Gradle "dev" configurations?

I am developing a library (JAR) that is meant to be used across many projects. I am using SLF4j for logging, and so I have declared the SLF4J API JAR to be a compile configuration.

When I'm developing this library locally on my machine, I'd like to run tests and see the output from all the SLF4J log statements. Or, outside of a test, it helps to add a temporary main(String[]) method to a random class and test functionality and log output as if the lib was an executable JAR. Since SLF4J's default binding is a No-Op (no output whatsoever), I have been getting by so far by adding the SLF4J Simple binding as a compile configuration dependency while I am developing & testing. Then, before I commit and publish, I simply remove the Simple binding as a dependency (since each developer who uses my lib should be able to select their own binding).

This is hacky and I know Gradle support custom configs, but I have yet to see a coherent example that could act as a guide. Ideally I'd like to define a custom dev configuration so that as a dependency I could have:

dependencies {
    compile 'org.slf4j:slf4j-api:1.7.5'
    dev 'org.slf4j:slf4j-simple:1.7.5' // Only used when running/testing locally
}

...but then ony the SLF4J API JAR gets added to my pom. Any ideas as to how to accomplish this? Perhaps Gradle already has such a concept built into it, or perhaps a custom configuration isn't even the right approach.