Kotlin: junit4.AndroidJUnit4ClassRunner for AndroidJUnit4 could not be loaded

Im getting this error when I try to test my Room DB. Tried with other solutions Ive found here (not many) and nothing seems to solve it.

If it may help, the default test automatically appears when you create your project (ExampleInstrumentedTest) does work.

This is the test file:

package com.example.weathered

import android.content.Context
import androidx.room.Room
import androidx.test.core.app.ApplicationProvider
import androidx.test.ext.junit.runners.AndroidJUnit4
import com.example.weathered.database.CurrentWeatherDao
import com.example.weathered.database.ForecastWeatherDao
import com.example.weathered.database.WeatherDatabase
import com.example.weathered.entities.CurrentWeather
import org.hamcrest.Matchers.equalTo
import org.junit.After

import org.junit.Assert.*
import org.junit.Before
import org.junit.Test
import org.junit.runner.RunWith
import java.io.IOException

@RunWith(AndroidJUnit4::class)
class EntityReadWriteTest {

    private lateinit var currentWeatherDao: CurrentWeatherDao
    private lateinit var forecastWeatherDao: ForecastWeatherDao
    private lateinit var database: WeatherDatabase

    @Before
    fun createDB() {
        val context = ApplicationProvider.getApplicationContext<Context>()
        database = Room.inMemoryDatabaseBuilder(context, WeatherDatabase::class.java).build()
        currentWeatherDao = database.currentWeatherDao()
        forecastWeatherDao = database.forecastWeatherDao()
    }

    @After
    @Throws(IOException::class)
    fun closeDB() {
        database.close()
    }

    @Throws(Exception::class)
    @Test
    suspend fun writeCurrentWeatherAndReadUser() {
        val id = 1
        val currentWeather: CurrentWeather = TestUtil.createCurrentWeather(id).apply { }
        currentWeatherDao.insert(currentWeather)
        assertThat(
            database.currentWeatherDao().get(id).value?.cityName,
            equalTo(currentWeather.cityName)
        )
    }
}

And this is mi gradle file:

apply plugin: 'com.android.application'
apply plugin: 'kotlin-android'
apply plugin: 'kotlin-android-extensions'

android {
    compileSdkVersion 28
    buildToolsVersion "29.0.3"

    defaultConfig {
        applicationId "com.example.weathered"
        minSdkVersion 23
        targetSdkVersion 28
        versionCode 1
        versionName "1.0"

        testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
    }

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

}

dependencies {
    implementation fileTree(dir: 'libs', include: ['*.jar'])
    implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk7:$kotlin_version"
    implementation 'androidx.appcompat:appcompat:1.1.0'
    implementation 'androidx.core:core-ktx:1.2.0'
    implementation 'androidx.constraintlayout:constraintlayout:1.1.3'
    //testImplementation 'junit:junit:4.13'
    androidTestImplementation 'androidx.test.ext:junit:1.1.1'
    androidTestImplementation "androidx.room:room-testing:2.2.4"

    androidTestImplementation 'androidx.test:runner:1.2.0'
    androidTestImplementation 'androidx.test:rules:1.2.0'
    // Optional -- Hamcrest library
    androidTestImplementation 'org.hamcrest:hamcrest-library:1.3'

    implementation 'com.google.code.gson:gson:2.8.6'

    implementation 'com.survivingwithandroid:weatherlib:1.6.0'
    implementation 'com.survivingwithandroid:weatherlib_volleyclient:1.6.0'
    implementation 'com.mcxiaoke.volley:library:1.0.6@aar'
    implementation 'androidx.room:room-runtime:2.2.4'
    annotationProcessor 'androidx.room:room-compiler:2.2.4'
}

Thanks in advance.