Not able to import InstantTaskExecutorRule in my 'jUnit' test case even after adding 'core-testing' dependency - Android testing

Question

I am writing test cases for my LoginViewModel. Where I want to perform setValue() operation on my MutableLiveData.

To avoid Method getMainLooper in android.os.Looper not mocked Exception I am trying to add the following Rule in my ViewModel file inside test folder.

@Rule public InstantTaskExecutorRule mInstantTaskExecutorRule = new InstantTaskExecutorRule();

for that, I have added the following dependency:

androidTestImplementation 'android.arch.core:core-testing:1.1.1' as dependency.

But still, I am not able to import the InstantTaskExecutorRule in my LoginViewModelTest file. What could be the issue?

Though it's getting imported in androidTest folder where we write integration or UI test cases! But not in test folder where we write jUnit test cases!

Thank you in advance.

Please refer the build. gradle file:

apply plugin: 'com.android.application'

    android {
    compileSdkVersion 28
    defaultConfig {
    applicationId "com.test.login"
    minSdkVersion 19
    targetSdkVersion 28
    versionCode 2
    versionName "1.1"
    multiDexEnabled true
    testInstrumentationRunner 
    "android.support.test.runner.AndroidJUnitRunner"
}

dataBinding {
    enabled = true
}

testOptions {
    unitTests.returnDefaultValues = true
}

buildTypes {
    release {
        minifyEnabled false
        proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
    }
}

}

dependencies {
implementation fileTree(dir: 'libs', include: ['*.jar'])
def design = "28.0.0"
implementation "com.android.support:appcompat-v7:$design"
implementation "com.android.support:design:$design"
implementation "com.android.support:recyclerview-v7:$design"

implementation 'com.android.support.constraint:constraint-layout:1.1.3'
implementation 'com.android.support:support-v4:28.0.0'
testImplementation 'junit:junit:4.12'
androidTestImplementation 'com.android.support.test:runner:1.0.2'
androidTestImplementation 'com.android.support.test.espresso:espresso-core:3.0.2'

androidTestImplementation 'android.arch.core:core-testing:1.1.1'

implementation 'io.reactivex.rxjava2:rxjava:2.1.9'
implementation 'io.reactivex.rxjava2:rxandroid:2.0.2'
androidTestImplementation 'com.android.support.test:runner:1.0.2'
androidTestImplementation 'com.android.support.test:rules:1.0.2'
androidTestImplementation 'com.squareup.retrofit2:retrofit-mock:2.0.0'
implementation 'com.squareup.okhttp3:mockwebserver:3.8.1'
androidTestImplementation 'com.android.support.test.espresso:espresso-intents:3.0.2'
implementation 'com.jakewharton:butterknife:8.8.1'
annotationProcessor 'com.jakewharton:butterknife-compiler:8.8.1'

def daggerVer = 2.16
implementation "com.google.dagger:dagger:$daggerVer"
annotationProcessor "com.google.dagger:dagger-compiler:$daggerVer"
compileOnly 'javax.annotation:jsr250-api:1.0'
implementation 'javax.inject:javax.inject:1'

implementation 'com.squareup.retrofit2:retrofit:2.4.0'
implementation 'com.squareup.okhttp3:logging-interceptor:3.9.1'
implementation 'com.squareup.retrofit2:converter-gson:2.3.0'

//implementation 'com.google.android.material:material:1.0.0'

def lifeCycle = "1.1.1"
implementation "android.arch.lifecycle:extensions:$lifeCycle"
/*implementation "android.arch.lifecycle:runtime:$lifeCycle"
annotationProcessor "android.arch.lifecycle:compiler:$lifeCycle"*/
implementation "android.arch.persistence.room:runtime:$lifeCycle"
implementation 'com.mikhaellopez:circularimageview:3.2.0'
annotationProcessor 
"android.arch.persistence.room:compiler:$lifeCycle"

implementation 'com.squareup.picasso:picasso:2.71828'
implementation 'com.android.support:multidex:1.0.3'

implementation 'commons-beanutils:commons-beanutils:1.9.3'
implementation 'org.mockito:mockito-core:2.23.4'
androidTestImplementation 'org.mockito:mockito-android:2.18.3'
}