Hello,

If you get the following error when you create a new project in Android Studio, you will fix your error when you take the steps in the pictures respectively.

ERROR: Gradle DSL method not found: 'testImplementation()'
Possible causes:
The project 'My Application' may be using a version of the Android Gradle plug-in that does not contain the method (e.g. 'testCompile' was added in 1.1.0).
Upgrade plugin to version 3.4.0 and sync project

The project 'My Application' may be using a version of Gradle that does not contain the method.
Open Gradle wrapper file

The build file may be missing a Gradle plugin.
Apply Gradle plugin

You can run your application by following the steps below.

testİmplementation 'junit:junit:4.12'
androidTestİmplementation 'com.android.support.test:runner:1.0.2'
androidTestİmplementation 'com.android.support.test.espresso:espresso-core:3.0.2'