diff --git a/Cargo.lock b/Cargo.lock
index c9496fc..f7c7817 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -76,7 +76,7 @@ dependencies = [
 
 [[package]]
 name = "fourth"
-version = "0.1.0"
+version = "0.1.1"
 dependencies = [
  "futures",
  "log",
diff --git a/Cargo.toml b/Cargo.toml
index 7203959..494433c 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,7 +1,7 @@
 [package]
 name = "fourth"
-version = "0.1.0"
-edition = "2018"
+version = "0.1.1"
+edition = "2021"
 authors = ["LI Rui <lr_cn@outlook.com>"]
 license = "Apache-2.0"
 description = "Simple and fast layer 4 proxy in Rust"
diff --git a/src/config.rs b/src/config.rs
index 67d3cad..01f766c 100644
--- a/src/config.rs
+++ b/src/config.rs
@@ -54,9 +54,11 @@ fn load_config(path: &str) -> Result<BaseConfig, ConfigError> {
     }
 
     let log_level = parsed.log.clone().unwrap_or_else(|| "info".to_string());
-    std::env::set_var("FOURTH_LOG", log_level.clone());
-    pretty_env_logger::init_custom_env("FOURTH_LOG");
-    debug!("Set log level to {}", log_level);
+    if !log_level.eq("disable") {
+        std::env::set_var("FOURTH_LOG", log_level.clone());
+        pretty_env_logger::init_custom_env("FOURTH_LOG");
+        debug!("Set log level to {}", log_level);
+    }
 
     debug!("Config version {}", parsed.version);
 
@@ -74,3 +76,17 @@ impl From<serde_yaml::Error> for ConfigError {
         ConfigError::Yaml(err)
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_load_config() {
+        let config = Config::new("tests/config.yaml").unwrap();
+        assert_eq!(config.base.version, 1);
+        assert_eq!(config.base.log.unwrap(), "disable");
+        assert_eq!(config.base.servers.len(), 2);
+        assert_eq!(config.base.upstream.len(), 2);
+    }
+}
diff --git a/src/servers/mod.rs b/src/servers/mod.rs
index c042a4c..3f83ec4 100644
--- a/src/servers/mod.rs
+++ b/src/servers/mod.rs
@@ -206,3 +206,30 @@ where
         Err(_) => Ok(0),
     }
 }
+
+#[cfg(test)]
+mod test {
+    use std::thread::{self, sleep};
+    use std::time::Duration;
+
+    use super::*;
+
+    #[tokio::test]
+    async fn test_echo_server() {
+        use crate::config::Config;
+        let config = Config::new("tests/config.yaml").unwrap();
+        let mut server = Server::new(config.base);
+        thread::spawn(move || {
+            let _ = server.run();
+        });
+        sleep(Duration::from_secs(1)); // wait for server to start
+        let mut conn = TcpStream::connect("127.0.0.1:54956").await.unwrap();
+        let mut buf = [0u8; 1];
+        for i in 0..=255u8 {
+            conn.write(&[i]).await.unwrap();
+            conn.read(&mut buf).await.unwrap();
+            assert_eq!(&buf, &[i]);
+        }
+        conn.shutdown().await.unwrap();
+    }
+}
diff --git a/src/servers/tls.rs b/src/servers/tls.rs
index 9bf87a4..398c36a 100644
--- a/src/servers/tls.rs
+++ b/src/servers/tls.rs
@@ -51,3 +51,53 @@ pub fn get_sni(buf: &[u8]) -> Vec<String> {
 
     snis
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_sni_extract() {
+        const BUF: [u8; 517] = [
+            0x16, 0x03, 0x01, 0x02, 0x00, 0x01, 0x00, 0x01, 0xfc, 0x03, 0x03, 0x35, 0x7a, 0xba,
+            0x3d, 0x89, 0xd2, 0x5e, 0x7a, 0xa2, 0xd4, 0xe5, 0x6d, 0xd5, 0xa3, 0x98, 0x41, 0xb0,
+            0xae, 0x41, 0xfc, 0xe6, 0x64, 0xfd, 0xae, 0x0b, 0x27, 0x6d, 0x90, 0xa8, 0x0a, 0xfa,
+            0x90, 0x20, 0x59, 0x6f, 0x13, 0x18, 0x4a, 0xd1, 0x1c, 0xc4, 0x83, 0x8c, 0xfc, 0x93,
+            0xac, 0x6b, 0x3b, 0xac, 0x67, 0xd0, 0x36, 0xb0, 0xa2, 0x1b, 0x04, 0xf7, 0xde, 0x02,
+            0xfb, 0x96, 0x1e, 0xdc, 0x76, 0xa8, 0x00, 0x20, 0x2a, 0x2a, 0x13, 0x01, 0x13, 0x02,
+            0x13, 0x03, 0xc0, 0x2b, 0xc0, 0x2f, 0xc0, 0x2c, 0xc0, 0x30, 0xcc, 0xa9, 0xcc, 0xa8,
+            0xc0, 0x13, 0xc0, 0x14, 0x00, 0x9c, 0x00, 0x9d, 0x00, 0x2f, 0x00, 0x35, 0x01, 0x00,
+            0x01, 0x93, 0xea, 0xea, 0x00, 0x00, 0x00, 0x00, 0x00, 0x13, 0x00, 0x11, 0x00, 0x00,
+            0x0e, 0x77, 0x77, 0x77, 0x2e, 0x6c, 0x69, 0x72, 0x75, 0x69, 0x2e, 0x74, 0x65, 0x63,
+            0x68, 0x00, 0x17, 0x00, 0x00, 0xff, 0x01, 0x00, 0x01, 0x00, 0x00, 0x0a, 0x00, 0x0a,
+            0x00, 0x08, 0xba, 0xba, 0x00, 0x1d, 0x00, 0x17, 0x00, 0x18, 0x00, 0x0b, 0x00, 0x02,
+            0x01, 0x00, 0x00, 0x23, 0x00, 0x00, 0x00, 0x10, 0x00, 0x0e, 0x00, 0x0c, 0x02, 0x68,
+            0x32, 0x08, 0x68, 0x74, 0x74, 0x70, 0x2f, 0x31, 0x2e, 0x31, 0x00, 0x05, 0x00, 0x05,
+            0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x0d, 0x00, 0x12, 0x00, 0x10, 0x04, 0x03, 0x08,
+            0x04, 0x04, 0x01, 0x05, 0x03, 0x08, 0x05, 0x05, 0x01, 0x08, 0x06, 0x06, 0x01, 0x00,
+            0x12, 0x00, 0x00, 0x00, 0x33, 0x00, 0x2b, 0x00, 0x29, 0xba, 0xba, 0x00, 0x01, 0x00,
+            0x00, 0x1d, 0x00, 0x20, 0x3b, 0x45, 0xf9, 0xbc, 0x6e, 0x23, 0x86, 0x41, 0xa5, 0xb2,
+            0xf5, 0x03, 0xec, 0x67, 0x4a, 0xd7, 0x9a, 0x17, 0x9f, 0x0c, 0x38, 0x6d, 0x36, 0xf3,
+            0x4e, 0x5d, 0xa4, 0x7d, 0x15, 0x79, 0xa4, 0x3f, 0x00, 0x2d, 0x00, 0x02, 0x01, 0x01,
+            0x00, 0x2b, 0x00, 0x0b, 0x0a, 0xba, 0xba, 0x03, 0x04, 0x03, 0x03, 0x03, 0x02, 0x03,
+            0x01, 0x00, 0x1b, 0x00, 0x03, 0x02, 0x00, 0x02, 0x44, 0x69, 0x00, 0x05, 0x00, 0x03,
+            0x02, 0x68, 0x32, 0xda, 0xda, 0x00, 0x01, 0x00, 0x00, 0x15, 0x00, 0xc5, 0x00, 0x00,
+            0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+            0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+            0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+            0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+            0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+            0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+            0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+            0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+            0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+            0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+            0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+            0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+            0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+            0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+        ];
+        let sni = get_sni(&BUF);
+        assert!(sni[0] == "www.lirui.tech".to_string());
+    }
+}
diff --git a/tests/config.yaml b/tests/config.yaml
new file mode 100644
index 0000000..08709a6
--- /dev/null
+++ b/tests/config.yaml
@@ -0,0 +1,21 @@
+version: 1
+log: disable
+
+servers:
+  test_server:
+    listen:
+      - "0.0.0.0:21341"
+      - "[::]:21341"
+    tls: true
+    sni:
+      proxy.test.com: proxy
+      www.test.com: web
+    default: ban
+  echo_server:
+    listen:
+      - "0.0.0.0:54956"
+    default: echo
+
+upstream:
+  web: "127.0.0.1:8080"
+  proxy: "www.example.com:1024"
\ No newline at end of file