How to add another sourceSet with a mod in Minecraft Forge (Forge Gradle 3)? - gradle

Question

I have a library made in Forge dev environment, one is in the main source set, containing library code; another is in the testmod (or any other name) source set, containing testing code that needs to be loaded as a Forge mod.
Simply adding
sourceSets {
testmod {
compileClasspath += sourceSets.main.output
runtimeClasspath += sourceSets.main.output
java {
srcDir "src/testmod/java"
}
resources {
srcDir "src/testmod/resources"
}
}
}
into my build.gradle, Forge doesn't scan the source set and therefore doesn't load my mod. How can I make Forge load my mod?
Note that my mod is in Forge 1.14.4, and this should apply to all versions with Forge Gradle 3.

Answer 1

Forge loads mod through the mods declared in the minecraft/run section. You will need to add the following lines to make Forge scan the testmod source set for mods.
minecraft {
// ...
runs {
client {
// ...
mods {
mainmodid {
source sourceSets.main
}
testmodid {
source sourceSets.testmod
}
}
}
server {
// ...
mods {
mainmodid {
source sourceSets.main
}
testmodid {
source sourceSets.testmod
}
}
}
}
}
Replace mainmodid and testmodid with your own modid's. The mainmodid should be included in MDK as examplemod.
Although this does make Forge load your classes, it won't be able to find your mods.toml properly though (depends on ForgeGradle version). If you run into loading errors saying test mod isn't found in mods.toml, add the following snippet too
processResources {
from(sourceSets.testmod.resources.srcDirs) {
include "META_INF/mods.toml"
}
}
Also simply adding the source set testmod won't add Forge and Minecraft as a dependency for it automatically. You will also to have add
configurations {
testmodCompile.extendsFrom(compile)
testmodCompileOnly.extendsFrom(compileOnly)
testmodRuntimeOnly.extendsFrom(runtimeOnly)
}
to make Gradle add Forge and Minecraft (the testmod in testmodCompile is the source set name, see Gradle documentation).