test (E2E): Create WebhooksHelper class

client/src/test/java/com/sinch/sdk/e2e/domains/WebhooksHelper.java

@@ -0,0 +1,58 @@
+package com.sinch.sdk.e2e.domains;
+
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.net.HttpURLConnection;
+import java.net.URL;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.function.Function;
+
+public class WebhooksHelper {
+
+  public static <T> Response<T> callURL(URL url, Function<String, T> parseEvent)
+      throws IOException {
+
+    HttpURLConnection con = (HttpURLConnection) url.openConnection();
+    con.setRequestMethod("GET");
+
+    ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
+
+    byte[] buffer = new byte[1024];
+    int bytesRead;
+    InputStream inputStream = con.getInputStream();
+    while ((bytesRead = inputStream.read(buffer)) != -1) {
+      byteArrayOutputStream.write(buffer, 0, bytesRead);
+    }
+    Response<T> response = new Response<>();
+    response.headers = transformHeaders(con.getHeaderFields());
+    response.rawPayload = byteArrayOutputStream.toString("UTF-8");
+    response.event = parseEvent.apply(response.rawPayload);
+    return response;
+  }
+
+  static Map<String, String> transformHeaders(Map<String, List<String>> headers) {
+    if (null == headers) {
+      return null;
+    }
+    HashMap<String, String> newMap = new HashMap<>();
+    headers.forEach((key, value) -> newMap.put(key, concatHeaderValues(value)));
+    return newMap;
+  }
+
+  static String concatHeaderValues(List<String> values) {
+    if (null == values) {
+      return null;
+    }
+    return values.stream()
+        .reduce(null, (previous, current) -> (null != previous ? previous + ";" : "") + current);
+  }
+
+  public static class Response<T> {
+    public Map<String, String> headers;
+    public String rawPayload;
+    public T event;
+  }
+}