def list_tests(arn=None, nextToken=None):
    """
    Gets information about tests.
    See also: AWS API Documentation
    
    Examples
    The following example returns information about tests, given a specific Device Farm project.
    Expected Output:
    
    :example: response = client.list_tests(
        arn='string',
        nextToken='string'
    )
    
    
    :type arn: string
    :param arn: [REQUIRED]
            The tests' ARNs.
            

    :type nextToken: string
    :param nextToken: An identifier that was returned from the previous call to this operation, which can be used to return the next set of items in the list.

    :rtype: dict
    :return: {
        'tests': [
            {
                'arn': 'string',
                'name': 'string',
                'type': 'BUILTIN_FUZZ'|'BUILTIN_EXPLORER'|'APPIUM_JAVA_JUNIT'|'APPIUM_JAVA_TESTNG'|'APPIUM_PYTHON'|'APPIUM_WEB_JAVA_JUNIT'|'APPIUM_WEB_JAVA_TESTNG'|'APPIUM_WEB_PYTHON'|'CALABASH'|'INSTRUMENTATION'|'UIAUTOMATION'|'UIAUTOMATOR'|'XCTEST'|'XCTEST_UI',
                'created': datetime(2015, 1, 1),
                'status': 'PENDING'|'PENDING_CONCURRENCY'|'PENDING_DEVICE'|'PROCESSING'|'SCHEDULING'|'PREPARING'|'RUNNING'|'COMPLETED'|'STOPPING',
                'result': 'PENDING'|'PASSED'|'WARNED'|'FAILED'|'SKIPPED'|'ERRORED'|'STOPPED',
                'started': datetime(2015, 1, 1),
                'stopped': datetime(2015, 1, 1),
                'counters': {
                    'total': 123,
                    'passed': 123,
                    'failed': 123,
                    'warned': 123,
                    'errored': 123,
                    'stopped': 123,
                    'skipped': 123
                },
                'message': 'string',
                'deviceMinutes': {
                    'total': 123.0,
                    'metered': 123.0,
                    'unmetered': 123.0
                }
            },
        ],
        'nextToken': 'string'
    }
    
    
    :returns: 
    BUILTIN_FUZZ: The built-in fuzz type.
    BUILTIN_EXPLORER: For Android, an app explorer that will traverse an Android app, interacting with it and capturing screenshots at the same time.
    APPIUM_JAVA_JUNIT: The Appium Java JUnit type.
    APPIUM_JAVA_TESTNG: The Appium Java TestNG type.
    APPIUM_PYTHON: The Appium Python type.
    APPIUM_WEB_JAVA_JUNIT: The Appium Java JUnit type for Web apps.
    APPIUM_WEB_JAVA_TESTNG: The Appium Java TestNG type for Web apps.
    APPIUM_WEB_PYTHON: The Appium Python type for Web apps.
    CALABASH: The Calabash type.
    INSTRUMENTATION: The Instrumentation type.
    UIAUTOMATION: The uiautomation type.
    UIAUTOMATOR: The uiautomator type.
    XCTEST: The XCode test type.
    XCTEST_UI: The XCode UI test type.
    
    """
    pass
