android - How can I provide a "fakes" product flavor without also specifying a "real" (default) product flavor? -

i want provide build variant fake implementation of interfaces provided module. can use productflavors achieve this

android {   flavordimensions "realorfake"    productflavors {       fakes {...}       real {...}   } } 

this generates 4 build variants

• fakesdebug
• fakesrelease
• realassemble
• realrelease

however want provide default configuration, , optional fakes configuration (i don't want define real product flavor. 4 build variants should be:

• fakesdebug
• fakesrelease
• debug
• release

is possible? or have provide real product flavor , utilize matchingfallbacks? want avoid every downstream module having specify real flavor. i'd want compile use upstream's real product flavor, , testcompile use upstream's fakes product flavor.

note: using android gradle plugin 3.0