diff --git a/test/browser/tests.js b/test/browser/tests.js
index ceb882b..b7d9c87 100644
--- a/test/browser/tests.js
+++ b/test/browser/tests.js
@@ -74,7 +74,10 @@ describe('isProbablyPrime', function () {
 // <--
 
 const bitLengths = [
+  8,
+  255,
   256,
+  258,
   512,
   1024,
   2048,
diff --git a/test/prime.js b/test/prime.js
index 1263c50..acbdde2 100644
--- a/test/prime.js
+++ b/test/prime.js
@@ -7,7 +7,10 @@ const chai = require('chai')
 // <--
 
 const bitLengths = [
+  8,
+  255,
   256,
+  258,
   512,
   1024,
   2048,