pytest

Test calculation.py with pytest

calculation.py

import os

class Cal(object):
    def add_num_and_double(self, x, y):

        if type(x) is not int or type(y) is not int:
            raise ValueError
        result = x + y
        result *= 2
        return result

    def save(self, dir_path, file_name):
        if not os.path.exists(dir_path):
            os.mkdir(dir_path)
        file_path = os.path.join(dir_path, file_name)
        with open(file_path, 'w') as f:
            f.write('test')

conftest.py

import os
import pytest


#Unique fixture
@pytest.fixture
def csv_file(tmpdir):
    with open(os.path.join(tmpdir, 'test.csv'), 'w+') as c:
        print('before test')
        yield c
        print('after test')


def pytest_addoption(parser):
    parser.addoption('--os-name', default='linux', help='os name')

test_calculation.py

#pip install pytest
import pytest
import calculation
import os

is_release = True
#When pytesting with a function, test at the beginning_wear
#def test_add_num_and_double():
#    cal = calculation.Cal()
#    assert cal.add_num_and_double(1, 1) != 4

#When pytesting in class, add TEST at the beginning
class TestCal(object):

    @classmethod
    def setup_class(cls):
        print('start')
        cls.cal = calculation.Cal()
        cls.test_dir = '/tmp/test_dir'
        cls.test_file_name = 'test.txt'

    def test_save_no_dir(self):
        self.cal.save(self.test_dir, self.test_file_name)
        test_file_path = os.path.join(self.test_dir, self.test_file_name)
        assert os.path.exists(test_file_path) is True

    @classmethod
    def teardown_class(cls):
        print('end')
        del cls.cal
        #Actually write above
        import shutil
        if os.path.exists(cls.test_dir):
            shutil.rmtree(cls.test_dir)

    #Called before the test runs
    def setup_method(self, method):
        print('method={}'.format(method.__name__))
        #self.cal = calculation.Cal()

    #Called after the test
    def teardown_method(self, method):
        print('method={}'.format(method.__name__))
        #del self.cal

    #csv_file is its own fixture
    def test_add_num_and_double(self, csv_file):
        print(csv_file)
        #When fixture is request
        #os_name = request.config.getoption('--os-name')
        #print(os_name)
        #if os_name == 'mac':
        #    print('ls')
        #elif os_name == 'windows':
            #print('dir')

        #cal = calculation.Cal()
        assert self.cal.add_num_and_double(1, 1) == 4

    def test_save(self, tmpdir):
        self.cal.save(tmpdir, self.test_file_name)
        test_file_path = os.path.join(tmpdir, self.test_file_name)
        assert os.path.exists(test_file_path) is True

    #Exception test(Can be skipped)
    #@pytest.mark.skip(reason='skip!')
    @pytest.mark.skipif(is_release==True, reason='skip!')
    def test_add_num_and_double_raise(self):
        with pytest.raises(ValueError):
            #cal = calculation.Cal()
            self.cal.add_num_and_double('1', '1')