Copying gomock definition and tests from rules_go (#231)

This PR copies the gomock definition and tests from rules_go with
minimal changes:

* Replacing github.com/golang/mock with go.uber.org/mock
* Replacing `load` statements accordingly
* Setting up a Bazel and a Go module in the "bazel" directory

Note that the Go module uses v0.4.0 of go.uber.org/mock, because the
latest version is no longer compatible with the gomock rule
(bazel-contrib/rules_go#4153). We will update
the rule and mockgen version in subsequent PRs.

This is a first step in addressing #225

.github/workflows/test.yaml

@@ -9,7 +9,7 @@ permissions:
   contents: read
 
 jobs:
-  test:
+  go:
     strategy:
       matrix:
         go-version: [1.22.x, 1.23.x] # oldest version that can build go mock and official supported go versions
@@ -40,10 +40,35 @@ jobs:
         ./ci/test.sh
         ./ci/check_panic_handling.sh
 
-    - name: Run Tests
+    - name: Run Go Tests
       run: |
-        for i in $(find $PWD -name go.mod); do
+        for i in $(find $PWD -name go.mod ! -path "$PWD/bazel/go.mod"); do
           pushd $(dirname $i)
           go test ./...
           popd
         done 
+
+  bazel:
+    strategy:
+      matrix:
+        os:
+          - macos
+          - ubuntu
+    runs-on: ${{ matrix.os }}-latest
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v4
+
+      - name: Setup Bazel
+        uses: bazel-contrib/[email protected]
+        with:
+          # Avoid downloading Bazel every time.
+          bazelisk-cache: true
+          # Store build cache per workflow.
+          disk-cache: ${{ github.workflow }}
+          # Share repository cache between workflows.
+          repository-cache: true
+
+      - name: Run Bazel tests
+        run: |
+          cd bazel && bazel test //...

bazel/.gitignore

@@ -0,0 +1,2 @@
+bazel-*
+MODULE.bazel.lock

bazel/MODULE.bazel

@@ -0,0 +1,16 @@
+module(name = "bazel_gomock")
+
+bazel_dep(name = "bazel_skylib", version = "1.7.1")
+bazel_dep(name = "rules_go", version = "0.51.0", repo_name = "io_bazel_rules_go")
+bazel_dep(name = "gazelle", version = "0.40.0")
+
+go_sdk = use_extension("@io_bazel_rules_go//go:extensions.bzl", "go_sdk")
+
+go_sdk.download(version = "1.23.4")
+
+go_deps = use_extension("@gazelle//:extensions.bzl", "go_deps")
+go_deps.from_file(go_mod = "//:go.mod")
+use_repo(
+    go_deps,
+    "org_uber_go_mock",
+)

bazel/go.mod

@@ -0,0 +1,5 @@
+module go.uber.org/mock/bazel
+
+go 1.23.0
+
+require go.uber.org/mock v0.4.0

bazel/go.sum

@@ -0,0 +1,2 @@
+go.uber.org/mock v0.4.0 h1:VcM4ZOtdbR4f6VXfiOpwpVJDL6lCReaZ6mw31wqh7KU=
+go.uber.org/mock v0.4.0/go.mod h1:a6FSlNadKUHUa9IP5Vyt1zh4fC7uAwxMutEAscFbkZc=

bazel/rules/BUILD.bazel

@@ -0,0 +1,9 @@
+load("@io_bazel_rules_go//go:def.bzl", "go_library")
+
+go_library(
+    name = "rules",
+    srcs = ["tools.go"],
+    importpath = "go.uber.org/mock/bazel/rules",
+    visibility = ["//visibility:public"],
+    deps = ["@org_uber_go_mock//mockgen/model:go_default_library"],
+)