diff --git a/knots/parallelism.scm b/knots/parallelism.scm
index a3b04c7..c98ca3f 100644
--- a/knots/parallelism.scm
+++ b/knots/parallelism.scm
@@ -217,9 +217,9 @@
       (if (null? active-channels)
           (map
            (match-lambda
-             ((#f . ('exception  exn))
+             ((#f . ('exception exn))
               (raise-exception exn))
-             ((#f . ('result  val))
+             ((#f . ('result val))
               val))
            channels-to-results)
           (loop
diff --git a/knots/resource-pool.scm b/knots/resource-pool.scm
index e55bdac..7da76b0 100644
--- a/knots/resource-pool.scm
+++ b/knots/resource-pool.scm
@@ -74,7 +74,7 @@
   (record-constructor &resource-pool-abort-add-resource))
 
 (define resource-pool-abort-add-resource-error?
-  (record-predicate &resource-pool-abort-add-resource))
+  (exception-predicate &resource-pool-abort-add-resource))
 
 (define-record-type <resource-pool>
   (make-resource-pool-record name channel destroy-condition configuration)
@@ -1196,7 +1196,7 @@
   (record-constructor &resource-pool-timeout))
 
 (define resource-pool-timeout-error?
-  (record-predicate &resource-pool-timeout))
+  (exception-predicate &resource-pool-timeout))
 
 (define &resource-pool-too-many-waiters
   (make-exception-type '&recource-pool-too-many-waiters
@@ -1217,7 +1217,7 @@
   (record-constructor &resource-pool-too-many-waiters))
 
 (define resource-pool-too-many-waiters-error?
-  (record-predicate &resource-pool-too-many-waiters))
+  (exception-predicate &resource-pool-too-many-waiters))
 
 (define &resource-pool-destroyed
   (make-exception-type '&recource-pool-destroyed
@@ -1233,7 +1233,7 @@
   (record-constructor &resource-pool-destroyed))
 
 (define resource-pool-destroyed-error?
-  (record-predicate &resource-pool-destroyed))
+  (exception-predicate &resource-pool-destroyed))
 
 (define &resource-pool-destroy-resource
   (make-exception-type '&recource-pool-destroy-resource
@@ -1244,7 +1244,7 @@
   (record-constructor &resource-pool-destroy-resource))
 
 (define resource-pool-destroy-resource-exception?
-  (record-predicate &resource-pool-destroy-resource))
+  (exception-predicate &resource-pool-destroy-resource))
 
 (define resource-pool-default-timeout-handler
   (make-parameter #f))
diff --git a/knots/thread-pool.scm b/knots/thread-pool.scm
index b176162..70d7292 100644
--- a/knots/thread-pool.scm
+++ b/knots/thread-pool.scm
@@ -198,7 +198,7 @@ from there, or #f if that would be an empty string."
    (record-accessor &thread-pool-timeout-error 'pool)))
 
 (define thread-pool-timeout-error?
-  (record-predicate &thread-pool-timeout-error))
+  (exception-predicate &thread-pool-timeout-error))
 
 (define* (make-fixed-size-thread-pool size
                                       #:key
diff --git a/knots/timeout.scm b/knots/timeout.scm
index 58306e0..a65a095 100644
--- a/knots/timeout.scm
+++ b/knots/timeout.scm
@@ -85,7 +85,7 @@
   (record-constructor &port-timeout-error))
 
 (define port-timeout-error?
-  (record-predicate &port-timeout-error))
+  (exception-predicate &port-timeout-error))
 
 (define &port-read-timeout-error
   (make-exception-type '&port-read-timeout-error
@@ -96,7 +96,7 @@
   (record-constructor &port-read-timeout-error))
 
 (define port-read-timeout-error?
-  (record-predicate &port-read-timeout-error))
+  (exception-predicate &port-read-timeout-error))
 
 (define &port-write-timeout-error
   (make-exception-type '&port-write-timeout-error
@@ -107,7 +107,7 @@
   (record-constructor &port-write-timeout-error))
 
 (define port-write-timeout-error?
-  (record-predicate &port-write-timeout-error))
+  (exception-predicate &port-write-timeout-error))
 
 (define (readable? port)
   "Test if PORT is writable."
diff --git a/knots/web-server.scm b/knots/web-server.scm
index 453db44..a0a3641 100644
--- a/knots/web-server.scm
+++ b/knots/web-server.scm
@@ -130,7 +130,7 @@ closes PORT, unless KEEP-ALIVE? is true."
   (record-constructor &request-body-ended-prematurely))
 
 (define request-body-ended-prematurely-error?
-  (record-predicate &request-body-ended-prematurely))
+  (exception-predicate &request-body-ended-prematurely))
 
 (define (request-body-port/knots r)
   (cond
diff --git a/tests.scm b/tests.scm
index a58eff0..0cca3b4 100644
--- a/tests.scm
+++ b/tests.scm
@@ -1,6 +1,7 @@
 (define-module (tests)
   #:use-module (ice-9 exceptions)
   #:use-module (fibers)
+  #:use-module (knots)
   #:export (run-fibers-for-tests
             assert-no-heap-growth))
 
@@ -15,9 +16,10 @@
                 (simple-format #t "running ~A\n" thunk)
                 (with-exception-handler
                     (lambda (exn)
-                      (backtrace)
+                      (print-backtrace-and-exception/knots exn)
                       (raise-exception exn))
-                  thunk)
+                  (lambda ()
+                    (start-stack #t (thunk))))
                 #t)
               #:unwind? #t))
           #:hz 0