case 4, check the case when len(dims1) > len(dims2) and dims1[x:] == dims2
        dims1 = [2, 3, 4]
        dims2 = [3, 4]
        try_check_onnx_broadcast(dims1, dims2, True, False)

        # Case 5, check the case when len(dims1) > len(dims2), but dims1[x:] != dims2
        dims1 = [2, 3, 4]
        dims2 = [1, 4]
        try_check_onnx_broadcast(dims1, dims2, True, True)

        # Case 6, check the equal case, no broadcast
        dims1 = [3, 4]
        dims2 = [3, 4]
        try_check_onnx_broadcast(dims1, dims2, False, False)

        # Case 7, check the case when len(dims1) == len(dims2), but dims1 != dims2
        dims1 = [3, 4]
        dims2 = [1, 4]
        try_check_onnx_broadcast(dims1, dims2, True, True)

        # Case 8, check the case when len(dims1) == len(dims2) and numel(s2) == 1
        dims1 = [3, 4]
        dims2 = [1, 1]
        try_check_onnx_broadcast(dims1, dims2, True, False)


TestLuaReader.init()
if __name__ == '__main__':
    run_tests()
