Partial implementation to show ideal location for pw_unit_test overrides

src/test_driver/efr32/BUILD.gn

@@ -19,7 +19,6 @@ import("//build_overrides/pigweed.gni")
 
 import("${build_root}/config/defaults.gni")
 import("${efr32_sdk_build_root}/efr32_sdk.gni")
-import("${efr32_sdk_build_root}/silabs_executable.gni")
 
 import("${chip_root}/examples/common/pigweed/pigweed_rpcs.gni")
 import("${chip_root}/src/platform/device.gni")
@@ -62,9 +61,8 @@ efr32_sdk("sdk") {
   ]
 }
 
-silabs_executable("efr32_device_tests") {
-  output_name = "matter-silabs-device_tests.out"
-
+# This is the test runner.  `pw_test` will dep this for each `silabs_executable` target.
+source_set("efr32_test_main") {
   defines = [ "PW_RPC_ENABLED" ]
   sources = [
     "${chip_root}/examples/common/pigweed/RpcService.cpp",
@@ -83,7 +81,6 @@ silabs_executable("efr32_device_tests") {
     "$dir_pw_unit_test:rpc_service",
     "${chip_root}/config/efr32/lib/pw_rpc:pw_rpc",
     "${chip_root}/examples/common/pigweed:system_rpc_server",
-    "${chip_root}/src:tests",
     "${chip_root}/src/lib",
     "${chip_root}/src/lib/support:pw_tests_wrapper",
     "${chip_root}/src/platform/silabs/provision:provision-headers",
@@ -115,12 +112,12 @@ silabs_executable("efr32_device_tests") {
     "-T" + rebase_path(ldscript, root_build_dir),
     "-Wl,--no-warn-rwx-segment",
   ]
-
-  output_dir = root_out_dir
 }
 
 group("efr32") {
-  deps = [ ":efr32_device_tests" ]
+  deps = [
+    "${chip_root}/src:tests",
+  ]
 }
 
 group("runner") {

src/test_driver/efr32/args.gni

@@ -35,3 +35,7 @@ pw_assert_BACKEND = "$dir_pw_assert_log"
 pw_log_BACKEND = "$dir_pw_log_basic"
 
 pw_unit_test_BACKEND = "$dir_pw_unit_test:light"
+
+pw_unit_test_MAIN = "${chip_root}/src/test_driver/efr32:efr32_test_main"
+pw_unit_test_EXECUTABLE_TARGET_TYPE = "silabs_executable"
+pw_unit_test_EXECUTABLE_TARGET_TYPE_FILE = "${efr32_sdk_build_root}/silabs_executable.gni"