diff --git a/docsite/site/content/stdlib/testing.md b/docsite/site/content/stdlib/testing.md
index 2b14445..ef60d88 100644
--- a/docsite/site/content/stdlib/testing.md
+++ b/docsite/site/content/stdlib/testing.md
@@ -55,12 +55,13 @@ assert t.ok{
 
 ### equal assertion
 
-The `equal` assertion module tests that two items are equal. It has two parameters.
+The `equal` assertion module tests that two items are equal. It has three
+parameters.
 
 * `left` which is required and is the left hand side expression to compare
 * `right` which is required is the right hand side expression to compare.
-
-This module will create a description for you from the compared values.
+* `desc` which is an optional description to output for your test. This defaults to
+  a description created from the compared values.
 
 ```
 let t = import "std/testing.ucg".asserts{};
@@ -78,8 +79,8 @@ parameters.
 
 * `left` which is required and is the left hand side expression to compare
 * `right` which is required is the right hand side expression to compare.
-
-This module will create a description for you from the compared values.
+* `desc` which is an optional description to output for your test. This defaults to
+  a description created from the compared values.
 
 ```
 let t = import "std/testing.ucg".asserts{};
diff --git a/std/testing.ucg b/std/testing.ucg
index 122b553..3c69b79 100644
--- a/std/testing.ucg
+++ b/std/testing.ucg
@@ -42,10 +42,13 @@ let asserts = module{
         left=NULL,
         // right value for deep equal comparison.
         right=NULL,
+        desc=NULL,
     } => {
         let ok = mod.left == mod.right;
 
-        let desc =  "@ == @" % (mod.left, mod.right);
+        let desc = select (mod.desc == NULL), "@ == @" % (mod.left, mod.right), {
+            false = mod.desc,
+        };
     };
 
     // Asserts that two values are not equal. Does deep equal comparisons.
@@ -54,9 +57,12 @@ let asserts = module{
         left=NULL,
         // right value for deep equal comparison.
         right=NULL,
+        desc=NULL,
     } => {
         let ok = mod.left != mod.right;
 
-        let desc = "@ != @" % (mod.left, mod.right);
+        let desc = select (mod.desc == NULL), "@ != @" % (mod.left, mod.right), {
+            false = mod.desc,
+        };
     };
 };
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