commit c3bdb8abc4bd72b5f7e9ff8d3e9cfc1f83b9c53d
author Eli Lipsitz <elipsitz@google.com> Mon Jun 13 20:58:02 2022 +0000
committer CQ Bot Account <pigweed-scoped@luci-project-accounts.iam.gserviceaccount.com> Mon Jun 13 23:31:45 2022 +0000
tree 5d8b0918ae70cdf71b47ffc831cf858fdc52ce0c
parent 9a41bfeb2355143d3d2fb3d8f78a9b973ba809f7

pw_unit_test: Require 'light' backend for RPC service

The pw_unit_test RPC service only supports the 'light' backend. If it's
used with another backend such as GoogleTest, there will be misleading
compilation errors and the service won't find any of the tests.

This commit adds a build assertion to check that the correct backend is
in use if the RPC service is used.

Change-Id: I184c7476d9f88432cc98a686f1f4f75acd6b0a58
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/97907
Commit-Queue: Eli Lipsitz <elipsitz@google.com>
Reviewed-by: Wyatt Hepler <hepler@google.com>

pw_unit_test/BUILD.gn

diff --git a/pw_unit_test/BUILD.gn b/pw_unit_test/BUILD.gn
index 451fd62..73d22b0 100644
--- a/pw_unit_test/BUILD.gn
+++ b/pw_unit_test/BUILD.gn
@@ -167,6 +167,20 @@
   sources = [ "logging_main.cc" ]
 }
 
+pw_build_assert("require_light_test_backend") {
+  # TODO(b/233073669): Simplify once pw_unit_test_PUBLIC_DEPS is removed.
+  condition = (pw_unit_test_PUBLIC_DEPS == [] &&
+               pw_unit_test_GOOGLETEST_BACKEND == "$dir_pw_unit_test:light") ||
+              filter_include(pw_unit_test_PUBLIC_DEPS,
+                             [ "$dir_pw_unit_test:light" ]) != []
+
+  message = "The pw_unit_test RPC service only works with the 'light' test " +
+            "backend.\n(pw_unit_test_GOOGLETEST_BACKEND = " +
+            "$pw_unit_test_GOOGLETEST_BACKEND)\n" +
+            "(pw_unit_test_PUBLIC_DEPS = $pw_unit_test_PUBLIC_DEPS)"
+  visibility = [ ":*" ]
+}
+
 pw_source_set("rpc_service") {
   public_configs = [ ":public_include_path" ]
   public_deps = [
@@ -175,7 +189,10 @@
     ":unit_test_proto.raw_rpc",
     "$dir_pw_containers:vector",
   ]
-  deps = [ dir_pw_log ]
+  deps = [
+    ":require_light_test_backend",
+    dir_pw_log,
+  ]
   public = [
     "public/pw_unit_test/internal/rpc_event_handler.h",
     "public/pw_unit_test/unit_test_service.h",

pw_unit_test/docs.rst

diff --git a/pw_unit_test/docs.rst b/pw_unit_test/docs.rst
index 7b1edd2..880a3fa 100644
--- a/pw_unit_test/docs.rst
+++ b/pw_unit_test/docs.rst
@@ -378,7 +378,8 @@
 ``pw_unit_test`` provides an RPC service which runs unit tests on demand and
 streams the results back to the client. The service is defined in
 ``pw_unit_test_proto/unit_test.proto``, and implemented by the GN target
-``$dir_pw_unit_test:rpc_service``.
+``$dir_pw_unit_test:rpc_service``. The RPC service is only compatible with the
+default ``pw_unit_test:light`` backend.
 
 To set up RPC-based unit tests in your application, instantiate a
 ``pw::unit_test::UnitTestService`` and register it with your RPC server.