如何测试返回DataSource.Factory的Dao方法? [英] How to test Dao methods which return DataSource.Factory?

问题描述

在我的应用程序中从 SqliteOpenHelper 转移到 room 之后，我试图为 DAO 类编写测试.

After shifting from SqliteOpenHelper to room in my app, I've trying to write tests for the DAO class.

我的DAO看起来像这样:

My DAO looks something like this:

    @Query("SELECT * FROM cards")
    fun getAllCards(): List<CardData>

    @Insert(onConflict = OnConflictStrategy.REPLACE)
    fun insertCard(vararg cardData: CardData): List<Long>

    @Query("SELECT * FROM cards ORDER BY isRead ASC, id DESC")
    fun getItemList(): DataSource.Factory<Int, CardData>

    @Query("SELECT * FROM cards where instr(title, :query) > 0 ORDER BY isRead ASC, id DESC")
    fun getItemList(query: String): DataSource.Factory<Int, CardData>

    @Query("UPDATE cards set isRead = 1 where title = :title")
    fun markRead(title: String): Int

虽然为 getAllCards ， insertCard 和 markRead 编写测试很简单，但我仍然不确定如何测试返回 DataSource.Factory ，即 getItemList API.

While writing test for getAllCards, insertCard and markRead is trivial, I am still not sure how do I test the apis which return DataSource.Factory, i.e getItemList apis.

在互联网上搜索后，我找不到与此相关的任何内容.

After searching on internet, I couldn't find anything related to this.

有人可以帮忙吗?

推荐答案

这就是我的做法:

val factory = dao.getItemList()
val list = (factory.create() as LimitOffsetDataSource).loadRange(0, 10)

引用CommonsWare

Quoting CommonsWare

如果您使用Room进行分页并且有一个@Dao方法返回一个DataSource.Factory，则生成的代码将使用一个名为LimitOffsetDataSource的内部类来执行SQLite操作并履行PositionalDataSource合同.

If you use paging with Room and have a @Dao method return a DataSource.Factory, the generated code uses an internal class named LimitOffsetDataSource to perform the SQLite operations and fulfill the PositionalDataSource contract.

来源: https://commonsware.com/AndroidArch/previews/paging-beyond-room#head206

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