From f67ab295d088f8cb1a3407d1b8c187a7187c7e95 Mon Sep 17 00:00:00 2001
From: Peter Bex <peter@more-magic.net>
Date: Sun, 12 May 2019 10:34:10 +0200
Subject: Add LISTEN/NOTIFY support

This really is just a matter of reading out notifications when they're
available.  Also, we offer a way to explicitly wait for notifications.
---
 tests/run.scm | 78 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 76 insertions(+), 2 deletions(-)

(limited to 'tests/run.scm')

diff --git a/tests/run.scm b/tests/run.scm
index 0469929..80cf799 100644
--- a/tests/run.scm
+++ b/tests/run.scm
@@ -4,7 +4,8 @@
         test
         postgresql
         sql-null
-        srfi-4)
+        srfi-4
+        srfi-18)
 
 (define-syntax test-error*
   (syntax-rules ()
@@ -942,7 +943,80 @@
                      (query conn "SELECT * FROM chicken_pgsql_test")))
              isolation: 'serializable))
       (disconnect conn2)))
-  )
+)
+
+
+;; This testing code is pretty hairy
+(test-group "LISTEN/NOTIFY"
+  (let ((received-channel #f)
+        (received-pid #f)
+        (received-message #f)
+        (pid1 (value-at (query conn "SELECT pg_backend_pid()"))))
+
+    (define (reset-received-values!)
+      (set! received-channel #f)
+      (set! received-pid #f)
+      (set! received-message #f))
+
+    (query conn "LISTEN \"testing channel\"")
+    (query conn "LISTEN \"unused channel\"")
+
+    (set-notify-handler! conn (lambda (channel pid message)
+                                (set! received-channel channel)
+                                (set! received-pid pid)
+                                (set! received-message message)))
+
+    (query conn "NOTIFY \"testing channel\", 'this is a test'")
+
+    (test "Notification handler is immediately invoked for own connection"
+          `("testing channel" ,pid1 "this is a test")
+          (list received-channel pid1 received-message))
+
+    (reset-received-values!)
+
+    (let* ((conn2 (connect '((dbname . test))))
+           (pid2 (value-at (query conn2 "SELECT pg_backend_pid()"))))
+      (query conn2 "NOTIFY \"testing channel\", 'another test'")
+
+      (test "Notification handler for connection 1 is not invoked when notifying from connection 2"
+            `(#f #f #f)
+            (list received-channel received-pid received-message))
+
+      (query conn "SELECT 1")
+      (test "Notification handler is invoked after performing next query"
+            `("testing channel" ,pid2 "another test")
+            (list received-channel received-pid received-message))
+
+      (reset-received-values!)
+
+      ;; This sucks, we have to do this from another thread
+      (thread-start!
+       (lambda ()
+         (thread-sleep! 0.1)
+         (query conn2 "NOTIFY \"testing channel\", 'hi'")))
+
+      (test "Waiting manually for a short while does nothing yet"
+            `(#f #f #f)
+            (begin (wait-for-notifications! conn 1)
+                   (list received-channel received-pid received-message)))
+
+      (test "Waiting long enough returns the notification"
+            `("testing channel" ,pid2 "hi")
+            (begin (wait-for-notifications! conn 5000)
+                   (list received-channel received-pid received-message)))
+
+      (reset-received-values!)
+
+      ;; And once more
+      (thread-start!
+       (lambda ()
+         (thread-sleep! 0.01)
+         (query conn2 "NOTIFY \"testing channel\", 'also hi'")))
+
+      (test "Waiting without timeout returns the notification"
+            `("testing channel" ,pid2 "also hi")
+            (begin (wait-for-notifications! conn #f)
+                   (list received-channel received-pid received-message))))))
 
 (test-end)
 
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