robolectric/src/main/java/org/robolectric/ConfigMerger.java
@Nullable
  private Config buildPackageConfig(String packageName) {
    return Config.Implementation.fromProperties(getConfigProperties(packageName));
  }
@Nullable
  private Config buildPackageConfig(String packageName) {
    return Config.Implementation.fromProperties(getConfigProperties(packageName));
  }
Generate {@link Config} for the specified package.

More specific packages, test classes, and test method configurations
will override values provided here.

The default implementation uses properties provided by {@link #getConfigProperties(String)}.

The returned object is likely to be reused for many tests.

@param packageName the name of the package, or empty string ({@code ""}) for the top level package
@return {@link Config} object for the specified package
@since 3.2