#755 added stub for TestPackageApi

src/test/java/org/gitlab4j/api/TestPackageApi.java

+package org.gitlab4j.api;
+
+import org.gitlab4j.api.models.*;
+import org.gitlab4j.api.models.Package;
+import org.junit.Before;
+import org.junit.BeforeClass;
+import org.junit.Test;
+import org.junit.experimental.categories.Category;
+
+import java.util.*;
+import static org.junit.Assert.*;
+import static org.junit.Assume.assumeNotNull;
+
+@Category(IntegrationTest.class)
+public class TestPackageApi extends AbstractIntegrationTest {
+
+    private static GitLabApi gitLabApi;
+    private static Project testProject;
+
+    public TestPackageApi() {
+        super();
+    }
+
+    @BeforeClass
+    public static void setup() {
+        gitLabApi = baseTestSetup();
+        testProject = getTestProject();
+    }
+
+    @Before
+    public void beforeMethod() {
+        assumeNotNull(gitLabApi);
+    }
+
+    @Test
+    public void getPackagesStream() throws GitLabApiException {
+        PackagesApi packagesApi = gitLabApi.getPackagesApi();
+
+        assumeNotNull(packagesApi);
+
+        Optional<Package> packageOptional = packagesApi.getPackagesStream(testProject.getId()).findAny();
+
+        assertTrue(packageOptional.isPresent());
+    }
+}