private String getResourcePath(String res) {
        URL resource = CAMutualAuthTest.class.getResource(res);
        try {
            return Paths.get(resource.toURI()).toFile().getAbsolutePath();
        } catch (URISyntaxException e) {
            throw new RuntimeException(e);
        }
    }
Scenario:
  - CA is only in API trust store, missing from gateway trust store
  - Gateway does not trust API, as it does not trust CA
  - API trusts gateway via CA
gateway/platforms/servlet/src/test/java/io/apiman/gateway/platforms/servlet/auth/tls/CAMutualAuthTest.java