add test for reverse proxy configuration

commercetools/commercetools-sdk-java-api/src/test/java/com/commercetools/ReverseProxyTest.java

@@ -0,0 +1,46 @@
+
+package com.commercetools;
+
+import java.nio.charset.StandardCharsets;
+import java.util.concurrent.CompletableFuture;
+
+import com.commercetools.api.client.ProjectApiRoot;
+import com.commercetools.api.defaultconfig.ApiRootBuilder;
+
+import io.vrap.rmf.base.client.ApiHttpRequest;
+import io.vrap.rmf.base.client.ApiHttpResponse;
+import io.vrap.rmf.base.client.VrapHttpClient;
+import io.vrap.rmf.base.client.oauth2.ClientCredentials;
+
+import org.assertj.core.api.Assertions;
+import org.junit.jupiter.api.Test;
+
+public class ReverseProxyTest {
+
+    static class TestClient implements VrapHttpClient {
+        private ApiHttpRequest request;
+        @Override
+        public CompletableFuture<ApiHttpResponse<byte[]>> execute(ApiHttpRequest request) {
+            this.request = request;
+            return CompletableFuture
+                    .completedFuture(new ApiHttpResponse<>(200, null, "{}".getBytes(StandardCharsets.UTF_8)));
+        }
+
+        public ApiHttpRequest getRequest() {
+            return request;
+        }
+    }
+    @Test
+    public void reverseProxy() {
+        TestClient client = new TestClient();
+        ProjectApiRoot apiRoot = ApiRootBuilder.of(client)
+                .defaultClient(ClientCredentials.of().withClientId("").withClientSecret("").build(),
+                    "https://auth.europe-west1.gcp.commercetools.com/oauth/token", "https://myapi.example.com/api/v1/")
+                .build("test");
+
+        apiRoot.carts().get().executeBlocking();
+
+        ApiHttpRequest request = client.getRequest();
+        Assertions.assertThat(request.getUri().toString()).isEqualTo("https://myapi.example.com/api/v1/test/carts");
+    }
+}