import unittest
import configparser
import os

def GetFilteredEnvironment(environment): 

    filtered_environment = {}
    for i in environment:
        print(i)
        if '%' in environment[i]:
            continue
        else:
            filtered_environment[i] = environment[i]
    return filtered_environment

class Test_EnvironmentProcessing(unittest.TestCase):
    def test_ParsingException(self):
        environment_dict = {'TestVar': "%TestValueNotExisting%"}
        config = configparser.ConfigParser(environment_dict)
        config['Test'] = {'TestKey':'Correct'}
        with self.assertRaises(configparser.InterpolationSyntaxError):
            config.items('Test')

    def test_ParsingWorkaround(self):
        environment_dict = {'TestVar': "%TestValueNotExisting%"}
        config = configparser.ConfigParser(GetFilteredEnvironment(environment_dict))
        config['Test'] = {'TestKey':'Correct'}
        test_config = config.items('Test')
        #environment variables will lower case within config parser
        self.assertTrue(('testkey','Correct') in test_config)
        self.assertFalse('TestVar' in test_config)

    def test_CurrentEnvironment(self):
        environment_dict = os.environ
        config = configparser.ConfigParser(GetFilteredEnvironment(environment_dict))
        config['Test'] = {'TestKey':'Correct'}
        test_config = config.items('Test')
        #environment variables will lower case within config parser
        self.assertTrue(('testkey','Correct') in test_config)
        self.assertFalse('TestVar' in test_config)