diff --git a/.travis.yml b/.travis.yml
index a392a526d0620eab656396d8f3a7522d3453232c..dc78028717733a6e398cbb8ad601fef40f58db75 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -28,4 +28,5 @@ after_success:
 
 env:
   global:
-    - secure: "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"
\ No newline at end of file
+    - secure: "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"
+    - RUST_TEST_THREADS=1
diff --git a/appveyor.yml b/appveyor.yml
index 070c05d64e5b5196cf4b6670b9d0f7da08fe82eb..ec22c1b4e6999701df7261af4a97a9e063eb30c5 100644
--- a/appveyor.yml
+++ b/appveyor.yml
@@ -8,5 +8,8 @@ install:
 
 build: false
 
+environment:
+  RUST_TEST_THREADS: 1
+
 test_script:
-  - cargo test --verbose
\ No newline at end of file
+  - cargo test --verbose
diff --git a/src/server.rs b/src/server.rs
index 9bdb9e42b5b821332a68fad1ae4b6cef0204b30f..54514a8dcefdf98c07c82594c6eb8ebaf9377b7a 100644
--- a/src/server.rs
+++ b/src/server.rs
@@ -177,7 +177,7 @@ mod test {
 	fn test_echo_server() {
 		let mut server = CoAPServer::new("127.0.0.1:5683").unwrap();
 		server.handle(request_handler).unwrap();
-		
+
 		let client = CoAPClient::new("127.0.0.1:5683").unwrap();
 		let mut packet = Packet::new();
 		packet.header.set_version(1);
@@ -191,4 +191,22 @@ mod test {
 		let recv_packet = client.receive().unwrap();
 		assert_eq!(recv_packet.payload, b"test-echo".to_vec());
 	}
-}
\ No newline at end of file
+
+	#[test]
+	fn test_echo_server_no_token() {
+		let mut server = CoAPServer::new("127.0.0.1:5683").unwrap();
+		server.handle(request_handler).unwrap();
+
+		let client = CoAPClient::new("127.0.0.1:5683").unwrap();
+		let mut packet = Packet::new();
+		packet.header.set_version(1);
+		packet.header.set_type(PacketType::Confirmable);
+		packet.header.set_code("0.01");
+		packet.header.set_message_id(1);
+		packet.add_option(OptionType::UriPath, b"test-echo".to_vec());
+		client.send(&packet).unwrap();
+
+		let recv_packet = client.receive().unwrap();
+		assert_eq!(recv_packet.payload, b"test-echo".to_vec());
+	}
+}