diff --git a/test/base64.js b/test/base64.js
index 5e25a7e..ca724a6 100644
--- a/test/base64.js
+++ b/test/base64.js
@@ -12,6 +12,10 @@ var atob = base64.atob;
 describe ('Base64.js', function() {
 
   it ('can encode ASCII input', function() {
+    for (let i = 0; i < 255; i++) {
+      const char = String.fromCharCode(i);
+      assert.strictEqual (btoa (char), btoa(char));
+    }
     assert.strictEqual (btoa (''), '');
     assert.strictEqual (btoa ('f'), 'Zg==');
     assert.strictEqual (btoa ('fo'), 'Zm8=');
@@ -49,6 +53,10 @@ describe ('Base64.js', function() {
   });
 
   it ('can decode Base64-encoded input', function() {
+    for (let i = 0; i < 255; i++) {
+      const char = String.fromCharCode(i);
+      assert.strictEqual (atob(btoa (char)), char);
+    }
     assert.strictEqual (atob (''), '');
     assert.strictEqual (atob ('Zg=='), 'f');
     assert.strictEqual (atob ('Zm8='), 'fo');