mock　WxPayUnifiedOrderResult出現錯誤

java.lang.NullPointerException
	at com.github.binarywang.wxpay.bean.result.BaseWxPayResult.getXmlDoc(BaseWxPayResult.java:180)
	at com.github.binarywang.wxpay.bean.result.BaseWxPayResult.hashCode(BaseWxPayResult.java:41)
	at com.github.binarywang.wxpay.bean.result.WxPayUnifiedOrderResult.hashCode(WxPayUnifiedOrderResult.java:17)
	at io.mockk.EqMatcher.hashCode(Matchers.kt)
	at java.util.AbstractList.hashCode(AbstractList.java:541)
	at io.mockk.InvocationMatcher.hashCode(API.kt:3810)
	at java.util.HashMap.hash(HashMap.java:338)
	at java.util.HashMap.get(HashMap.java:556)
	at java.util.Collections$SynchronizedMap.get(Collections.java:2584)
	at io.mockk.impl.InternalPlatform.customComputeIfAbsent(InternalPlatform.kt:39)
	at io.mockk.impl.stub.MockKStub$childMockK$$inlined$synchronized$lambda$1.invoke(MockKStub.kt:192)
	at io.mockk.impl.recording.CommonCallRecorder.safeExec(CommonCallRecorder.kt:72)
	at io.mockk.impl.log.SafeToString.exec(SafeToString.kt:10)
	at io.mockk.impl.stub.MockKStub.childMockK(MockKStub.kt:191)
	at io.mockk.impl.recording.PermanentMocker.permamentize(PermanentMocker.kt:48)
	at io.mockk.impl.recording.PermanentMocker.mock(PermanentMocker.kt:24)
	at io.mockk.impl.recording.states.RecordingState.mockPermanently(RecordingState.kt:121)
	at io.mockk.impl.recording.states.RecordingState.round(RecordingState.kt:33)
	at io.mockk.impl.recording.CommonCallRecorder.round(CommonCallRecorder.kt:50)
	at io.mockk.impl.eval.RecordedBlockEvaluator.record(RecordedBlockEvaluator.kt:59)
	at io.mockk.impl.eval.EveryBlockEvaluator.every(EveryBlockEvaluator.kt:30)
	at io.mockk.MockKDsl.internalEvery(API.kt:92)
	at io.mockk.MockKKt.every(MockK.kt:104)