fuzztest-rust: Add GitHub Actions workflow for Cargo tests

- Add .github/workflows/cargo_test.yml to run cargo test across the workspace in OSS.
- Build Centipede static library and binary with Bazel to satisfy engine-ffi linking.
- Configure Bazel cache restoration with fallback to centipede default cache.

PiperOrigin-RevId: 964774535

.github/workflows/cargo_test.yml

diff --git a/.github/workflows/cargo_test.yml b/.github/workflows/cargo_test.yml
new file mode 100644
index 0000000..36524fc
--- /dev/null
+++ b/.github/workflows/cargo_test.yml
@@ -0,0 +1,81 @@
+# Copyright 2026 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+name: Cargo Test
+
+on:
+  push:
+    branches:
+      - main
+  pull_request:
+  schedule:
+    # Triggered nightly at 8:00 AM UTC to reset the Bazel & Cargo caches.
+    - cron: '0 8 * * *'
+  workflow_dispatch:
+
+env:
+  CARGO_TERM_COLOR: always
+
+permissions:
+  contents: read
+
+jobs:
+  run_cargo_tests:
+    name: Run Cargo tests
+    runs-on: ubuntu-22.04
+    timeout-minutes: 60
+    permissions:
+      contents: read
+    steps:
+      - name: Disable core dumping and piping due to slowness
+        run: |
+          sudo sysctl -w kernel.core_pattern=""
+
+      - name: Checkout repository
+        uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683  # v4.2.2
+
+      - name: Install system dependencies
+        run: |
+          sudo apt-get update && sudo apt-get install -yq \
+            clang
+
+      - name: Setup Rust toolchain
+        uses: actions-rust-lang/setup-rust-toolchain@1fbea72663f6d4c03efaab13560c8a24cfd2a7cc  # v1.9.0
+        with:
+          toolchain: nightly
+
+      - name: Restore Bazel cache
+        uses: actions/cache/restore@0057852bfaa89a56745cba8c7296529d2fc39830  # v4.3.0
+        with:
+          path: "~/.cache/bazel"
+          key: bazel-centipede-cache-cargo-test
+          restore-keys: bazel-centipede-cache-cargo-test-
+
+      - name: Build Centipede static library and binary with Bazel
+        run: |
+          bazel build -c opt //centipede:centipede_engine_static //centipede:centipede
+
+      - name: Run Cargo workspace tests
+        env:
+          FUZZTEST_LIB_PATH: ${{ github.workspace }}/bazel-bin/centipede
+          CENTIPEDE_BINARY_PATH: ${{ github.workspace }}/bazel-bin/centipede/centipede
+        run: |
+          cargo test --locked --workspace --no-fail-fast -- --test-threads=1
+
+      - name: Save Bazel cache based on main
+        if: github.ref == 'refs/heads/main'
+        uses: actions/cache/save@0057852bfaa89a56745cba8c7296529d2fc39830  # v4.3.0
+        with:
+          path: "~/.cache/bazel"
+          key: bazel-centipede-cache-cargo-test-${{ github.run_id }}

rust/Cargo.toml

diff --git a/rust/Cargo.toml b/rust/Cargo.toml
index 7c3cbae..2a7116c 100644
--- a/rust/Cargo.toml
+++ b/rust/Cargo.toml
@@ -44,9 +44,6 @@
 version = "1.0.103"
 features = ["diff"]
 
-[dev-dependencies.googletest]
-version = "0.14.2"
-
 [profile.fuzztest]
 inherits = 'release'
 panic = 'abort'

rust/src/options.rs

diff --git a/rust/src/options.rs b/rust/src/options.rs
index 0879705..f7da7ee 100644
--- a/rust/src/options.rs
+++ b/rust/src/options.rs
@@ -269,7 +269,7 @@
     /// write to restricted output files, or trigger other harness-specific behavior that
     /// interferes with fuzzing.
     fn default_env_diff() -> Vec<String> {
-        let mut env_diff = vec![
+            let env_diff = vec![
             "-TEST_DIAGNOSTICS_OUTPUT_DIR".to_string(),
             "-TEST_INFRASTRUCTURE_FAILURE_FILE".to_string(),
             "-TEST_LOGSPLITTER_OUTPUT_FILE".to_string(),