Fix project download bug reported by @barreeeiroo

Change-Id: Ibe01541a106b37bffbde21f05ea7f1b2c134070a

appinventor/appengine/src/com/google/appinventor/server/AdminInfoServiceImpl.java

 // -*- mode: java; c-basic-offset: 2; -*-
-// Copyright 2015 MIT, All rights reserved
+// Copyright 2015-2019 MIT, All rights reserved
 // Released under the Apache License, Version 2.0
 // http://www.apache.org/licenses/LICENSE-2.0
 
@@ -33,7 +33,7 @@ import com.google.appinventor.server.util.PasswordHash;
 public class AdminInfoServiceImpl extends OdeRemoteServiceServlet implements AdminInfoService {
 
   // Storage of user settings
-  private final transient StorageIo storageIo = StorageIoInstanceHolder.INSTANCE;
+  private final transient StorageIo storageIo = StorageIoInstanceHolder.getInstance();
 
   /**
    * Returns a list of AdminUsers, up to 20, based on the starting

appinventor/appengine/src/com/google/appinventor/server/AndroidServlet.java

 // -*- mode: java; c-basic-offset: 2; -*-
 // Copyright 2009-2011 Google, All Rights reserved
-// Copyright 2011-2012 MIT, All rights reserved
+// Copyright 2011-2019 MIT, All rights reserved
 // Released under the Apache License, Version 2.0
 // http://www.apache.org/licenses/LICENSE-2.0
 
@@ -33,7 +33,7 @@ public class AndroidServlet extends OdeServlet {
   // Content type for response header (to avoid security vulnerabilities)
   private static final String CONTENT_TYPE = "text/html; charset=utf-8";
 
-  private final StorageIo storageIo = StorageIoInstanceHolder.INSTANCE;
+  private final StorageIo storageIo = StorageIoInstanceHolder.getInstance();
 
   @Override
   public void doGet(HttpServletRequest req, HttpServletResponse resp) throws IOException {

appinventor/appengine/src/com/google/appinventor/server/BlobUpgradeServlet.java

 // -*- mode: java; c-basic-offset: 2; -*-
-// Copyright 2015 MIT, All rights reserved
+// Copyright 2015-2019 MIT, All rights reserved
 // Released under the Apache License, Version 2.0
 // http://www.apache.org/licenses/LICENSE-2.0
 
@@ -39,7 +39,7 @@ public class BlobUpgradeServlet extends OdeServlet {
   // Logging support
   private static final Logger LOG = Logger.getLogger(BlobUpgradeServlet.class.getName());
   private static final CapabilitiesService caps = CapabilitiesServiceFactory.getCapabilitiesService();
-  private final StorageIo storageIo = StorageIoInstanceHolder.INSTANCE;
+  private final StorageIo storageIo = StorageIoInstanceHolder.getInstance();
 
   @Override
   public void doPost(HttpServletRequest req, HttpServletResponse resp)

appinventor/appengine/src/com/google/appinventor/server/BuildOutputServlet.java

 // -*- mode: java; c-basic-offset: 2; -*-
 // Copyright 2009-2011 Google, All Rights reserved
-// Copyright 2011-2013 MIT, All rights reserved
+// Copyright 2011-2019 MIT, All rights reserved
 // Released under the Apache License, Version 2.0
 // http://www.apache.org/licenses/LICENSE-2.0
 
@@ -48,7 +48,7 @@ public class BuildOutputServlet extends OdeServlet {
 
   private final FileExporter fileExporter = new FileExporterImpl();
 
-  private final StorageIo storageIo = StorageIoInstanceHolder.INSTANCE;
+  private final StorageIo storageIo = StorageIoInstanceHolder.getInstance();
 
   @Override
   public void doGet(HttpServletRequest req, HttpServletResponse resp) throws IOException {

appinventor/appengine/src/com/google/appinventor/server/ComponentServiceImpl.java

 // -*- mode: java; c-basic-offset: 2; -*-
-// Copyright 2015-2017 MIT, All rights reserved
+// Copyright 2015-2019 MIT, All rights reserved
 // Released under the Apache License, Version 2.0
 // http://www.apache.org/licenses/LICENSE-2.0
 
@@ -49,7 +49,7 @@ public class ComponentServiceImpl extends OdeRemoteServiceServlet
   private static final Logger LOG =
       Logger.getLogger(ComponentServiceImpl.class.getName());
 
-  private final transient StorageIo storageIo = StorageIoInstanceHolder.INSTANCE;
+  private final transient StorageIo storageIo = StorageIoInstanceHolder.getInstance();
 
   private final FileImporter fileImporter = new FileImporterImpl();
 

appinventor/appengine/src/com/google/appinventor/server/DownloadServlet.java

 // -*- mode: java; c-basic-offset: 2; -*-
 // Copyright 2009-2011 Google, All Rights reserved
-// Copyright 2011-2012 MIT, All rights reserved
+// Copyright 2011-2019 MIT, All rights reserved
 // Released under the Apache License, Version 2.0
 // http://www.apache.org/licenses/LICENSE-2.0
 
@@ -126,6 +126,7 @@ public class DownloadServlet extends OdeServlet {
         // project in the export
         boolean includeYail = userInfoProvider.getIsAdmin();
         boolean includeScreenShots = includeYail;
+        StorageIoInstanceHolder.getInstance().assertUserHasProject(userId, projectId);
         ProjectSourceZip zipFile = fileExporter.exportProjectSourceZip(userId,
           projectId, includeProjectHistory, false, zipName, includeYail,
           includeScreenShots, false, false);
@@ -141,7 +142,7 @@ public class DownloadServlet extends OdeServlet {
 
         String userIdOrEmail = uriComponents[USER_PROJECT_USERID_INDEX];
         String projectUserId;
-        StorageIo storageIo = StorageIoInstanceHolder.INSTANCE;
+        StorageIo storageIo = StorageIoInstanceHolder.getInstance();
         if (userIdOrEmail.contains("@")) {
           // email address
           try {
@@ -215,6 +216,17 @@ public class DownloadServlet extends OdeServlet {
       }
     } catch (IllegalArgumentException e) {
       throw CrashReport.createAndLogError(LOG, req, "user=" + userId, e);
+    } catch (SecurityException e) {
+      // Not having appropriate permission is akin to not being able to find the project anyway,
+      // so we use 404 here to not leak that the project may exist.
+      final String message = "404 Not Found";
+      resp.setStatus(HttpServletResponse.SC_NOT_FOUND);
+      resp.setContentType("text/plain");
+      resp.setContentLength(message.length());
+      ServletOutputStream out = resp.getOutputStream();
+      out.write(message.getBytes());
+      out.close();
+      return;
     }
 
     String fileName = downloadableFile.getFileName();

appinventor/appengine/src/com/google/appinventor/server/FeedbackServlet.java

 // -*- mode: java; c-basic-offset: 2; -*-
 // Copyright 2009-2011 Google, All Rights reserved
-// Copyright 2011-2013 MIT, All rights reserved
+// Copyright 2011-2019 MIT, All rights reserved
 // Released under the Apache License, Version 2.0
 // http://www.apache.org/licenses/LICENSE-2.0
 
@@ -35,7 +35,7 @@ public class FeedbackServlet extends OdeServlet {
   private static final Logger LOG = Logger.getLogger(ReceiveBuildServlet.class.getName());
 
   private final OdeAuthFilter odeFilter = new OdeAuthFilter();
-  private final transient StorageIo storageIo = StorageIoInstanceHolder.INSTANCE;
+  private final transient StorageIo storageIo = StorageIoInstanceHolder.getInstance();
 
   @Override
   public void doGet(HttpServletRequest req, HttpServletResponse resp) throws IOException {

appinventor/appengine/src/com/google/appinventor/server/FileExporterImpl.java

 // -*- mode: java; c-basic-offset: 2; -*-
 // Copyright 2009-2011 Google, All Rights reserved
-// Copyright 2011-2012 MIT, All rights reserved
+// Copyright 2011-2019 MIT, All rights reserved
 // Released under the Apache License, Version 2.0
 // http://www.apache.org/licenses/LICENSE-2.0
 
@@ -30,7 +30,7 @@ import javax.annotation.Nullable;
  */
 public final class FileExporterImpl implements FileExporter {
 
-  private final StorageIo storageIo = StorageIoInstanceHolder.INSTANCE;
+  private final StorageIo storageIo = StorageIoInstanceHolder.getInstance();
 
   @Override
   public RawFile exportProjectOutputFile(String userId, long projectId, @Nullable String target)

appinventor/appengine/src/com/google/appinventor/server/FileImporterImpl.java

 // -*- mode: java; c-basic-offset: 2; -*-
 // Copyright 2009-2011 Google, All Rights reserved
-// Copyright 2011-2017 MIT, All rights reserved
+// Copyright 2011-2019 MIT, All rights reserved
 // Released under the Apache License, Version 2.0
 // http://www.apache.org/licenses/LICENSE-2.0
 
@@ -51,7 +51,7 @@ public final class FileImporterImpl implements FileImporter {
 
   private static final Logger LOG = Logger.getLogger(FileImporterImpl.class.getName());
 
-  private final StorageIo storageIo = StorageIoInstanceHolder.INSTANCE;
+  private final StorageIo storageIo = StorageIoInstanceHolder.getInstance();
 
   @Override
   public UserProject importProject(String userId, String projectName,

appinventor/appengine/src/com/google/appinventor/server/GetMotdServiceImpl.java

 // -*- mode: java; c-basic-offset: 2; -*-
 // Copyright 2009-2011 Google, All Rights reserved
-// Copyright 2011-2012 MIT, All rights reserved
+// Copyright 2011-2019 MIT, All rights reserved
 // Released under the Apache License, Version 2.0
 // http://www.apache.org/licenses/LICENSE-2.0
 
@@ -35,7 +35,7 @@ public class GetMotdServiceImpl extends OdeRemoteServiceServlet implements GetMo
   private static final Flag<Integer> motdCheckIntervalSecs =
     Flag.createFlag("motd.check.interval.secs", 300);
 
-  private final StorageIo storageIo = StorageIoInstanceHolder.INSTANCE;
+  private final StorageIo storageIo = StorageIoInstanceHolder.getInstance();
 
   private final MemcacheService memcache = MemcacheServiceFactory.getMemcacheService();
 

appinventor/appengine/src/com/google/appinventor/server/LoginServlet.java

 // -*- mode: java; c-basic-offset: 2; -*-
 // Copyright 2009-2011 Google, All Rights reserved
-// Copyright 2011-2014 MIT, All rights reserved
+// Copyright 2011-2019 MIT, All rights reserved
 // Released under the MIT License https://raw.github.com/mit-cml/app-inventor/master/mitlicense.txt
 
 package com.google.appinventor.server;
@@ -65,7 +65,7 @@ import org.owasp.html.PolicyFactory;
 @SuppressWarnings("unchecked")
 public class LoginServlet extends HttpServlet {
 
-  private final StorageIo storageIo = StorageIoInstanceHolder.INSTANCE;
+  private final StorageIo storageIo = StorageIoInstanceHolder.getInstance();
   private static final Logger LOG = Logger.getLogger(LoginServlet.class.getName());
   private static final Flag<String> mailServer = Flag.createFlag("localauth.mailserver", "");
   private static final Flag<String> password = Flag.createFlag("localauth.mailserver.password", "");

appinventor/appengine/src/com/google/appinventor/server/OdeAuthFilter.java

 // -*- mode: java; c-basic-offset: 2; -*-
 // Copyright 2009-2011 Google, All Rights reserved
-// Copyright 2011-2012 MIT, All rights reserved
+// Copyright 2011-2019 MIT, All rights reserved
 // Released under the Apache License, Version 2.0
 // http://www.apache.org/licenses/LICENSE-2.0
 
@@ -56,7 +56,7 @@ public class OdeAuthFilter implements Filter {
   private static Crypter crypter = null; // accessed through getCrypter only
   private static final Object crypterSync = new Object();
 
-  private final StorageIo storageIo = StorageIoInstanceHolder.INSTANCE;
+  private final StorageIo storageIo = StorageIoInstanceHolder.getInstance();
 
   // Whether this server should use a whitelist to determine who can
   // access it. Value is specified in the <system-properties> section

appinventor/appengine/src/com/google/appinventor/server/ProjectServiceImpl.java

 // -*- mode: java; c-basic-offset: 2; -*-
 // Copyright 2009-2011 Google, All Rights reserved
-// Copyright 2011-2017 MIT, All rights reserved
+// Copyright 2011-2019 MIT, All rights reserved
 // Released under the Apache License, Version 2.0
 // http://www.apache.org/licenses/LICENSE-2.0
 
@@ -59,7 +59,7 @@ public class ProjectServiceImpl extends OdeRemoteServiceServlet implements Proje
 
   private static final long serialVersionUID = -8316312003804169166L;
 
-  private final transient StorageIo storageIo = StorageIoInstanceHolder.INSTANCE;
+  private final transient StorageIo storageIo = StorageIoInstanceHolder.getInstance();
 
   // RPC implementation for YoungAndroid projects
   private final transient YoungAndroidProjectService youngAndroidProject =

appinventor/appengine/src/com/google/appinventor/server/ReceiveBuildServlet.java

 // -*- mode: java; c-basic-offset: 2; -*-
 // Copyright 2009-2011 Google, All Rights reserved
-// Copyright 2011-2012 MIT, All rights reserved
+// Copyright 2011-2019 MIT, All rights reserved
 // Released under the Apache License, Version 2.0
 // http://www.apache.org/licenses/LICENSE-2.0
 
@@ -37,7 +37,7 @@ public class ReceiveBuildServlet extends OdeServlet {
   private static final Logger LOG = Logger.getLogger(ReceiveBuildServlet.class.getName());
 
   private final OdeAuthFilter odeFilter = new OdeAuthFilter();
-  private final transient StorageIo storageIo = StorageIoInstanceHolder.INSTANCE;
+  private final transient StorageIo storageIo = StorageIoInstanceHolder.getInstance();
 
   @Override
   public void doPost(HttpServletRequest req, HttpServletResponse resp) throws IOException {

appinventor/appengine/src/com/google/appinventor/server/RendezvousServlet.java

 // -*- mode: java; c-basic-offset: 2; -*-
 // Copyright 2009-2011 Google, All Rights reserved
-// Copyright 2011-2012 MIT, All rights reserved
+// Copyright 2011-2019 MIT, All rights reserved
 // Released under the Apache License, Version 2.0
 // http://www.apache.org/licenses/LICENSE-2.0
 
@@ -101,7 +101,7 @@ public class RendezvousServlet extends HttpServlet {
 
   private final String rendezvousuuid = "c96d8ac6-e571-48bb-9e1f-58df18574e43"; // UUID Generated by JIS
 
-  private final StorageIo storageIo = StorageIoInstanceHolder.INSTANCE;
+  private final StorageIo storageIo = StorageIoInstanceHolder.getInstance();
 
   public void init(ServletConfig config) throws ServletException {
     super.init(config);

appinventor/appengine/src/com/google/appinventor/server/TosServlet.java

@@ -28,7 +28,7 @@ public class TosServlet extends OdeServlet {
   // Logging support
   private static final Logger LOG = Logger.getLogger(TosServlet.class.getName());
 
-  private final StorageIo storageIo = StorageIoInstanceHolder.INSTANCE;
+  private final StorageIo storageIo = StorageIoInstanceHolder.getInstance();
   private static final long serialVersionUID = 8099788377554316289L;
 
   // An URL to redirect requests to the first time they access App Inventor.

appinventor/appengine/src/com/google/appinventor/server/UserInfoServiceImpl.java

 // -*- mode: java; c-basic-offset: 2; -*-
 // Copyright 2009-2011 Google, All Rights reserved
-// Copyright 2011-2012 MIT, All rights reserved
+// Copyright 2011-2019 MIT, All rights reserved
 // Released under the Apache License, Version 2.0
 // http://www.apache.org/licenses/LICENSE-2.0
 
@@ -24,7 +24,7 @@ import com.google.appinventor.shared.storage.StorageUtil;
 public class UserInfoServiceImpl extends OdeRemoteServiceServlet implements UserInfoService {
 
   // Storage of user settings
-  private final transient StorageIo storageIo = StorageIoInstanceHolder.INSTANCE;
+  private final transient StorageIo storageIo = StorageIoInstanceHolder.getInstance();
 
   private static final long serialVersionUID = -7316312435338169166L;
 

appinventor/appengine/src/com/google/appinventor/server/storage/ObjectifyGalleryStorageIo.java

 // -*- mode: java; c-basic-offset: 2; -*-
 // Copyright 2009-2011 Google, All Rights reserved
-// Copyright 2011-2012 MIT, All rights reserved
+// Copyright 2011-2019 MIT, All rights reserved
 // Released under the Apache License, Version 2.0
 // http://www.apache.org/licenses/LICENSE-2.0
 
@@ -91,7 +91,7 @@ public class ObjectifyGalleryStorageIo implements  GalleryStorageIo {
 
   // we'll need to talk to the StorageIo to get developer names, so...
   private final transient StorageIo storageIo =
-      StorageIoInstanceHolder.INSTANCE;
+      StorageIoInstanceHolder.getInstance();
 
   /**
    * creates a new gallery app

appinventor/appengine/src/com/google/appinventor/server/storage/ObjectifyStorageIo.java

 // -*- mode: java; c-basic-offset: 2; -*-
 // Copyright 2009-2011 Google, All Rights reserved
-// Copyright 2011-2012 MIT, All rights reserved
+// Copyright 2011-2019 MIT, All rights reserved
 // Released under the Apache License, Version 2.0
 // http://www.apache.org/licenses/LICENSE-2.0
 
@@ -2941,4 +2941,25 @@ public class ObjectifyStorageIo implements  StorageIo {
       return ival.intValue();
     }
   }
+
+  @Override
+  public void assertUserHasProject(final String userId, final long projectId) {
+    try {
+      runJobWithRetries(new JobRetryHelper() {
+        @SuppressWarnings("RedundantThrows")
+        @Override
+        public void run(Objectify datastore) throws ObjectifyException, IOException {
+          Key<UserData> userKey = userKey(userId);
+          Key<UserProjectData> userProjectKey = userProjectKey(userKey, projectId);
+          UserProjectData data = datastore.find(userProjectKey);
+          if (data == null) {  // User doesn't have the corresponding project.
+            throw new SecurityException("Unauthorized access");
+          }
+          // User has data for project, so everything checks out.
+        }
+      }, false);
+    } catch(ObjectifyException e) {
+      throw CrashReport.createAndLogError(LOG, null, null, e);
+    }
+  }
 }

appinventor/appengine/src/com/google/appinventor/server/storage/StorageIo.java

 // -*- mode: java; c-basic-offset: 2; -*-
 // Copyright 2009-2011 Google, All Rights reserved
-// Copyright 2011-2012 MIT, All rights reserved
+// Copyright 2011-2019 MIT, All rights reserved
 // Released under the Apache License, Version 2.0
 // http://www.apache.org/licenses/LICENSE-2.0
 
@@ -706,4 +706,15 @@ public interface StorageIo {
 
   public int getBuildStatus(String userId, long projectId);
 
+  /**
+   * Checks that the user identified by {@code userId} has a reference to the project identified
+   * by {@code projectId}. If a corresponding UserProjectData is not found, this function throws
+   * a SecurityException to indicate unauthorized access.
+   *
+   * @param userId id for the user
+   * @param projectId id for the project
+   * @throws SecurityException if the user doesn't have access to the project
+   */
+  void assertUserHasProject(String userId, long projectId);
+
 }

appinventor/appengine/src/com/google/appinventor/server/storage/StorageIoInstanceHolder.java

 // -*- mode: java; c-basic-offset: 2; -*-
 // Copyright 2009-2011 Google, All Rights reserved
-// Copyright 2011-2012 MIT, All rights reserved
+// Copyright 2011-2019 MIT, All rights reserved
 // Released under the Apache License, Version 2.0
 // http://www.apache.org/licenses/LICENSE-2.0
 
 package com.google.appinventor.server.storage;
 
+import com.google.common.annotations.VisibleForTesting;
+
 /**
  * Holds the singleton StorageIo subclass object. We introduce this class
  * so that we can switch out the underlying StorageIo subclass without changing
@@ -15,8 +17,19 @@ package com.google.appinventor.server.storage;
  *
  */
 public class StorageIoInstanceHolder {
-  public static final StorageIo INSTANCE = new ObjectifyStorageIo();
+  private static StorageIo INSTANCE;
   
   private StorageIoInstanceHolder() {} // not to be instantiated
 
+  public static StorageIo getInstance() {
+    if (INSTANCE == null) {
+      INSTANCE = new ObjectifyStorageIo();
+    }
+    return INSTANCE;
+  }
+
+  @VisibleForTesting
+  public static void setInstance(StorageIo instance) {
+    INSTANCE = instance;
+  }
 }

appinventor/appengine/tests/com/google/appinventor/server/ComponentServiceTest.java

 // -*- mode: java; c-basic-offset: 2; -*-
-// Copyright 2017 MIT, All rights reserved
+// Copyright 2017-2019 MIT, All rights reserved
 // Released under the Apache License, Version 2.0
 // http://www.apache.org/licenses/LICENSE-2.0
 
@@ -316,7 +316,8 @@ public class ComponentServiceTest {
   }
 
   private void assertAssetsWithPrefixRemoved(String prefix) {
-    List<String> files = StorageIoInstanceHolder.INSTANCE.getProjectSourceFiles("1", projectId);
+    List<String> files = StorageIoInstanceHolder.getInstance()
+        .getProjectSourceFiles("1", projectId);
     for (String name : files) {
       if (name.startsWith(prefix)) {
         fail("Expected for file " + name + " to be deleted.");
@@ -325,7 +326,8 @@ public class ComponentServiceTest {
   }
 
   private void assertAssetsOnServer(String path) {
-    List<String> files = StorageIoInstanceHolder.INSTANCE.getProjectSourceFiles("1", projectId);
+    List<String> files = StorageIoInstanceHolder.getInstance()
+        .getProjectSourceFiles("1", projectId);
     for (String name : files) {
       if (name.equals(path)) {
         return;

appinventor/appengine/tests/com/google/appinventor/server/DownloadServletTest.java

 // -*- mode: java; c-basic-offset: 2; -*-
 // Copyright 2009-2011 Google, All Rights reserved
-// Copyright 2011-2012 MIT, All rights reserved
+// Copyright 2011-2019 MIT, All rights reserved
 // Released under the Apache License, Version 2.0
 // http://www.apache.org/licenses/LICENSE-2.0
 
 package com.google.appinventor.server;
 
+import com.google.appinventor.server.storage.StorageIo;
+import com.google.appinventor.server.storage.StorageIoInstanceHolder;
 import com.google.appinventor.shared.rpc.project.ProjectSourceZip;
 import com.google.appinventor.shared.rpc.project.RawFile;
 import com.riq.MockHttpServletRequest;
@@ -17,6 +19,7 @@ import org.powermock.api.easymock.PowerMock;
 import org.powermock.core.classloader.annotations.PrepareForTest;
 import org.powermock.modules.junit4.PowerMockRunner;
 
+import javax.servlet.http.HttpServletResponse;
 import java.io.IOException;
 import java.util.List;
 
@@ -50,6 +53,7 @@ public class DownloadServletTest {
 
   private FileExporterImpl exporterMock;
   private LocalUser localUserMock;
+  private StorageIo storageIoMock;
 
   @Before
   public void setUp() throws Exception {
@@ -60,6 +64,9 @@ public class DownloadServletTest {
     exporterMock = PowerMock.createNiceMock(FileExporterImpl.class);
     PowerMock.expectNew(FileExporterImpl.class).andReturn(exporterMock).anyTimes();
 
+    storageIoMock = PowerMock.createNiceMock(StorageIo.class);
+    StorageIoInstanceHolder.setInstance(storageIoMock);
+
     dummyZip = new ProjectSourceZip(DUMMY_ZIP_FILENAME, new byte[] {}, 2);
     dummyZipWithTitle = new ProjectSourceZip(DUMMY_ZIP_FILENAME_WITH_TITLE, new byte[] {}, 2);
     dummyApk = new RawFile(DUMMY_APK_FILENAME, new byte[] {});
@@ -74,6 +81,8 @@ public class DownloadServletTest {
 
   @Test
   public void testDownloadProjectSourceZipWithoutTitle() throws Exception {
+    storageIoMock.assertUserHasProject(USER_ID, PROJECT_ID);
+    PowerMock.expectLastCall().once();
     MockHttpServletRequest request = new MockHttpServletRequest(DOWNLOAD_URL +
         "project-source/1234");
     expect(exporterMock.exportProjectSourceZip(USER_ID, PROJECT_ID, true, false, null, false, false, false, false))
@@ -89,6 +98,8 @@ public class DownloadServletTest {
 
   @Test
   public void testDownloadProjectSourceZipWithTitle() throws IOException {
+    storageIoMock.assertUserHasProject(USER_ID, PROJECT_ID);
+    PowerMock.expectLastCall().once();
     MockHttpServletRequest request = new MockHttpServletRequest(DOWNLOAD_URL +
         "project-source/1234/My Project Title 123");
     expect(exporterMock.exportProjectSourceZip(USER_ID, PROJECT_ID, true, false,
@@ -105,20 +116,15 @@ public class DownloadServletTest {
 
   @Test
   public void testDownloadProjectSourceZipWithNonExistingProject() throws IOException {
-    IllegalArgumentException expectedException = new IllegalArgumentException();
+    storageIoMock.assertUserHasProject(USER_ID, 12345L);
+    PowerMock.expectLastCall().andThrow(new SecurityException());
+    PowerMock.replayAll();
     MockHttpServletRequest request = new MockHttpServletRequest(DOWNLOAD_URL +
         "project-source/12345");
-    expect(exporterMock.exportProjectSourceZip(USER_ID, 12345L, true, false, null, false, false, false, false))
-        .andThrow(expectedException);
-    PowerMock.replayAll();
     DownloadServlet download = new DownloadServlet();
-    try {
-      download.doGet(request, new MockHttpServletResponse());
-      fail();
-    } catch (IllegalArgumentException ex) {
-      assertEquals(expectedException, ex);
-    }
-    PowerMock.verifyAll();
+    MockHttpServletResponse response = new MockHttpServletResponse();
+    download.doGet(request, response);
+    assertEquals(HttpServletResponse.SC_NOT_FOUND, response.getStatus());
   }
 
   @Test

appinventor/appengine/tests/com/google/appinventor/server/FileExporterImplTest.java

 // -*- mode: java; c-basic-offset: 2; -*-
 // Copyright 2009-2011 Google, All Rights reserved
-// Copyright 2011-2012 MIT, All rights reserved
+// Copyright 2011-2019 MIT, All rights reserved
 // Released under the Apache License, Version 2.0
 // http://www.apache.org/licenses/LICENSE-2.0
 
@@ -58,7 +58,7 @@ public class FileExporterImplTest extends LocalDatastoreTestCase {
   @Override
   protected void setUp() throws Exception {
     super.setUp();
-    storageIo = StorageIoInstanceHolder.INSTANCE;
+    storageIo = StorageIoInstanceHolder.getInstance();
     exporter = new FileExporterImpl();
     Project project = new Project(PROJECT_NAME);
     project.setProjectType(FAKE_PROJECT_TYPE);

appinventor/appengine/tests/com/google/appinventor/server/FileImporterImplTest.java

 // -*- mode: java; c-basic-offset: 2; -*-
 // Copyright 2009-2011 Google, All Rights reserved
-// Copyright 2011-2012 MIT, All rights reserved
+// Copyright 2011-2019 MIT, All rights reserved
 // Released under the Apache License, Version 2.0
 // http://www.apache.org/licenses/LICENSE-2.0
 
@@ -43,7 +43,7 @@ public class FileImporterImplTest extends LocalDatastoreTestCase {
   @Override
   protected void setUp() throws Exception {
     super.setUp();
-    storageIo = StorageIoInstanceHolder.INSTANCE;
+    storageIo = StorageIoInstanceHolder.getInstance();
     // Create user with given parameters
     storageIo.getUser(USER_ID, USER_EMAIL_ADDRESS);
     fileImporter = new FileImporterImpl();

appinventor/appengine/tests/com/google/appinventor/server/ProjectServiceTest.java

 // -*- mode: java; c-basic-offset: 2; -*-
 // Copyright 2009-2011 Google, All Rights reserved
-// Copyright 2011-2017 MIT, All rights reserved
+// Copyright 2011-2019 MIT, All rights reserved
 // Released under the Apache License, Version 2.0
 // http://www.apache.org/licenses/LICENSE-2.0
 
@@ -103,7 +103,7 @@ public class ProjectServiceTest {
   @Before
   public void setUp() throws Exception {
     helper.setUp();
-    storageIo = StorageIoInstanceHolder.INSTANCE;
+    storageIo = StorageIoInstanceHolder.getInstance();
 
     PowerMock.mockStatic(LocalUser.class);
     localUserMock = PowerMock.createMock(LocalUser.class);