scala - 如何在 ScalaTest 中使用 ScriptEngine

Question

下面的测试应该通过，但它没有

class EngineTest extends FunSuite {

  test("engine should not be null") {
    val manager: ScriptEngineManager = new ScriptEngineManager
    val engine: ScriptEngine = manager.getEngineByName("nashorn")
    assert(engine != null)
  }
}

manager.getEngineFactories()似乎是空的。为什么？如何初始化上下文？

Answer 1

您需要将 ClassLoader 显式传递给 ScriptEngineManager 构造函数。如果你不这样做，那么它使用 Thread.currentThread().getContextClassLoader()在 SBT 下运行时设置为奇怪的东西。我们刚传入null在我们的代码中让它工作。也可以传入getClass.getClassLoader :

class EngineTest extends FunSuite {
  test("engine should not be null - null classloader") {
    val manager: ScriptEngineManager = new ScriptEngineManager(null)
    val engine: ScriptEngine = manager.getEngineByName("nashorn")
    assert(engine != null)
  }

  test("engine should not be null - getClass.getClassLoader classloader") {
    val manager: ScriptEngineManager = new ScriptEngineManager(getClass.getClassLoader)
    val engine: ScriptEngine = manager.getEngineByName("nashorn")
    assert(engine != null)
  }
}

这两个测试对我来说都通过了:

[info] EngineTest:
[info] - engine should not be null - null classloader
[info] - engine should not be null - getClass.getClassLoader classloader
[info] Run completed in 186 milliseconds.
[info] Total number of tests run: 2
[info] Suites: completed 1, aborted 0
[info] Tests: succeeded 2, failed 0, canceled 0, ignored 0, pending 0
[info] All tests passed.