test: [#1069] example of capturing tracing output

Author: josecelano

tests/common/logging.rs

@@ -10,9 +10,11 @@
 //! ´´´
 //!
 
-use std::sync::Once;
+use std::io;
+use std::sync::{Arc, Mutex, Once};
 
 use tracing::level_filters::LevelFilter;
+use tracing_subscriber::fmt::MakeWriter;
 
 #[allow(dead_code)]
 pub static INIT: Once = Once::new();
@@ -28,3 +30,92 @@ pub fn tracing_stderr_init(filter: LevelFilter) {
 
     tracing::info!("Logging initialized");
 }
+
+#[allow(dead_code)]
+pub fn tracing_init_with_capturer(filter: LevelFilter, log_capturer: Arc<Mutex<LogCapturer>>) {
+    let writer = LogCapturerWrapper::new(log_capturer);
+
+    let builder = tracing_subscriber::fmt()
+        .with_max_level(filter)
+        .with_ansi(true)
+        .with_writer(writer);
+
+    builder.pretty().with_file(true).init();
+
+    tracing::info!("Logging initialized");
+}
+
+pub struct LogCapturerWrapper {
+    inner: Arc<Mutex<LogCapturer>>,
+}
+
+impl LogCapturerWrapper {
+    pub fn new(inner: Arc<Mutex<LogCapturer>>) -> Self {
+        Self { inner }
+    }
+}
+
+impl<'a> tracing_subscriber::fmt::MakeWriter<'a> for LogCapturerWrapper {
+    type Writer = LogCapturerGuard;
+
+    fn make_writer(&'a self) -> Self::Writer {
+        LogCapturerGuard {
+            inner: self.inner.clone(),
+        }
+    }
+}
+
+pub struct LogCapturerGuard {
+    inner: Arc<Mutex<LogCapturer>>,
+}
+
+impl io::Write for LogCapturerGuard {
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+        let mut capturer = self.inner.lock().unwrap();
+        capturer.write(buf)
+    }
+
+    fn flush(&mut self) -> io::Result<()> {
+        let mut capturer = self.inner.lock().unwrap();
+        capturer.flush()
+    }
+}
+
+#[derive(Debug, Default)]
+pub struct LogCapturer {
+    output: String,
+}
+
+impl LogCapturer {
+    pub fn new() -> Self {
+        Self::default()
+    }
+
+    pub fn contains(&self, message: &str) -> bool {
+        self.output.contains(message)
+    }
+}
+
+impl io::Write for LogCapturer {
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+        let out_str = String::from_utf8_lossy(buf);
+
+        print!("{out_str}");
+
+        self.output.push_str(&out_str);
+
+        Ok(buf.len())
+    }
+
+    fn flush(&mut self) -> io::Result<()> {
+        Ok(())
+    }
+}
+
+impl<'a> MakeWriter<'a> for LogCapturer {
+    type Writer = Self;
+
+    fn make_writer(&'a self) -> Self::Writer {
+        Self::default()
+    }
+}

tests/servers/api/v1/contract/context/auth_key.rs

@@ -1,11 +1,12 @@
+use std::sync::{Arc, Mutex};
 use std::time::Duration;
 
 use serde::Serialize;
 use torrust_tracker::core::auth::Key;
 use torrust_tracker_test_helpers::configuration;
 use tracing::level_filters::LevelFilter;
 
-use crate::common::logging::{tracing_stderr_init, INIT};
+use crate::common::logging::{tracing_init_with_capturer, tracing_stderr_init, LogCapturer, INIT};
 use crate::servers::api::connection_info::{connection_with_invalid_token, connection_with_no_token};
 use crate::servers::api::v1::asserts::{
     assert_auth_key_utf8, assert_failed_to_delete_key, assert_failed_to_generate_key, assert_failed_to_reload_keys,
@@ -250,8 +251,10 @@ async fn should_fail_deleting_an_auth_key_when_the_key_id_is_invalid() {
 
 #[tokio::test]
 async fn should_fail_when_the_auth_key_cannot_be_deleted() {
+    let log_capturer = Arc::new(Mutex::new(LogCapturer::new()));
+
     INIT.call_once(|| {
-        tracing_stderr_init(LevelFilter::ERROR);
+        tracing_init_with_capturer(LevelFilter::ERROR, log_capturer.clone());
     });
 
     let env = Started::new(&configuration::ephemeral().into()).await;
@@ -271,6 +274,10 @@ async fn should_fail_when_the_auth_key_cannot_be_deleted() {
 
     assert_failed_to_delete_key(response).await;
 
+    // We expect to see a 500 error, it's the current API behavior
+    assert!(log_capturer.lock().unwrap().contains("ERROR tower_http"));
+    assert!(log_capturer.lock().unwrap().contains("500 Internal Server Error"));
+
     env.stop().await;
 }