如何将测试文件夹添加到较旧的Android Studio项目

在将要测试的项目结构添加到Android Studio中的旧版Android项目时，我遇到了一些问题.

I'm having some problems adding the project structure for testing, to an older Android project in Android Studio.

当您在Android Studio中创建新项目时，您将获得从开始创建的用于测试的目录.

When you create a new project in Android Studio, you get the directories for testing created from start.

src/test/java - for unit testing 
src/androidTest/java - for Android/UI testing. 

但是我们的项目没有这些，因为这是我们从Eclipse迁移过来的一个较旧的项目.

But our project didn't have those, since it's an older project we have migrated from Eclipse.

我已经成功地将目录(测试)和java文件夹(test/java)添加到了我们的项目中，以便将Java目录识别为Java目录，因此可以添加新的程序包和Java文件.

I have succesfully added the directory (test) and java folder (test/java) for unit testing to our project, where the java directory is recognized as a java directory, so I can add new packages and java files.

当我在Android Project视图中查看软件包时，它们被列为:

When I look at the packages in the Android Project view, they're listed as:

com.ourcompany.ourapp
com.ourcompany.ourapp (test) - And here I can see my testclasses. 

到目前为止一切都很好.

All good so far.

但是我似乎无法为androidTest添加结构.

But I cannot seem add the structure for androidTest.

如果添加目录androidTest并在其下添加一个名为java的javafolder，则java文件夹将标记为绿色，并且可以添加类和包.但是testpackage没有标记为测试.

If I add the directory androidTest and a javafolder called java under it, the java folder is marked as green, and I can add classes and packages. But the testpackage is not marked as a test.

我在android项目视图中得到此结果.

I get this result in the android project view.

com.ourcompany.ourapp
com.ourcompany.ourapp - And here is the testclass, MainActivityTest.java
com.ourcompany.ourapp (test)

当我添加androidTest/java文件夹时，此行出现在build.gradle文件中:

When I added the androidTest/java folder, this line appeared in the build.gradle file:

android { sourceSets { main { java.srcDirs = ['src/main/java', 'src/androidTest/java/'] } } }

如果我删除该行，则androidTest/java文件夹将不再被识别为javafolder，并且我无法再在其中添加类/包.并且在Android项目视图中，MainActivityTest类不再可见.

If I remove that line, then the androidTest/java folder is no longer recognized as a javafolder, and I cannot add classes/packages there anymore. And in the Android Project View, the MainActivityTest class is no longer visible at all.

要添加androidTest文件夹，将其识别为测试文件夹结构，我缺少什么?

What am I missing, when it comes to adding the androidTest folders, for it to be recognized as a test folder structure?

我需要添加到gradles文件中吗?

Is there something I need to add to the gradles file?

android {
    compileSdkVersion 21
    buildToolsVersion '22.0.1'

    defaultConfig {
        applicationId "com.ourcompany.ourapp"
        minSdkVersion 15
        targetSdkVersion 21
    }

    buildTypes {
        release {
            minifyEnabled true
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-project.txt'
        }
    }

    lintOptions {
        checkReleaseBuilds true
        abortOnError false
    }

    configurations.all {
        resolutionStrategy.force 'com.android.support:support-annotations:22.2.1'
    }

}

dependencies {
    compile 'com.android.support:support-v4:22.1.1'
    compile 'com.android.support:design:22.2.1'
    compile 'com.android.support:appcompat-v7:22.1.1'
    testCompile 'junit:junit:4.12'
    testCompile "org.mockito:mockito-core:1.+"
}

android {
    packagingOptions {
        exclude 'META-INF/DEPENDENCIES.txt'
        exclude 'META-INF/LICENSE.txt'
        exclude 'META-INF/NOTICE.txt'
        exclude 'META-INF/NOTICE'
        exclude 'META-INF/LICENSE'
        exclude 'META-INF/DEPENDENCIES'
        exclude 'META-INF/notice.txt'
        exclude 'META-INF/license.txt'
        exclude 'META-INF/dependencies.txt'
        exclude 'META-INF/LGPL2.1'
    }
}