CODEWITHSUNDEEP
kotlinunit-testingenvironment-variablestddmockk
echen
echen

Reputation: 2072

MockK the System.getenv

The goal is to test a method that calls System.getenv internally. I'd like to make this method produce a predefined result.

Tried:

mockkStatic(System::class)
every {
    System.getenv(any())
} answers {
    when {
        firstArg() as String == "clientId" -> "aaa"
        firstArg() as String == "clientSecret" -> "bbb"
        else -> throw IllegalArgumentException("something went wrong")
    }
}
mockkStatic(System::class)

This appears to have sent the JVM into a bit of tipsy:

Exception in thread "main" java.lang.StackOverflowError
Exception: java.lang.StackOverflowError thrown from the UncaughtExceptionHandler in thread "main"

How does one test a method like this? (as you can imagine, a lot of code uses environment variables)

Upvotes: 4

Views: 3678

Answers (1)

Mahozad
Mahozad

Reputation: 24522

How about using the System Stubs library?

testImplementation("uk.org.webcompere:system-stubs-core:2.1.7") // Main artifact
testImplementation("uk.org.webcompere:system-stubs-jupiter:2.1.7") // For JUnit 5

Pay attention to the @ExtendWith(SystemStubsExtension::class):

@ExtendWith(SystemStubsExtension::class)
class ExampleTests {

    @SystemStub
    val systemProperties = SystemProperties()

    @SystemStub
    val environmentVariables = EnvironmentVariables()

    @Test
    fun `Example test`() {
        systemProperties.set("os.name", "windows")
        environmentVariables.set("MY_VARIABLE", "bunny")
        // ...
    }
}

Upvotes: 0

Related Questions