diff --git a/docs/labs/create_checker.md b/docs/labs/create_checker.md
index 7a490772..6d30b14c 100644
--- a/docs/labs/create_checker.md
+++ b/docs/labs/create_checker.md
@@ -442,8 +442,8 @@ hints: [
     absent: ", $",
     text: "This is a parameter, it must end with a comma.",
     examples: [
-      [ "  " ]
-    ]
+      [ "  " ],
+    ],
   },
   {
     present: "(isint|Isint|IsInt|ISINT)",
@@ -451,9 +451,9 @@ hints: [
     examples: [
       [ "  query('id').isint()," ],
       [ "  query('id').IsInt()," ],
-    ]
-  }
-]
+    ],
+  },
+],
 ~~~~
 
 The first hint triggers when the user attempt does *not* contain the
@@ -475,12 +475,17 @@ make smaller changes, test them, and once they work
 check them in. That way you won't need to debug a long complicated
 set of changes.
 
-Please create tests! You can create test cases for attempts
-(`successes` should pass, `failures` should fail), and test cases
-to ensure the hints work correctly.
+Please create tests! You should create test cases for full attempts
+(`successes` should pass, `failures` should fail) and test cases
+for hints (`examples`).
 Remember, hints are checked in order - it's possible to create a hint
 that won't trigger because something earlier would always match.
-These tests are automatically checked every time the page is (re)loaded.
+All tests are automatically re-run every time the page is (re)loaded.
+
+In a hint, `examples` is an array of examples that should trigger the hint.
+Each example is an array of answers. If you use an index, the other index
+values aren't considered. We suggest using `null` for array entries
+that aren't relevant for the test.
 
 ### Debugging
 
diff --git a/docs/labs/mass-test b/docs/labs/mass-test
index 39937a55..3a8e21a2 100755
--- a/docs/labs/mass-test
+++ b/docs/labs/mass-test
@@ -2,9 +2,11 @@
 
 # Mass open all lab files. Do this by opening every lab in a web browser,
 # which will invoke each lab's built-in tests.
+# Each file should have a yellow input field (so the JavaScript ran)
+# and *not* show a test failure (so all embedded tests passed).
 
 # Create a list of labs
-grep -o '[A-Za-z0-9_-]*\.html' README.md | sort |uniq > ,1
+grep -l 'src=.*checker.js' [a-z]*.html > ,1
 
 OPENER=xdg-open
 if ! which "$OPENER" >/dev/null; then