[DE-1103] Fix idle connection timeout in tests (#198)

Author: maciej-nedza

tests/src/test/java/com/maxio/advancedbilling/TestClientProvider.java

@@ -1,6 +1,7 @@
 package com.maxio.advancedbilling;
 
 import com.maxio.advancedbilling.authentication.BasicAuthModel;
+import okhttp3.OkHttpClient;
 
 import java.util.ArrayList;
 import java.util.List;
@@ -67,7 +68,11 @@ public static String getEnvValue(String key) {
 
     private static AdvancedBillingClient createClient(String subdomain, String apiKey) {
         return new AdvancedBillingClient.Builder()
-                .httpClientConfig(configBuilder -> configBuilder.timeout(45))
+                .httpClientConfig(configBuilder -> configBuilder
+                        .timeout(45)
+                        .httpClientInstance(
+                                new OkHttpClient.Builder().retryOnConnectionFailure(true).build()
+                        ))
                 .basicAuthCredentials(
                         new BasicAuthModel.Builder(apiKey, PASSWORD)
                                 .build())

tests/src/test/java/com/maxio/advancedbilling/controllers/sites/SitesControllerTest.java

@@ -23,10 +23,6 @@ class SitesControllerTest {
     @Test
     void shouldReadSite() throws Exception {
         // when
-        // bug: idle connection can be closed.
-        try {
-            Site site = sitesController.readSite().getSite();
-        } catch (Exception ignored) {}
         Site site = sitesController.readSite().getSite();
 
         // then