UI遍历中页面定义和动作事件筛选方法

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背景

在Android UI遍历测试中，除传统的基于monkey的随机性测试外，基于模型的测试在测试覆盖率和可回溯性上表现更好，是目前热门的研究方向。在基于模型的测试中，对UI页面的定义和动作事件的筛选是十分重要而基础的工作。本文将介绍UI页面定义和动作事件筛选的具体方法。

技术实现

本项目使用python。我们可以使用UI Automator来获取UI界面的层次树信息。

01

View Tree

UI页面其实是一种树状结构的数据，称作view tree，其节点是每一个子view。每个子view一般包含’resource_id’、‘scrollable’、‘clickable’、'bounds’等信息，我们可以充分利用这些信息，来对页面进行定义以及动作事件的筛选。

900×539 200 KB

为了便于操作，先将view tree树结构转成list列表形式，并保存子view的index索引等信息。

def get_view_list(view_tree):
    view_tree['parent'] = -1
    view_list = []
    view_tree_to_list(0, view_tree, view_list)
    self.last_acc_event['view_list'] = view_list
    return view_list

def view_tree_to_list(index, view_tree, view_list):
    tree_id = len(view_list)
    view_tree['temp_id'] = tree_id
    bounds = [[-1, -1], [-1, -1]]
    bounds[0][0] = view_tree['bounds'][0]
    bounds[0][1] = view_tree['bounds'][1]
    bounds[1][0] = view_tree['bounds'][2]
    bounds[1][1] = view_tree['bounds'][3]
    width = bounds[1][0] - bounds[0][0]
    height = bounds[1][1] - bounds[0][1]
    view_tree['size'] = "%d*%d" % (width, height)
    view_tree['index'] = index
    view_tree['bounds'] = bounds
    view_list.append(view_tree)
    children_ids = []
    for item in range(len(view_tree['children'])):
        child_tree = view_tree['children'][item]
        child_tree['parent'] = tree_id
        view_tree_to_list(item, child_tree, view_list)
        children_ids.append(child_tree['temp_id'])
    view_tree['children'] = children_ids

02

新页面的定义

def get_state_str(view_list):
    state_str_raw = get_state_str_raw(view_list)
    return md5(state_str_raw)

def get_state_str_raw(view_list):
    view_signatures = set()
    for view in view_list:
        view_signature = get_view_signature(view)
        if view_signature:
            view_signatures.add(view_signature)
    return "%s{%s}" % (self.foreground_activity, ",".join(sorted(view_signatures)))

def get_view_signature(view_dict):
    view_text = view_dict['text']
    if view_text is None or len(view_text) > 50:
        view_text = "None"

    signature = "[class]%s[text]%s[%s,%s,%s,%s]" % \
                (view_dict['class'],
                 view_text,
                 view_dict['clickable'],
                 view_dict['checked'],
                 view_dict['scrollable'],
                 view_dict['long-clickable']
                 )
    return signature

03

动作事件筛选

我们遍历所有的子view，首先去掉’resource_id’为’android:id/navigationBarBackground’、'android:id/statusBarBackground’的导航栏的view，这在遍历测试中是不需要的。但有的app，它的导航栏view的’resource_id’不是这个，那就需要新加入过滤的内容，或者直接通过顶栏的坐标过滤掉导航栏。

def get_possible_input(view_list):
    possible_events = []
    enabled_view_ids = []
    touch_exclude_view_ids = set()
    for view_dict in view_list:
        if view_dict['enabled'] and \
           view_dict['resource_id'] not in \
           ['android:id/navigationBarBackground',
            'android:id/statusBarBackground']:
            enabled_view_ids.append(view_dict['temp_id'])

    for view_id in enabled_view_ids:
        if view_list[view_id]['scrollable']:
            possible_events.append(ScrollEvent(view=views_list[view_id], direction="UP"))
            possible_events.append(ScrollEvent(view=views_list[view_id], direction="DOWN"))
            possible_events.append(ScrollEvent(view=views_list[view_id], direction="LEFT"))
            possible_events.append(ScrollEvent(view=views_list[view_id], direction="RIGHT"))
        elif view_list[view_id]['clickable']:
            possible_events.append(TouchEvent(view=views_list[view_id]))
            touch_exclude_view_ids.add(view_id)
        # elif views_list[view_id]['enabled'] and \
        #     views_list[view_id]['focusable']:
        #     possible_events.append(TouchEvent(view=views_list[view_id]))
    return possible_events


for view_id in enabled_view_ids:
    if views_list[view_id]['scrollable']:
        possible_events.append(ScrollEvent(view=views_list[view_id], direction="UP"))
        # possible_events.append(ScrollEvent(view=views_list[view_id], direction="DOWN"))
        possible_events.append(ScrollEvent(view=views_list[view_id], direction="LEFT"))
        possible_events.append(ScrollEvent(view=views_list[view_id], direction="RIGHT"))

for view_id in enabled_view_ids:
    if views_list[view_id]['clickable']:
        possible_events.append(TouchEvent(view=views_list[view_id]))
        touch_exclude_view_ids.add(view_id)


def filter_possible_input(possible_events,origin_dim=[1080, 1920]):
    filter_events = []
    for event in possible_events:
        # 过滤坐标为负的值
        bounds = event.view["bounds"]
        bounds = [bounds[0][0], bounds[0][1], bounds[1][0], bounds[1][1]]
        x_min = max(0, bounds[0])
        y_min = max(0, bounds[1])
        x_max = min(origin_dim[0], bounds[2])
        y_max = min(origin_dim[1], bounds[3])
        if x_min >= x_max or y_min >= y_max:
            continue
        # 更新bounds坐标点
        event.view["bounds"] = [[x_min,y_min],[x_max,y_max]]

        # 过滤小于5个像素的event
        if (y_max-y_min) < 5:
            pass
        else:
            filter_events.append(event)

    return filter_events

总结

通过对页面的定义和动作事件的筛选，我们可以将不同的页面进行区分，相似的页面归为一类，筛选有效的event事件。在此基础上，我们可以构建图模型，将测试任务变为对有向图的遍历问题，在图模型上应用不同的算法，比如深度优先遍历、启发式搜索、深度学习或者强化学习算法等，对App进行充分的遍历测试。

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