Add connectivity to Binance Exchange Spot Test Network endpoints.

src/main/java/com/binance/api/client/BinanceApiClientFactory.java

@@ -1,7 +1,7 @@
 package com.binance.api.client;
 
 import com.binance.api.client.impl.*;
-
+import com.binance.api.client.config.BinanceApiConfig;
 import static com.binance.api.client.impl.BinanceApiServiceGenerator.getSharedClient;
 
 /**
@@ -28,6 +28,23 @@ public class BinanceApiClientFactory {
   private BinanceApiClientFactory(String apiKey, String secret) {
     this.apiKey = apiKey;
     this.secret = secret;
+    BinanceApiConfig.useTestnet = false;
+    BinanceApiConfig.useTestnetStreaming = false;
+  }
+
+  /**
+   * Instantiates a new binance api client factory.
+   *
+   * @param apiKey the API key
+   * @param secret the Secret
+   * @param useTestnet true if endpoint is spot test network URL; false if endpoint is production spot API URL.
+   * @param useTestnetStreaming true for spot test network websocket streaming; false for no streaming.
+   */
+  private BinanceApiClientFactory(String apiKey, String secret, boolean useTestnet, boolean useTestnetStreaming) {
+      this(apiKey, secret);
+      if (useTestnet) {
+        BinanceApiConfig.useTestnet = true;
+        BinanceApiConfig.useTestnetStreaming = useTestnetStreaming; }
   }
 
   /**
@@ -42,6 +59,20 @@ public static BinanceApiClientFactory newInstance(String apiKey, String secret)
     return new BinanceApiClientFactory(apiKey, secret);
   }
 
+  /**
+   * New instance with optional Spot Test Network endpoint.
+   *
+   * @param apiKey the API key
+   * @param secret the Secret
+   * @param useTestnet true if endpoint is spot test network URL; false if endpoint is production spot API URL.
+   * @param useTestnetStreaming true for spot test network websocket streaming; false for no streaming.
+   *
+   * @return the binance api client factory.
+   */
+    public static BinanceApiClientFactory newInstance(String apiKey, String secret, boolean useTestnet, boolean useTestnetStreaming) {
+      return new BinanceApiClientFactory(apiKey, secret, useTestnet, useTestnetStreaming);
+  }
+
   /**
    * New instance without authentication.
    *
@@ -51,6 +82,18 @@ public static BinanceApiClientFactory newInstance() {
     return new BinanceApiClientFactory(null, null);
   }
 
+  /**
+   * New instance without authentication and with optional Spot Test Network endpoint.
+   *
+   * @param useTestnet true if endpoint is spot test network URL; false if endpoint is production spot API URL.
+   * @param useTestnetStreaming true for spot test network websocket streaming; false for no streaming.
+   *
+   * @return the binance api client factory.
+   */
+  public static BinanceApiClientFactory newInstance(boolean useTestnet, boolean useTestnetStreaming) {
+    return new BinanceApiClientFactory(null, null, useTestnet, useTestnetStreaming);
+  }
+
   /**
    * Creates a new synchronous/blocking REST client.
    */

src/main/java/com/binance/api/client/config/BinanceApiConfig.java

@@ -10,6 +10,23 @@ public class BinanceApiConfig {
 	 */
 	private static String BASE_DOMAIN = "binance.com";
 
+    /**
+     * Spot Test Network URL.
+     */
+    private static final String TESTNET_DOMAIN = "testnet.binance.vision";
+
+    /**
+     * Binance Spot Test Network option:
+     * true if endpoint is spot test network URL; false if endpoint is production spot API URL.
+     */
+    public static boolean useTestnet;
+
+    /**
+     * Binance Spot Test Network option:
+     * true for websocket streaming; false for no streaming.
+     */
+    public static boolean useTestnetStreaming;
+
 	/**
 	 * Set the URL base domain name (e.g., binance.com).
 	 *
@@ -49,4 +66,17 @@ public static String getAssetInfoApiBaseUrl() {
 		return String.format("https://%s/", getBaseDomain());
 	}
 
+    /**
+     * Spot Test Network API base URL.
+     */
+    public static String getTestNetBaseUrl() {
+		return String.format("https://%s", TESTNET_DOMAIN);
+    }
+
+    /**
+     * Streaming Spot Test Network base URL.
+     */
+    public static String getStreamTestNetBaseUrl() {
+        return String.format("wss://%s", TESTNET_DOMAIN);
+    }
 }

src/main/java/com/binance/api/client/impl/BinanceApiServiceGenerator.java

@@ -45,9 +45,26 @@ public static <S> S createService(Class<S> serviceClass) {
         return createService(serviceClass, null, null);
     }
 
+    /**
+     * Create a Binance API service.
+     *
+     * @param serviceClass the type of service.
+     * @param apiKey Binance API key.
+     * @param secret Binance secret.
+     *
+     * @return a new implementation of the API endpoints for the Binance API service.
+     */
     public static <S> S createService(Class<S> serviceClass, String apiKey, String secret) {
+        String baseUrl = null;
+        if (!BinanceApiConfig.useTestnet) { baseUrl = BinanceApiConfig.getApiBaseUrl(); }
+        else {
+            baseUrl = BinanceApiConfig.useTestnetStreaming ?
+                BinanceApiConfig.getStreamTestNetBaseUrl() :
+                BinanceApiConfig.getTestNetBaseUrl();
+        }
+
         Retrofit.Builder retrofitBuilder = new Retrofit.Builder()
-                .baseUrl(BinanceApiConfig.getApiBaseUrl())
+                .baseUrl(baseUrl)
                 .addConverterFactory(converterFactory);
 
         if (StringUtils.isEmpty(apiKey) || StringUtils.isEmpty(secret)) {