Firstly I did not have androidTest Package in my App, So I created using Run-> Record Espresso Test, So it Created an androidTest package. But Getting this Exception in Logcat while running an Instrumented test. I have Gone through lot of solutions on Stackoverflow and Searched a lot on Google, Nothing works as of now.

E/AndroidRuntime: FATAL EXCEPTION: Instr: androidx.test.runner.AndroidJUnitRunner
        java.lang.NoClassDefFoundError: Failed resolution of: Landroidx/test/platform/io/FileTestStorage;
            at androidx.test.runner.AndroidJUnitRunner.registerTestStorage(AndroidJUnitRunner.java:660)
            at androidx.test.runner.AndroidJUnitRunner.onStart(AndroidJUnitRunner.java:432)
            at android.app.Instrumentation$InstrumentationThread.run(Instrumentation.java:2145)
         Caused by: java.lang.ClassNotFoundException: Didn't find class "androidx.test.platform.io.FileTestStorage" on path: DexPathList[[zip file "/system/framework/android.test.runner.jar", zip file "/system/framework/android.test.mock.jar", zip file "/data/app/net.one97.paytm.test-jZXGpy2zE0ToMIAtdjZZ_w==/base.apk", zip file "/data/app/net.one97.paytm-BEX-7xHHgkWWpGzITJCpTA==/base.apk"],nativeLibraryDirectories=[/data/app/net.one97.paytm.test-jZXGpy2zE0ToMIAtdjZZ_w==/lib/x86, /data/app/net.one97.paytm-BEX-7xHHgkWWpGzITJCpTA==/lib/x86, /data/app/net.one97.paytm.test-jZXGpy2zE0ToMIAtdjZZ_w==/base.apk!/lib/x86, /data/app/net.one97.paytm-BEX-7xHHgkWWpGzITJCpTA==/base.apk!/lib/x86, /system/lib]]
            at dalvik.system.BaseDexClassLoader.findClass(BaseDexClassLoader.java:134)
            at java.lang.ClassLoader.loadClass(ClassLoader.java:379)
            at java.lang.ClassLoader.loadClass(ClassLoader.java:312)
            at androidx.test.runner.AndroidJUnitRunner.registerTestStorage(AndroidJUnitRunner.java:660) 
            at androidx.test.runner.AndroidJUnitRunner.onStart(AndroidJUnitRunner.java:432) 
            at android.app.Instrumentation$InstrumentationThread.run(Instrumentation.java:2145) 

Here is my code.

import androidx.test.ext.junit.runners.AndroidJUnit4
import androidx.test.filters.SmallTest
import org.junit.Assert.assertEquals
import org.junit.Test
import org.junit.runner.RunWith

@SmallTest
@RunWith(AndroidJUnit4::class)
class MainActivityTest {

    @Test
    fun mainActivityTest() {
        assertEquals(2, 1+1)
    }
}

And build.gradle is

apply plugin: 'com.android.application'
apply plugin: 'kotlin-android'
apply plugin: 'kotlin-android-extensions'
apply plugin: 'com.google.gms.google-services'
apply plugin: 'com.google.firebase.firebase-perf'
apply plugin: 'com.google.firebase.crashlytics'

android {
    compileSdkVersion 30
    buildToolsVersion "29.0.3"
    defaultConfig {
        applicationId "****"
        minSdkVersion 24
        targetSdkVersion 30
        versionCode 1
        versionName "10.0.0"
        testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
        multiDexEnabled true

    }

    dexOptions {
        preDexLibraries = false
        javaMaxHeapSize "4g"
        keepRuntimeAnnotatedClasses false
    }
       
    compileOptions {
        sourceCompatibility = '1.8'
        targetCompatibility = '1.8'
    }

    testOptions {
        unitTests {
            includeAndroidResources true
            returnDefaultValues = true
        }
    }

    kotlinOptions {
        jvmTarget = '1.8'
    }

}

repositories {
    google()
    mavenCentral()
    maven { url "https://artifactory.paytm.in/libs-release-local"}
    maven { url 'https://maven.google.com' }
    maven {url "https://midgar.bintray.com/Pai-Network" }
}

buildscript {
    repositories {
        jcenter()
        mavenCentral()
        maven { url 'https://maven.fabric.io/public' }
        maven { url "https://artifactory.paytm.in/libs-release-local"}
        maven { url 'https://maven.google.com' }
        maven {url "https://midgar.bintray.com/Pai-Network" }
    }

}


dependencies {

    implementation fileTree(dir: 'libs', include: ['*.jar'])
    implementation "androidx.appcompat:appcompat:1.2.0"
    implementation 'androidx.constraintlayout:constraintlayout:1.1.3'
    implementation project(path: ':**')
    
    implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk7:$kotlin_version"
    implementation project(path: ':chuck_library')
    implementation project(path: ':appmanager')
    implementation('com.crashlytics.sdk.android:crashlytics:2.10.1@aar') {
        transitive = true
    }




    implementation 'androidx.core:core-ktx:1.4.0'
    testImplementation 'junit:junit:4.12'
    androidTestImplementation 'junit:junit:4.12'
    androidTestImplementation 'androidx.test.ext:junit:1.1.1'
    androidTestImplementation 'androidx.test.espresso:espresso-core:3.5.0-alpha04'

    androidTestImplementation 'androidx.test:core:1.4.0'
    testImplementation 'androidx.test.ext:junit-ktx:1.1.3'
    testImplementation 'org.robolectric:robolectric:4.4'
    testImplementation 'androidx.test.ext:truth:1.4.0'
    testImplementation 'com.google.truth:truth:1.0'
    testImplementation 'org.mockito:mockito-core:3.3.3'
    androidTestImplementation 'androidx.test:runner:1.4.0'
    androidTestImplementation 'androidx.test:rules:1.4.0'
    androidTestImplementation 'com.google.truth:truth:1.0'

    testImplementation "androidx.test:monitor:1.4.0"
    testImplementation 'androidx.test:runner:1.4.0'

}

And On the test results Window. It Shows this