错误:在Android gradle库模块单元测试中找不到符号

Question

我在的IntelliJ一个测试项目(使用Android Studio的插件)和我试图描述设置单元测试在这里.

运行junit测试时,项目似乎无法在src> main> java下找到我的源代码.以下测试

package io.adaptiv.plzwrk.lib;

import junit.framework.TestCase;
import org.junit.Test;

public class AdaptivTest extends TestCase {

    @Test
    public void testDoStuff() throws Exception {
        assertEquals(42, Adaptiv.doStuff());
    }
}

给出了错误

error: cannot find symbol
        assertEquals(42, Adaptiv.doStuff());
                         ^
  symbol:   variable Adaptiv
  location: class AdaptivTest

我的'测试'课程

package io.adaptiv.plzwrk.lib;

public class Adaptiv {

    public static int doStuff() {
        return 42;
    }

}

我的项目布局看起来像这样

使用settings.gradle

include ':lib'

项目build.gradle文件

// Top-level build file where you can add configuration options common to all sub-projects/modules.

buildscript {
    repositories {
        jcenter()
    }
    dependencies {
        classpath 'com.android.tools.build:gradle:1.1.1'

        // NOTE: Do not place your application dependencies here; they belong
        // in the individual module build.gradle files
    }
}

allprojects {
    repositories {
        jcenter()
    }
}

lib目录下的build.gradle

buildscript {
    repositories {
        jcenter()
    }
    dependencies {
        classpath 'com.android.tools.build:gradle:1.1.1'
    }
}
apply plugin: 'com.android.library'

repositories {
    jcenter()
}

android {
    compileSdkVersion 22
    buildToolsVersion "22.0.1"

    defaultConfig {
        minSdkVersion 9
        targetSdkVersion 22
        versionCode 1
        versionName "1.0"
    }

    compileOptions {
        sourceCompatibility JavaVersion.VERSION_1_6
        targetCompatibility JavaVersion.VERSION_1_6
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }
}

dependencies {
    testCompile 'junit:junit:4.12'
    testCompile "org.mockito:mockito-core:1.9.5"
}