diff --git a/test/fixtures/expected/extend-equal-single.jpg b/test/fixtures/expected/extend-equal-single.jpg
new file mode 100644
index 00000000..f7da5177
Binary files /dev/null and b/test/fixtures/expected/extend-equal-single.jpg differ
diff --git a/test/unit/extend.js b/test/unit/extend.js
index c17758a4..fae8be87 100644
--- a/test/unit/extend.js
+++ b/test/unit/extend.js
@@ -6,6 +6,18 @@ const sharp = require('../../');
 const fixtures = require('../fixtures');
 
 describe('Extend', function () {
+  it('extend all sides equally via a single value', function (done) {
+    sharp(fixtures.inputJpg)
+      .resize(120)
+      .extend(10)
+      .toBuffer(function (err, data, info) {
+        if (err) throw err;
+        assert.strictEqual(140, info.width);
+        assert.strictEqual(118, info.height);
+        fixtures.assertSimilar(fixtures.expected('extend-equal-single.jpg'), data, done);
+      });
+  });
+
   it('extend all sides equally with RGB', function (done) {
     sharp(fixtures.inputJpg)
       .resize(120)