BuildConfigField mock for unit test in Kotlin

Question

I'm trying to cover as much as possible a Kotlin Android library and I'm encountering an issue about custom BuildConfig variable, better known as buildConfigField.

I would like to mock this variable to test both true and false values.

Extract from Gradle file :

android {
    defaultConfig {
        buildConfigField "boolean", "ENABLE_LOG", "false"
    }
    flavorDimensions "log"
    productFlavors {
        loggable {
            buildConfigField "boolean", "ENABLE_LOG", "true"
            dimension "log"
        }
        notloggable {
            dimension "log"
        }
    }
}

Extract of the Kotlin function to be tested :

fun buildClient(): MyClient {
    var myClientBuilder : MyClient.Builder = MyClient.Builder();

    if (BuildConfig.ENABLE_LOG) {
        val interceptor = LoggingInterceptor();
        interceptor.setLevel(LoggingInterceptor.Level.ALL);
        myClientBuilder.addInterceptor(interceptor);
    }

    return myClientBuilder.build()
}

Unit test :

@Test
fun buildClient_enableLog_oneInterceptor() {
    // GIVEN
    Mockito.mock(BuildConfig::class.java)
    Mockito.doReturn(true).`when`(BuildConfig.ENABLE_LOG)

    // WHEN
    val myClient = myService!!.buildClient()

    // THEN
    assertNotNull(myClient)
    assertNotNull(myClient.interceptors())
    assertEquals(1, myClient.interceptors().size)
}

I tried different things and it never works. If someone have already done this work, it can help me a lot (and others I guess).

Thanks

Why don't you send the variable `BuildConfig.ENABLE_LOG` as an argument to your function? That way you can mock it for testing by calling `buildClient(enableLog: Boolean)` ? Or pull it to the class level by sending it in the constuctor of the class containing the function? OR use dependency injection to inject the variable into your class? — Usama K. Zafar, Sep 05 '18 at 10:38
I found a solution in the documentation : https://developer.android.com/studio/test/ You can check code at : https://github.com/BapNesS/android-unittests-demo — BapNesS, Sep 06 '18 at 12:24
@BaptisteCarlier Can you please write that as an answer with some details? It's hard to follow the link to your code as there are a lot of other classes there that might need to check for the answer to this specific question. Just a simple snippet should do the job I think. — Reaz Murshed, Oct 09 '19 at 20:25

score 5 · Answer 1 · edited Mar 08 '21 at 09:01

5

ReflectionHelpers.setStaticField(BuildConfig::class.java, "ENABLE_LOG", true)

edited Mar 08 '21 at 09:01

Tomerikoo

18,379
16
47
61

answered Mar 08 '21 at 09:00

Dev Soni

489
4
12

2

From where can I import ReflectionHelpers? – Michał Jabłoński Oct 20 '21 at 16:04
2

"ReflectionHelpers" is part of the Robolectric eco system. – arkascha Jul 13 '22 at 06:53
1

This doesn't work for me. The config property doesn't change. – ciaranodc Dec 15 '22 at 11:51
@ciaranodc - were you able to get this to work? – dazza5000 Apr 05 '23 at 20:08
Its better to create a wrapper upon BuildConfig and get the value from that class you can mock it or inject anywhere . – Dev Soni Apr 06 '23 at 11:27
getting exception using this method. `java.lang.RuntimeException: java.lang.IllegalAccessException: Can not set static final java.lang.Boolean field ca.manulife.MobileBanking.BuildConfig.AML_ENABLED to java.lang.Boolean` – Arpit Patel Jul 05 '23 at 12:57

Sahil · Answer 2 · 2021-01-14T09:25:14.693

0

By default, all tests run against the debug build type. You can change this to another build type by using the testBuildType property in your module-level build.gradle file. For example, if you want to run your tests against your "staging" build type, edit the file as shown in the following snippet.

android { ... testBuildType "staging" } but this is causing other options to fail

edited Jan 14 '21 at 09:25

answered Jan 14 '21 at 09:14

Sahil

25
7

score 0 · Answer 3 · answered Aug 16 '22 at 21:43

Little late to the party but this is how you should test any thing related to BuildConfig file. BuildConfig.java is generated for each variant of your app. In your case you have atleast 4 variants.

LoggableDebug
LoggableRelease
NotloggableDebug
NotloggableRelease

ENABLE_LOG will be false for options 3 and 4. If you want to Unit test this, I recommend writing UnitTest in src/testNotLoggable/java/com/.../TestFile.java.

In that TestFile.java your BuildConfig.ENABLE_LOG should be false.

You can check BuildConfig.java file for each variant under /build/source/buildConfig/flavorname/debug/com/project/../BuildConfig.java

BuildConfigField mock for unit test in Kotlin

Extract from Gradle file :

Extract of the Kotlin function to be tested :

Unit test :

3 Answers3

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