CONFIG_NVDIMM_TEST_BUILD is not available for thedefaultarchitecture x86.
Result is shown for architecture 64BIT

Build the unit test core

configname: CONFIG_NVDIMM_TEST_BUILD

Linux Kernel Configuration
└─>Device Drivers
└─>NVDIMM (Non-Volatile Memory Device) Support
└─>Build the unit test core
In linux kernel since version 5.1 (release Date: 2019-05-05)  
Build the core of the unit test infrastructure. The result of
this build is non-functional for unit test execution, but it
otherwise helps catch build errors induced by changes to the
core devm_memremap_pages() implementation and other
infrastructure.

depends
CONFIG_COMPILE_TEST
CONFIG_LIBNVDIMM
CONFIG_MODULES
CONFIG_X86_64