@Test
  public void testDecode_nonToken() {
    String base64Text =
        Base64.getEncoder()
            .encodeToString("something other than a JWT token".getBytes(StandardCharsets.UTF_8));
    Multimap<String, String> decoded = RegistryClient.decodeTokenRepositoryGrants(base64Text);
    Assert.assertNull(decoded);
  }
Tests for {@link RegistryClient} around handling of Docker Registry Bearer Tokens.

<p>JWTs were generated from <a href="https://jwt.io">jwt.io</a>'s <em>JWT Debugger</em>. Set the
algorithm to HS256, and paste the JSON shown as the <em>Payload</em>.
jib-core/src/test/java/com/google/cloud/tools/jib/registry/DockerRegistryBearerTokenTest.java