feat: add SSE connection state and reconnection logic

test/noise-sse-test.el

@@ -29,5 +29,31 @@
   (let ((event "\n\n"))
     (should (null (noise-sse--parse-event event)))))
 
+(ert-deftest noise-sse--initial-state ()
+  "SSE client starts in disconnected state."
+  (let ((noise-sse--process nil)
+        (noise-sse--reconnect-timer nil)
+        (noise-sse--reconnect-delay 1))
+    (should (null noise-sse--process))
+    (should (null noise-sse--reconnect-timer))
+    (should (= 1 noise-sse--reconnect-delay))))
+
+(ert-deftest noise-sse--reconnect-delay-backoff ()
+  "Reconnect delay doubles on each attempt."
+  (let ((noise-sse--reconnect-delay 1))
+    (noise-sse--increase-reconnect-delay)
+    (should (= 2 noise-sse--reconnect-delay))
+    (noise-sse--increase-reconnect-delay)
+    (should (= 4 noise-sse--reconnect-delay))
+    (noise-sse--increase-reconnect-delay)
+    (should (= 8 noise-sse--reconnect-delay))))
+
+(ert-deftest noise-sse--reconnect-delay-max ()
+  "Reconnect delay caps at max value."
+  (let ((noise-sse--reconnect-delay 32)
+        (noise-sse-max-reconnect-delay 60))
+    (noise-sse--increase-reconnect-delay)
+    (should (= 60 noise-sse--reconnect-delay))))
+
 (provide 'noise-sse-test)
 ;;; noise-sse-test.el ends here