Add test example to README.md

README.md

@@ -224,6 +224,53 @@ Adds `shutdown_on_signal` and `shutdown_on_ctrl_c` to the scheduler.
 Both shuts the system down (stops the scheduler, removes all the tasks) when a signal
 was received.
 
+## Writing tests
+
+When doing a tokio::test, remember to have it run in a multi-threaded context otherwise the test
+will hang on `scheduler.add()`.
+
+For example:
+
+```rust
+
+#[cfg(test)]
+mod test {
+    use tokio_cron_scheduler::{Job, JobScheduler};
+    use tracing::{info, Level};
+    use tracing_subscriber::FmtSubscriber;
+
+    // Needs multi_thread to test, otherwise it hangs on scheduler.add()
+    #[tokio::test(flavor = "multi_thread", worker_threads = 2)]
+    // #[tokio::test]
+    async fn test_schedule() {
+        let subscriber = FmtSubscriber::builder()
+            .with_max_level(Level::TRACE)
+            .finish();
+        tracing::subscriber::set_global_default(subscriber)
+            .expect("Setting default subscriber failed");
+
+        info!("Create scheduler");
+        let scheduler = JobScheduler::new().await.unwrap();
+        info!("Add job");
+        scheduler
+            .add(
+                Job::new_async("*/1  * * * * *", |_, _| {
+                    Box::pin(async {
+                        info!("Run every seconds");
+                    })
+                })
+                .unwrap(),
+            )
+            .await
+            .expect("Should be able to add a job");
+
+        scheduler.start().await.unwrap();
+
+        tokio::time::sleep(core::time::Duration::from_secs(20)).await;
+    }
+}
+```
+
 ## Examples
 
 ### simple