diff --git a/implementations/javascript/packages/core/test/bytes.test.ts b/implementations/javascript/packages/core/test/bytes.test.ts
index 9948324..1330b73 100644
--- a/implementations/javascript/packages/core/test/bytes.test.ts
+++ b/implementations/javascript/packages/core/test/bytes.test.ts
@@ -82,37 +82,39 @@ describe('immutable byte arrays', () => {
 });
 
 describe('base64 decoder', () => {
-    describe('RFC4648 tests', () => {
-        it('10.0', () => expect(decodeBase64("")).is(Bytes.of()));
-        it('10.1', () => expect(decodeBase64("Zg==")).is(Bytes.of(102)));
-        it('10.2', () => expect(decodeBase64("Zm8=")).is(Bytes.of(102, 111)));
-        it('10.3', () => expect(decodeBase64("Zm9v")).is(Bytes.of(102, 111, 111)));
-        it('10.4', () => expect(decodeBase64("Zm9vYg==")).is(Bytes.of(102, 111, 111, 98)));
-        it('10.5', () => expect(decodeBase64("Zm9vYmE=")).is(Bytes.of(102, 111, 111, 98, 97)));
-        it('10.6', () => expect(decodeBase64("Zm9vYmFy")).is(Bytes.of(102, 111, 111, 98, 97, 114)));
+    const d64 = (s: string) => Bytes.from(decodeBase64(s));
 
-        it('10.1b', () => expect(decodeBase64("Zg")).is(Bytes.of(102)));
-        it('10.2b', () => expect(decodeBase64("Zm8")).is(Bytes.of(102, 111)));
-        it('10.4b', () => expect(decodeBase64("Zm9vYg")).is(Bytes.of(102, 111, 111, 98)));
-        it('10.5b', () => expect(decodeBase64("Zm9vYmE")).is(Bytes.of(102, 111, 111, 98, 97)));
+    describe('RFC4648 tests', () => {
+        it('10.0', () => expect(d64("")).is(Bytes.of()));
+        it('10.1', () => expect(d64("Zg==")).is(Bytes.of(102)));
+        it('10.2', () => expect(d64("Zm8=")).is(Bytes.of(102, 111)));
+        it('10.3', () => expect(d64("Zm9v")).is(Bytes.of(102, 111, 111)));
+        it('10.4', () => expect(d64("Zm9vYg==")).is(Bytes.of(102, 111, 111, 98)));
+        it('10.5', () => expect(d64("Zm9vYmE=")).is(Bytes.of(102, 111, 111, 98, 97)));
+        it('10.6', () => expect(d64("Zm9vYmFy")).is(Bytes.of(102, 111, 111, 98, 97, 114)));
+
+        it('10.1b', () => expect(d64("Zg")).is(Bytes.of(102)));
+        it('10.2b', () => expect(d64("Zm8")).is(Bytes.of(102, 111)));
+        it('10.4b', () => expect(d64("Zm9vYg")).is(Bytes.of(102, 111, 111, 98)));
+        it('10.5b', () => expect(d64("Zm9vYmE")).is(Bytes.of(102, 111, 111, 98, 97)));
     });
 
     describe('RFC4648 examples', () => {
         it('example0', () =>
-            expect(decodeBase64('FPucA9l+')).is(Bytes.of(0x14, 0xfb, 0x9c, 0x03, 0xd9, 0x7e)));
+            expect(d64('FPucA9l+')).is(Bytes.of(0x14, 0xfb, 0x9c, 0x03, 0xd9, 0x7e)));
         it('example1', () =>
-            expect(decodeBase64('FPucA9k=')).is(Bytes.of(0x14, 0xfb, 0x9c, 0x03, 0xd9)));
+            expect(d64('FPucA9k=')).is(Bytes.of(0x14, 0xfb, 0x9c, 0x03, 0xd9)));
         it('example1b', () =>
-            expect(decodeBase64('FPucA9k')).is(Bytes.of(0x14, 0xfb, 0x9c, 0x03, 0xd9)));
+            expect(d64('FPucA9k')).is(Bytes.of(0x14, 0xfb, 0x9c, 0x03, 0xd9)));
         it('example2', () =>
-            expect(decodeBase64('FPucAw==')).is(Bytes.of(0x14, 0xfb, 0x9c, 0x03)));
+            expect(d64('FPucAw==')).is(Bytes.of(0x14, 0xfb, 0x9c, 0x03)));
         it('example2b', () =>
-            expect(decodeBase64('FPucAw=')).is(Bytes.of(0x14, 0xfb, 0x9c, 0x03)));
+            expect(d64('FPucAw=')).is(Bytes.of(0x14, 0xfb, 0x9c, 0x03)));
         it('example2c', () =>
-            expect(decodeBase64('FPucAw')).is(Bytes.of(0x14, 0xfb, 0x9c, 0x03)));
+            expect(d64('FPucAw')).is(Bytes.of(0x14, 0xfb, 0x9c, 0x03)));
     });
 
     describe('Misc test cases', () => {
-        it('gQ==', () => expect(decodeBase64('gQ==')).is(Bytes.of(0x81)));
+        it('gQ==', () => expect(d64('gQ==')).is(Bytes.of(0x81)));
     });
 });