Upgrading to Android Gradle Plugin 1.3 fails build due to check failure in Espresso tests

Question

Before upgrading to Android Gradle Plugin 1.3, the custom lint scope was only Android source files.

After I upgraded to 1.3.1, my tests files started getting checked and as a scenario fails my custom lint rule, the build fails.

There is no documentation about this. I read some warnings have become fatal but nothing around test files getting scanned.

Anyone facing such an issue?

EDIT:

top level build.gradle

buildscript {
    repositories {
        mavenCentral()
        maven { url 'http://download.crashlytics.com/maven' }
        maven { url "https://plugins.gradle.org/m2/" }
    }
    dependencies {
        classpath 'com.android.tools.build:gradle:1.3.1'
        classpath 'org.sonarqube.gradle:gradle-sonarqube-plugin:1.0'
    }
}

allprojects {
    repositories {
       flatDir {
           dirs './prebuilt-libs'
       }  
        mavenCentral()
    }
}

task wrapper(type: Wrapper) {
    gradleVersion = '2.4'
}

Error:

HardCoding: Detects HardCoded "abc" string ../../src/androidTest/java/com/xyz/mobile/trips/test.java:108: HardCoding Found. (This is my custom lint rule)

hasExtra(CODE, "abc")