added unit tests (closes #268 via b6f9a75 )

Author: jvmlet

grpc-spring-boot-starter-demo/src/test/java/org/lognet/springboot/grpc/recovery/ExceptionUtils.kt

@@ -4,4 +4,7 @@ import io.grpc.Status
 
 fun throwException(status: Status) {
     throw status.asException()
+}
+fun throwException(ex: Exception) {
+    throw ex
 }

grpc-spring-boot-starter-demo/src/test/java/org/lognet/springboot/grpc/recovery/GRpcStatusRuntimeExceptionTest.java

@@ -49,6 +49,9 @@ static class CustomService extends CustomServiceGrpc.CustomServiceImplBase {
 
             @Override
             public void anotherCustom(Custom.CustomRequest request, StreamObserver<Custom.CustomReply> responseObserver) {
+                if("NPE".equals(request.getName())){
+                    ExceptionUtilsKt.throwException(new NullPointerException());
+                }
                 ExceptionUtilsKt.throwException(Status.FAILED_PRECONDITION);
             }
 
@@ -62,6 +65,10 @@ public void custom(Custom.CustomRequest request, StreamObserver<Custom.CustomRep
             public StreamObserver<Custom.CustomRequest> customStream(StreamObserver<Custom.CustomReply> responseObserver) {
                 throw new StatusRuntimeException(Status.FAILED_PRECONDITION);
             }
+            @GRpcExceptionHandler
+            public Status  handle(NullPointerException e, GRpcExceptionScope scope ){
+                return Status.DATA_LOSS;
+            }
 
         }
 
@@ -114,4 +121,12 @@ public void statusExceptionTest() {
         assertThat(statusRuntimeException.getStatus(), is(Status.FAILED_PRECONDITION));
     }
 
+    @Test
+    public void npeExceptionTest() {
+        final StatusRuntimeException statusRuntimeException = assertThrows(StatusRuntimeException.class, () ->
+                CustomServiceGrpc.newBlockingStub(getChannel()).anotherCustom(Custom.CustomRequest.newBuilder().setName("NPE").build())
+        );
+        assertThat(statusRuntimeException.getStatus(), is(Status.DATA_LOSS));
+    }
+
 }