Add fuzz testing for router and OpenAPI (#166)

* added fuzz tests

* fuzzing + gitignore polishing

* made clippy happy

* adjusted openapi fuzzing

Author: RomanEmreis

.github/workflows/fuzz.yml

@@ -0,0 +1,61 @@
+name: Fuzz
+
+on:
+  pull_request:
+    branches: ["main"]
+  schedule:
+    - cron: "17 3 * * *"
+  workflow_dispatch:
+
+env:
+  CARGO_TERM_COLOR: always
+  ASAN_OPTIONS: quarantine_size_mb=1:malloc_context_size=0
+
+jobs:
+  fuzz_build:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: dtolnay/rust-toolchain@nightly
+      - name: Install cargo-fuzz
+        run: cargo install cargo-fuzz --locked
+      - name: Build fuzz targets
+        run: cargo +nightly fuzz build
+
+  fuzz_smoke:
+    if: github.event_name == 'pull_request' || github.event_name == 'workflow_dispatch'
+    runs-on: ubuntu-latest
+    needs: fuzz_build
+    steps:
+      - uses: actions/checkout@v4
+      - uses: dtolnay/rust-toolchain@nightly
+      - name: Install cargo-fuzz
+        run: cargo install cargo-fuzz --locked
+      - name: Smoke run router
+        run: cargo +nightly fuzz run fuzz_router_match -- -max_len=512 -max_total_time=45 -rss_limit_mb=512
+      - name: Smoke run query
+        run: cargo +nightly fuzz run fuzz_query_decode -- -max_len=1024 -max_total_time=45 -rss_limit_mb=512
+
+  fuzz_nightly:
+    if: github.event_name == 'schedule' || github.event_name == 'workflow_dispatch'
+    runs-on: ubuntu-latest
+    needs: fuzz_build
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+          - target: fuzz_router_match
+            max_len: 512
+          - target: fuzz_query_decode
+            max_len: 1024
+          - target: fuzz_extractor_typed
+            max_len: 4096
+          - target: fuzz_openapi_gen
+            max_len: 256
+    steps:
+      - uses: actions/checkout@v4
+      - uses: dtolnay/rust-toolchain@nightly
+      - name: Install cargo-fuzz
+        run: cargo install cargo-fuzz --locked
+      - name: Nightly fuzz run
+        run: cargo +nightly fuzz run ${{ matrix.target }} -- -max_len=${{ matrix.max_len }} -max_total_time=300 -rss_limit_mb=512