test case with code copied from grpc-java test

LICENSE

@@ -227,6 +227,7 @@ Pekko gRPC contains code from grpc-java <https://github.com/grpc/grpc-java>
 distributed under the Apache 2.0 license.
 
 - runtime/src/main/scala/org/apache/pekko/grpc/scaladsl/headers/PercentEncoding.scala
+- runtime/src/test/scala/org/apache/pekko/grpc/scaladsl/headers/HeadersSpec.scala
 - interop-tests/src/main/java/io/grpc/testing/integration2/TestServiceClient.java
 - interop-tests/src/main/java/io/grpc/testing/integration2/TestServiceServer.java
 - benchmark-java/src/main/java/org/apache/pekko/grpc/benchmarks/SocketAddressValidator.java

legal/RuntimeLicense.txt

@@ -206,5 +206,6 @@ Pekko gRPC contains code from grpc-java <https://github.com/grpc/grpc-java>
 distributed under the Apache 2.0 license.
 
 - runtime/src/main/scala/org/apache/pekko/grpc/scaladsl/headers/PercentEncoding.scala
+- runtime/src/test/scala/org/apache/pekko/grpc/scaladsl/headers/HeadersSpec.scala
 
 Copyright 2014 The gRPC Authors

runtime/src/test/scala/org/apache/pekko/grpc/scaladsl/headers/HeadersSpec.scala

@@ -1,10 +1,17 @@
 /*
- * Licensed to the Apache Software Foundation (ASF) under one or more
- * license agreements; and to You under the Apache License, version 2.0:
+ * Copyright 2014 The gRPC Authors
  *
- *   https://www.apache.org/licenses/LICENSE-2.0
+ * 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
  *
- * This file is part of the Apache Pekko project, which was derived from Akka.
+ *     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.
  */
 
 /*