在kotlin单元测试中如何赋值lateinit var

@RunWith(MockitoJUnitRunner::class) class RoundingTest { lateinit var rounding: (Double) -> Double @Before fun initValues(){ rounding(17.25) } @Test fun checkRounding() { rounding(17.25) var rounding = MyRoundingClass.roundValue(Myobject); Assert.assertEquals(17.23, rounding) } } object MyRoundingClass{ fun roundValue(myObject: MyObject): (Double) -> Double { return when (myObject.isrouding?.needed) { ROUND_DOWN -> { value -> roundDown(BigDecimal.valueOf(value)) } else -> // no rounding { value -> value } } } } 

在roundValue方法中，值参数从“我的片段”中的四舍五入（17.25）得到分配，效果很好，但它测试不起作用。 它给了我下面的错误kotlin.UninitializedPropertyAccessException：lateinit属性舍入尚未初始化

 at com.appetizeactivate.android.rounding.RoundingStatergyTest.checkRoundingWithNone(RoundingTest.kt:23) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:498) at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50) at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12) at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47) at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17) at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325) at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:78) at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:57) at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290) at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71) at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288) at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58) at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268) at org.junit.runners.ParentRunner.run(ParentRunner.java:363) at org.mockito.internal.runners.JUnit45AndHigherRunnerImpl.run(JUnit45AndHigherRunnerImpl.java:37) at org.mockito.runners.MockitoJUnitRunner.run(MockitoJUnitRunner.java:62) at org.junit.runner.JUnitCore.run(JUnitCore.java:137) at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:117) at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:42) at com.intellij.rt.execution.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:262) at com.intellij.rt.execution.junit.JUnitStarter.main(JUnitStarter.java:84) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:498) at com.intellij.rt.execution.application.AppMain.main(AppMain.java:147) 

Answer 1

它看起来像你需要改变rounding的类型，并做到这一点

  lateinit var rounding: () -> Double 

并将其分配为

  rounding = { 17.25 } 

然后使用它作为rounding() （介意plarentheses）。