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Power Assert for Android

Power Assert is a language extension which adds extra information when assertions fail. This feature has been invented in Groovy and being spread around other programming languages, and is becoming a fundamental feature for debugging and testing, especially in unit tests: you no longer need to learn a bunch of test matchers such as assertEquals().

This is a Gradle plugin to provide Android with power asserts by modifying Java class files in compilation phases. To use power assert, all you have to do is to depend on android-power-assert-plugin and apply android-power-assert plugin in build.gradle, which automatically enables assert statements unless you makes release build. Thus you can use assert statements both in applications and unit tests.

Usage

This plugin uses assert statements in Java by applying this plugin in build.gradle.

// in the root build.gradle
buildscript {
    repositories {
        mavenCentral() // or jcenter()
    }
    dependencies {
        classpath 'com.android.tools.build:gradle:1.5.2'
        classpath 'com.github.gfx.android.powerassert:plugin:1.5.2'
    }
}

// in a build.gradle of a module
apply plugin: 'android'
apply plugin: 'com.github.gfx.android.powerassert'

Then, use assert in your program:

// in example's MainActivity.java
void onButton2Click() {
    assert findViewById(android.R.id.list).getVisibility() == View.VISIBLE;
}

This shows the following output when findViewById() returns null:

java.lang.NullPointerException:
25:     void onButton2Click() {
26>         assert findViewById(android.R.id.list).getVisibility() == View.VISIBLE;
26:     }
com.github.gfx.powerassert.example.MainActivity.findViewById()=<null>
(...stacktrace...)

Logging

POWERASSERT_VERBOSE=1 shows debug logs including how the plugin spends time in bytecode modification.

POWERASSERT_VERBOSE=2 shows all the extra source code so it might be useful to debug this plugin.

Compatibility

The minor version of this plugin should match with the minor version of Android Gradle Plugin.

That is, android-power-assert-plugin v0.10.x is compatible with Android Gradle Plugin v0.10.x, as well as android-power-assert-plugin v1.1.x is compatible with Android Gradle Plugin v1.1.x.

Author And License