diff --git a/t/mirror-img.lisp b/t/mirror-img.lisp
index 3bf008f..f4cb658 100644
--- a/t/mirror-img.lisp
+++ b/t/mirror-img.lisp
@@ -94,3 +94,23 @@
    "/images%21/dad%20alive.jpg"
    (mirror-img::url-encode-path "/images!/dad alive.jpg")))
 
+(define-test uri-explicit-port.http80 (:tags '(util))
+  (assert-eq
+   nil
+   (mirror-img::uri-explicit-port (quri:uri "http://xwx.moe/bird.png"))))
+
+(define-test uri-explicit-port.http443 (:tags '(util))
+  (assert-eq
+   443
+   (mirror-img::uri-explicit-port (quri:uri "http://xwx.moe:443/bird.png"))))
+
+(define-test uri-explicit-port.https27 (:tags '(util))
+  (assert-eq
+   27
+   (mirror-img::uri-explicit-port (quri:uri "http://xwx.moe:27/bird.png"))))
+
+(define-test uri-explicit-port.https443 (:tags '(util))
+  (assert-eq
+   nil
+   (mirror-img::uri-explicit-port (quri:uri "https://xwx.moe:443/bird.png"))))
+