scala - 异步断言未在 scalatest 中触发

Question

我正在尝试编写一个测试来检查是否设置了正确的数据库，但断言永远不会触发，并且一切都成功结束(即使它应该失败):

import anorm._
import org.scalatestplus.play._
import play.api.db.DB

class Housekeeping extends PlaySpec with OneServerPerSuite {

    // Make sure the test database is loaded
    "test connection to test database" in {

        DB.withConnection { implicit connection =>
            SQL("SELECT * FROM accounts WHERE ID = 1").withResult(res => {
                val row = res.head.row
                val name = row.asMap("accounts.name")
                println(name)               // Prints to console
                name mustEqual "this should fail"
                println("HERE")             // Never prints to console
            })
        }
    }
}

控制台:

[info] Housekeeping:
[info] - application - Creating Pool for datasource 'default'
tyler
[info] - test connection to test database
[info] - application - Shutting down connection pool.

---

我不确定为什么什么都没有发生，因为我从数据库中得到了正确的名称。我找不到任何关于执行异步测试的文档，我认为这可能是问题的一部分。

Answer 1

类似于 this可以帮助:

import org.scalatest._
import concurrent.AsyncAssertions

import anorm._
import org.scalatestplus.play._
import play.api.db.DB

class Housekeeping extends PlaySpec with OneServerPerSuite with AsyncAssertions {

    // Make sure the test database is loaded
    "test connection to test database" in {
        val w = new Waiter
        DB.withConnection { implicit connection =>
            SQL("SELECT * FROM accounts WHERE ID = 1").withResult(res => {
                val row = res.head.row
                val name = row.asMap("accounts.name")
                println(name)               // Prints to console
                w { name mustEqual "this should fail" }
                w.dismiss()
                println("HERE")            
            })
        }
        w.await()
    }
}

您的问题是 scalatest 没有收到 mustEqual 引发的异常，因为它是异步抛出的。

实际上 Waiter 是一种围绕 Promise 的包装器(所以你必须执行 dismiss() 才能完成它)和 w.await() 只是等待它并将异常从 w{...} 重定向到 scalatest 的线程。