feat(kanban): acknowledge idempotent server command

req: sync/001\nreq: sync/005\nreq: sync/006\nreq: sync/007\nreq: sync/008\nreq: sync/012\nreq: sync/013

examples/kanban/tests/browser_e2e.rs

@@ -88,6 +88,131 @@ async fn server_first_route_does_not_load_optional_client_assets() -> WebDriverR
     result.and(quit)
 }
 
+#[tokio::test]
+async fn idempotent_server_command_is_acknowledged_after_reconnect() -> WebDriverResult<()> {
+    // test req: sync/001 req: sync/005 req: sync/006 req: sync/007
+    // test req: sync/008 req: sync/012 req: sync/013
+    let app_port = available_port();
+    let app_addr = format!("127.0.0.1:{app_port}");
+    let mut app = Command::new(env!("CARGO_BIN_EXE_hemx-kanban-example"));
+    app.env("HEMX_KANBAN_ADDR", &app_addr);
+    let _app = TestProcess::start(app, "hemx-kanban", &app_addr, STARTUP_TIMEOUT)
+        .expect("start ready hemx-kanban");
+
+    let webdriver_port = available_port();
+    let webdriver_addr = format!("127.0.0.1:{webdriver_port}");
+    let mut webdriver = Command::new("geckodriver");
+    webdriver.arg("--port").arg(webdriver_port.to_string());
+    let _webdriver = TestProcess::start(webdriver, "geckodriver", &webdriver_addr, STARTUP_TIMEOUT)
+        .expect("start ready geckodriver");
+
+    let mut caps = DesiredCapabilities::firefox();
+    caps.set_headless()?;
+    let driver = WebDriver::new(&format!("http://{webdriver_addr}"), caps).await?;
+    let result = async {
+        driver.goto(&format!("http://{app_addr}/")).await?;
+        driver.find(By::Css("section[data-hemx-root='kanban']")).await?;
+        driver
+            .execute(
+                r#"
+                window.__syncProof = { ready: false, opens: 0, events: [], error: null };
+                (async () => {
+                  const endpoint = '/sync/commands?command_id=actor-1%3A1&card_id=1';
+                  const firstResponse = await fetch(endpoint, { method: 'POST' });
+                  const first = await firstResponse.json();
+                  const duplicateResponse = await fetch(endpoint, { method: 'POST' });
+                  const duplicate = await duplicateResponse.json();
+                  const conflictResponse = await fetch('/sync/commands?command_id=actor-1%3A1&card_id=2', { method: 'POST' });
+                  const conflict = await conflictResponse.json();
+                  window.__syncProof.command = {
+                    firstStatus: firstResponse.status,
+                    duplicateStatus: duplicateResponse.status,
+                    first,
+                    duplicate,
+                    conflictStatus: conflictResponse.status,
+                    conflict,
+                  };
+                  const source = new EventSource('/sync/acknowledgements?after=0&reconnect=browser-proof');
+                  source.onopen = () => { window.__syncProof.opens += 1; };
+                  source.addEventListener('acknowledgement', (event) => {
+                    window.__syncProof.events.push({ id: event.lastEventId, acknowledgement: JSON.parse(event.data) });
+                    window.__syncProof.ready = true;
+                    source.close();
+                  });
+                  source.onerror = () => {
+                    if (source.readyState === EventSource.CLOSED && !window.__syncProof.ready) {
+                      window.__syncProof.error = 'acknowledgement stream closed';
+                    }
+                  };
+                })().catch((error) => { window.__syncProof.error = String(error); });
+                return true;
+                "#,
+                Vec::new(),
+            )
+            .await?;
+        wait_until(
+            &driver,
+            "return window.__syncProof.ready === true || window.__syncProof.error !== null",
+        )
+        .await?;
+        let proof = driver
+            .execute("return window.__syncProof", Vec::new())
+            .await?
+            .json()
+            .clone();
+        assert!(proof["error"].is_null(), "sync failed: {proof}");
+        assert!(
+            proof["opens"].as_u64().is_some_and(|opens| opens >= 2),
+            "transport did not reconnect: {proof}"
+        );
+        assert_eq!(proof["command"]["firstStatus"], 200);
+        assert_eq!(proof["command"]["duplicateStatus"], 200);
+        assert_eq!(proof["command"]["first"], proof["command"]["duplicate"]);
+        assert_eq!(proof["command"]["first"]["commandId"], "actor-1:1");
+        assert_eq!(proof["command"]["first"]["serverSequence"], 1);
+        assert_eq!(proof["command"]["first"]["cardId"], 1);
+        assert_eq!(proof["command"]["first"]["canonicalColumn"], "done");
+        assert_eq!(proof["command"]["first"]["status"], "accepted");
+        assert_eq!(proof["command"]["conflictStatus"], 409);
+        assert_eq!(
+            proof["command"]["conflict"]["error"],
+            "command_id was already used for a different payload"
+        );
+        assert_eq!(proof["events"].as_array().map(Vec::len), Some(1));
+        assert_eq!(proof["events"][0]["id"], "1");
+        assert_eq!(
+            proof["events"][0]["acknowledgement"],
+            proof["command"]["first"]
+        );
+
+        driver.refresh().await?;
+        let canonical = driver
+            .execute(
+                "return [...document.querySelectorAll('section.column')].map((column) => ({ title: column.querySelector('h2').textContent, cards: [...column.querySelectorAll('[data-key]')].map((card) => card.dataset.key) }))",
+                Vec::new(),
+            )
+            .await?
+            .json()
+            .clone();
+        assert_eq!(canonical[2]["title"], "Done");
+        assert_eq!(canonical[2]["cards"], serde_json::json!(["1", "3"]));
+        Ok(())
+    }
+    .await;
+    let quit = driver.quit().await;
+    result.and(quit)
+}
+
+async fn wait_until(driver: &WebDriver, script: &str) -> WebDriverResult<()> {
+    for _ in 0..200 {
+        if driver.execute(script, Vec::new()).await?.json().as_bool() == Some(true) {
+            return Ok(());
+        }
+        tokio::time::sleep(Duration::from_millis(25)).await;
+    }
+    panic!("browser condition timed out: {script}");
+}
+
 fn available_port() -> u16 {
     TcpListener::bind("127.0.0.1:0")
         .expect("reserve browser test port")