title: Could not find method testImplementation() for arguments [junit:junit:4.12]
body: <pre><code>dependencies {
      implementation fileTree(dir: 'libs', include: ['*.jar'])
  
      implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk7:$kotlin_version"
      implementation 'com.android.support:appcompat-v7:28.0.0'
      implementation 'android.arch.navigation:navigation-fragment:1.0.0-alpha06'
      implementation 'android.arch.navigation:navigation-ui:1.0.0-alpha06'
      implementation 'android.arch.navigation:navigation-fragment-ktx:1.0.0-alpha06'
      implementation 'android.arch.navigation:navigation-ui-ktx:1.0.0-alpha06'
      implementation 'com.android.support:design:28.0.0'
      implementation 'com.android.support.constraint:constraint-layout:1.1.3'
      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'
  }
  </code></pre>
  
  <p>This is my build.gradle file and I tried many ways but I can't fix this, when I start Android Studio and gradle starts build the project Android Studio throw this error
  how can I fix it?( I am new in Android)</p>
  
  <p>Could not find method <code>testImplementation()</code> for arguments <code>[junit:junit:4.12]</code> on object of type <code>org.gradle.api.internal.artifacts.dsl.dependencies.DefaultDependencyHandler.</code> </p>