@Test
public void generateSignature() throws Exception {

    LineSignatureValidator lineSignatureValidator = new LineSignatureValidator(
            channelSecret.getBytes(StandardCharsets.UTF_8));
    String httpRequestBody = "{}";
    byte[] headerSignature = lineSignatureValidator
            .generateSignature(httpRequestBody.getBytes(StandardCharsets.UTF_8));
    assertThat(Base64Utils.encodeToString(headerSignature))
            .isEqualTo("3q8QXTAGaey18yL8FWTqdVlbMr6hcuNvM4tefa0o9nA=");
}