@Test
public void testNullRequest() {

    final String signature = "SSSSIGNATURE";
    final byte[] nullContent = "null".getBytes(StandardCharsets.UTF_8);
    when(signatureValidator.validateSignature(nullContent, signature)).thenReturn(true);
    assertThatThrownBy(() -> parser.handle(signature, nullContent))
            .isInstanceOf(WebhookParseException.class)
            .hasMessage("Invalid content");
}