Add benchmarks

Signed-off-by: George Robinson <george.robinson@grafana.com>

matchers/parse/bench_test.go

@@ -0,0 +1,39 @@
+// Copyright 2023 The Prometheus Authors
+// 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.
+
+package parse
+
+import (
+	"testing"
+)
+
+const (
+	simpleExample  = "{foo=\"bar\"}"
+	complexExample = "{foo=\"bar\",bar=~\"[a-zA-Z0-9+]\"}"
+)
+
+func BenchmarkParseSimple(b *testing.B) {
+	for i := 0; i < b.N; i++ {
+		if _, err := Parse(simpleExample); err != nil {
+			b.Fatal(err)
+		}
+	}
+}
+
+func BenchmarkParseComplex(b *testing.B) {
+	for i := 0; i < b.N; i++ {
+		if _, err := Parse(complexExample); err != nil {
+			b.Fatal(err)
+		}
+	}
+}