Add proto_build_test rule that tests building the protos defined in the workspace.

proto/BUILD.bazel

@@ -1,12 +1,23 @@
-package(
-    default_visibility = ["//visibility:public"],
-    licenses = ["notice"],  # Apache 2.0
-)
 
-load("@rules_proto//proto:defs.bzl", "proto_library")
+load("@bazel_skylib//rules:build_test.bzl", "build_test")
 load("@com_github_grpc_grpc//bazel:cc_grpc_library.bzl", "cc_grpc_library")
 load("@com_github_grpc_grpc//bazel:python_rules.bzl", "py_grpc_library", "py_proto_library")
 load("@io_bazel_rules_go//proto:def.bzl", "go_proto_library")
+load("@rules_license//rules:license.bzl", "license")
+load("@rules_proto//proto:defs.bzl", "proto_library")
+
+package(
+    default_visibility = ["//visibility:public"],
+    default_applicable_licenses = [":license"],
+)
+
+license(
+    name = "license",
+    license_kinds = ["@rules_license//licenses/generic:notice"],
+    license_text = "LICENSE",
+)
+
+exports_files(["LICENSE"])
 
 proto_library(
     name = "p4types_proto",
@@ -126,3 +137,15 @@ py_grpc_library(
     srcs = [":p4runtime_proto"],
     deps = [":p4runtime_py_proto"],
 )
+
+build_test(
+    name = "proto_build_test",
+    targets = [
+        ":p4data_proto",
+        ":p4info_proto",
+        ":p4runtime_cc_grpc",
+        ":p4runtime_proto",
+        ":p4runtime_py_grpc",
+        ":p4types_proto",
+    ],
+)

proto/LICENSE

@@ -0,0 +1 @@
+../LICENSE

proto/WORKSPACE.bazel

@@ -39,3 +39,6 @@ pip_parse(
 
 load("@grpc_python_dependencies//:requirements.bzl", "install_deps")
 install_deps()
+
+load("@bazel_skylib//:workspace.bzl", "bazel_skylib_workspace")
+bazel_skylib_workspace()

proto/p4runtime_deps.bzl

@@ -69,3 +69,21 @@ def p4runtime_deps():
             strip_prefix = "grpc-1.51.1",
             sha256 = "b55696fb249669744de3e71acc54a9382bea0dce7cd5ba379b356b12b82d4229",
         )
+    if not native.existing_rule("bazel_skylib"):
+        http_archive(
+            name = "bazel_skylib",
+            sha256 = "66ffd9315665bfaafc96b52278f57c7e2dd09f5ede279ea6d39b2be471e7e3aa",
+            urls = [
+                "https://mirror.bazel.build/github.com/bazelbuild/bazel-skylib/releases/download/1.4.2/bazel-skylib-1.4.2.tar.gz",
+                "https://github.com/bazelbuild/bazel-skylib/releases/download/1.4.2/bazel-skylib-1.4.2.tar.gz",
+            ],
+        )
+    if not native.existing_rule("rules_license"):
+        http_archive(
+            name = "rules_license",
+            urls = [
+                "https://mirror.bazel.build/github.com/bazelbuild/rules_license/releases/download/0.0.7/rules_license-0.0.7.tar.gz",
+                "https://github.com/bazelbuild/rules_license/releases/download/0.0.7/rules_license-0.0.7.tar.gz",
+            ],
+            sha256 = "4531deccb913639c30e5c7512a054d5d875698daeb75d8cf90f284375fe7c360",
+        )