Robolectric 测试以检查是否显示 SnackBar? [英] Robolectric test to check if a SnackBar is shown?

问题描述

我在我的应用中调用以下代码:

I am calling the following code in my app:

Snackbar.make(this, R.string.empty_task_message, Snackbar.LENGTH_LONG)
    .show()

在我的 Robolectric 测试中，我如何断言这确实被调用了?

How can I assert that this was indeed called, inside my Robolectric test?

我正在考虑诸如遍历视图层次结构并搜索 Snackbar 实例并检查视图是否可见之类的事情.

I was thinking of something like traversing the view hierarchy and searching for a Snackbar instance and checking if the view is visible.

这看起来像是 Robolectric 中长期存在的问题.

This looks like a long standing problem in Robolectric.

推荐答案

与其创建 ShadowClass 相比，我发现了一个更好(更简单、更简单)的方法:

Rather than creating a ShadowClass I found a much better (simpler and less hacky) way:

/**
 * @return a TextView if a snackbar is shown anywhere in the view hierarchy.
 *
 * NOTE: calling Snackbar.make() does not create a snackbar. Only calling #show() will create it.
 *
 * If the textView is not-null you can check its text.
 */
fun View.findSnackbarTextView(): TextView? {
  val possibleSnackbarContentLayout = findSnackbarLayout()?.getChildAt(0) as? SnackbarContentLayout
  return possibleSnackbarContentLayout
      ?.getChildAt(0) as? TextView
}

private fun View.findSnackbarLayout(): Snackbar.SnackbarLayout? {
  when (this) {
    is Snackbar.SnackbarLayout -> return this
    !is ViewGroup -> return null
  }
  // otherwise traverse the children

  // the compiler needs an explicit assert that `this` is an instance of ViewGroup
  this as ViewGroup

  (0 until childCount).forEach { i ->
    val possibleSnackbarLayout = getChildAt(i).findSnackbarLayout()
    if (possibleSnackbarLayout != null) return possibleSnackbarLayout
  }
  return null
}

用作:

val textView: TextView? = rootView.findSnackbarTextView()
assertThat(textView, `is`(notNullValue()))

上面的代码是kotlin的，你可以用java来实现

The above code is kotlin, you can implement the same in java

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