Using flatDirs should be avoided because it doesn't support any meta-data formats

Inside your build.gradle file,
add following piece of code in android block:

android { ..
  sourceSets {
        main {
            jniLibs.srcDirs = ['libs']
        }
    }
}

and add dependency as:

implementation (files("libs/test_name.aar"))

delete following block:

repositories {
    flatDir {
        dirs 'libs'
    }
}

Use the LIBS directory. Remove that code and replace it by the following in the module.gradle.

android {
    sourceSets {
        main {
            jniLibs.srcDirs = ['libs']
        }
    }
}

You can add the aar like this, without the need to use flatDir :

dependencies {
    implementation files('/path/to/dir/something_local.aar')
}