问题描述
我想编写一个单元测试.因此,我需要MutableLiveData.我从一个非常基本的安装测试开始,但是无法实例化MutableLiveData对象.运行测试时,我始终为null.我要嘲笑什么吗?有什么建议?
I want to write a unit test. Therefore I need MutableLiveData. I started with a very basic test for setup but I cannot instantiate a MutableLiveData object. I is always null when I run the test. Do I have to mock anything? Any suggestions?
@RunWith(MockitoJUnitRunner.class)
public class DefaultLiveDataTest {
private static final int EXPECTED = 5;
private final MutableLiveData<Integer> underTest = new MutableLiveData<>();
@Test
public void exampleTest() {
underTest.setValue(EXPECTED); //underTest is Null
assertEquals(underTest.getValue().intValue(), EXPECTED);
}
}
java.lang.NullPointerException
at android.arch.core.executor.DefaultTaskExecutor.isMainThread(DefaultTaskExecutor.java:58)
at android.arch.core.executor.ArchTaskExecutor.isMainThread(ArchTaskExecutor.java:116)
at android.arch.lifecycle.LiveData.assertMainThread(LiveData.java:434)
at android.arch.lifecycle.LiveData.setValue(LiveData.java:279)
at android.arch.lifecycle.MutableLiveData.setValue(MutableLiveData.java:33)
at com.mypackage.DefaultLiveDataTest.test_that_live_data_has_default_value(DefaultLiveDataTest.java:22)
build.gradle
build.gradle
apply plugin: 'com.android.application'
android {
compileSdkVersion 27
defaultConfig {
applicationId 'com.mypackage.title'
minSdkVersion 16
targetSdkVersion 27
versionCode 1
versionName '1.0'
testInstrumentationRunner 'android.support.test.runner.AndroidJUnitRunner'
}
testOptions {
unitTests.returnDefaultValues = true
}
dependencies {
implementation fileTree(dir: 'libs', include: ['*.jar'])
implementation 'com.android.support:appcompat-v7:27.1.1'
implementation 'com.android.support:design:27.1.1'
implementation 'com.android.support.constraint:constraint-layout:1.0.2'
implementation 'com.android.support:support-vector-drawable:27.1.1'
implementation 'android.arch.lifecycle:extensions:1.1.1'
implementation 'android.arch.lifecycle:viewmodel:1.1.1'
implementation 'android.arch.lifecycle:livedata:1.1.1'
annotationProcessor 'android.arch.lifecycle:compiler:1.1.1'
testImplementation 'junit:junit:4.12'
testImplementation 'org.mockito:mockito-core:1.10.19'
androidTestImplementation 'com.android.support.test:runner:1.0.1'
androidTestImplementation 'com.android.support.test.espresso:espresso-core:3.0.1'
annotationProcessor 'org.androidannotations:androidannotations:4.4.0'
implementation 'org.androidannotations:androidannotations-api:4.4.0'
compileOnly 'org.projectlombok:lombok:1.16.20'
annotationProcessor 'org.projectlombok:lombok:1.16.20'
}
推荐答案
好像您缺少android.arch.core:core-testing依赖项.
Looks like you are missing the android.arch.core:core-testing dependency.
testImplementation "android.arch.core:core-testing:1.1.1"
这允许您在测试中使用InstantTaskExecutorRule,它将摆脱isMainThread调用.
This allows you to use the InstantTaskExecutorRule in your test, which will get rid of the isMainThread call.
https://developer.android.com/参考/android/arch/core/executor/testing/InstantTaskExecutorRule.html
@Rule
public InstantTaskExecutorRule instantTaskExecutorRule = new InstantTaskExecutorRule();
这篇关于在JUnitTest中MutableLiveData为null的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持!