Mockito 和 PowerMock - class 大小限制

Question

为了模拟单元测试的数据，我使用了 Mockito。但我看到以下异常。我是否缺少任何设置？

此处使用的 JVM 是 Java HotSpot(TM) 64 位服务器 VM。 1.8

public class TestCreateObj{

  public void getMockData() {       
    TestObj deal = mock(TestObj.class);
    when(deal.getDescription()).thenReturn("HURRAH!!!");

    System.out.println(deal.getDescription());      
}

public static void main(String args[]) {
    new TestCreateObj().getMockData();
}

运行时抛出异常：

Caused by: java.lang.RuntimeException: Class file too large!
    at net.bytebuddy.jar.asm.ClassWriter.toByteArray(Unknown Source)
    at net.bytebuddy.dynamic.scaffold.TypeWriter$Default$ForCreation.create(TypeWriter.java:4108)
    at net.bytebuddy.dynamic.scaffold.TypeWriter$Default.make(TypeWriter.java:1612)
    at net.bytebuddy.dynamic.scaffold.subclass.SubclassDynamicTypeBuilder.make(SubclassDynamicTypeBuilder.java:174)
    at net.bytebuddy.dynamic.scaffold.subclass.SubclassDynamicTypeBuilder.make(SubclassDynamicTypeBuilder.java:155)
    at net.bytebuddy.dynamic.DynamicType$Builder$AbstractBase.make(DynamicType.java:2560)
    at net.bytebuddy.dynamic.DynamicType$Builder$AbstractBase$Delegator.make(DynamicType.java:2662)
    at org.mockito.internal.creation.bytebuddy.SubclassBytecodeGenerator.mockClass(SubclassBytecodeGenerator.java:94)
    at org.mockito.internal.creation.bytebuddy.TypeCachingBytecodeGenerator.call(TypeCachingBytecodeGenerator.java:37)
    at org.mockito.internal.creation.bytebuddy.TypeCachingBytecodeGenerator.call(TypeCachingBytecodeGenerator.java:34)
    at net.bytebuddy.TypeCache.findOrInsert(TypeCache.java:138)
    at net.bytebuddy.TypeCache$WithInlineExpunction.findOrInsert(TypeCache.java:346)
    at net.bytebuddy.TypeCache.findOrInsert(TypeCache.java:161)
    at net.bytebuddy.TypeCache$WithInlineExpunction.findOrInsert(TypeCache.java:355)
    at org.mockito.internal.creation.bytebuddy.TypeCachingBytecodeGenerator.mockClass(TypeCachingBytecodeGenerator.java:32)
    at org.mockito.internal.creation.bytebuddy.SubclassByteBuddyMockMaker.createMockType(SubclassByteBuddyMockMaker.java:71)
    at org.mockito.internal.creation.bytebuddy.SubclassByteBuddyMockMaker.createMock(SubclassByteBuddyMockMaker.java:42)
    at org.mockito.internal.creation.bytebuddy.ByteBuddyMockMaker.createMock(ByteBuddyMockMaker.java:26)
    at org.mockito.internal.util.MockUtil.createMock(MockUtil.java:35)
    at org.mockito.internal.MockitoCore.mock(MockitoCore.java:65)
    at org.mockito.Mockito.mock(Mockito.java:1691)
    at org.mockito.Mockito.mock(Mockito.java:1604)

Answer 1

异常来自 ASM，正如 Holger 在评论中指出的那样，它抱怨常量池过大。这是在已经很大的 class.

上同时应用 Mockito 和 PowerMock 暗示的检测的结果

Java class 文件格式设置了一些限制，例如 class 声明的字段、方法或常量的数量。如果您在 non-generated Java class 中超过此限制，则会产生类似的问题。

为了模拟 class，Mockito 要求 Byte Buddy 添加调度程序方法和合成方法以调用每个超级方法。这有效地将方法数量加倍 class 并且还添加到常量池中。 PowerMock 应用了类似的东西。

如果您已经接近常量限制，那么这些添加最终会将您推向 class 文件所能代表的极限。它通常只发生在你有一个只包含几千个 setter 和 getter 的对象时，结果是你根本无法模拟这个对象，尤其是在 Mockito 和 PowerMock 都处于活动状态的情况下。

Mockito 和 PowerMock - class 大小限制

Mockito & PowerMock - class size limitations

java

unit-testing

mockito

byte-buddy