CI: Run benchmarks

We just added benchmarks to the crate, run them in CI when testing with
the nightly toolchain.

Author: tcharding

.github/workflows/rust.yml

@@ -45,6 +45,7 @@ jobs:
       - name: Running test script
         env:
           DO_FMT: true
+          DO_BENCH: true
         run: ./contrib/test.sh
 
   MSRV:

contrib/test.sh

@@ -67,4 +67,16 @@ if [ "$MIN_VERSION" != true ]; then
     check "std arrayvec"
 fi
 
+# Bench if told to.
+if [ "$DO_BENCH" = true ]
+then
+    # Technically we could use beta too but we only run this in CI using nightly.
+    if [ "$NIGHTLY" = false ]; then
+        echo "DO_BENCH requires a nightly toolchain (consider using RUSTUP_TOOLCHAIN=nightly)"
+        exit 1
+    fi
+
+    RUSTFLAGS='--cfg=bench' cargo bench
+fi
+
 exit 0