Retry failed download requests implementation

app/test/testmerginapi.cpp

@@ -2687,7 +2687,7 @@ void TestMerginApi::deleteRemoteProjectNow( MerginApi *api, const QString &proje
   QUrl url( api->mApiRoot + QStringLiteral( "/v2/projects/%1" ).arg( projectId ) );
   request.setUrl( url );
   qDebug() << "Trying to delete project " << projectName << ", id: " << projectId << " (" << url << ")";
-  QNetworkReply *r = api->mManager.deleteResource( request );
+  QNetworkReply *r = api->mManager->deleteResource( request );
   QSignalSpy spy( r, &QNetworkReply::finished );
   spy.wait( TestUtils::SHORT_REPLY );
 
@@ -2942,3 +2942,60 @@ void TestMerginApi::testParseVersion()
   QCOMPARE( major, 2024 );
   QCOMPARE( minor, 4 );
 }
+
+void TestMerginApi::testDownloadWithNetworkError()
+{
+  QString projectName = "testDownloadRetry";
+
+  // create the project on the server (the content is not important)
+  createRemoteProject( mApiExtra, mWorkspaceName, projectName, mTestDataPath + "/" + TEST_PROJECT_NAME + "/" );
+
+  // Create mock manager - initially not failing
+  MockNetworkManager *mockManager = new MockNetworkManager( this );
+  mApi->setNetworkManager( mockManager );
+
+  // Create signal spies
+  QSignalSpy startSpy( mApi, &MerginApi::downloadItemsStarted );
+  QSignalSpy retrySpy( mApi, &MerginApi::downloadItemRetried );
+  QSignalSpy finishSpy( mApi, &MerginApi::syncProjectFinished );
+
+  // Connect to downloadItemsStarted to trigger failure when items download start
+  connect( mApi, &MerginApi::downloadItemsStarted, this, [this]()
+  {
+    MockNetworkManager *failingManager = new MockNetworkManager( this );
+    failingManager->setShouldFail( true );
+    mApi->setNetworkManager( failingManager );
+  } );
+
+  // Try to download the project
+  mApi->pullProject( mWorkspaceName, projectName );
+
+  // Verify a transaction was created
+  QCOMPARE( mApi->transactions().count(), 1 );
+
+  // Wait for the download to start and then fail
+  QVERIFY( startSpy.wait( TestUtils::LONG_REPLY ) );
+  QVERIFY( finishSpy.wait( TestUtils::LONG_REPLY ) );
+
+  // Verify signals were emitted
+  QVERIFY( startSpy.count() > 0 );
+  QVERIFY( retrySpy.count() > 0 );
+  QCOMPARE( finishSpy.count(), 1 );
+
+  // Verify that 5 (MAX_RETRY_COUNT) retry attempts were made
+  int maxRetries = TransactionStatus::MAX_RETRY_COUNT;
+  QCOMPARE( retrySpy.count(), maxRetries );
+
+  // Verify the sync failed
+  QList<QVariant> arguments = finishSpy.takeFirst();
+  QVERIFY( !arguments.at( 1 ).toBool() );
+
+  // Verify no local project was created
+  LocalProject localProject = mApi->localProjectsManager().projectFromMerginName( mWorkspaceName, projectName );
+  QVERIFY( !localProject.isValid() );
+
+  // Restore the original manager
+  QNetworkAccessManager *originalManager = new QNetworkAccessManager( this );
+  mApi->setNetworkManager( originalManager );
+}
+

app/test/testmerginapi.h

@@ -21,6 +21,68 @@
 
 #include <qgsapplication.h>
 
+class MockReply : public QNetworkReply
+{
+  public:
+    explicit MockReply( const QNetworkRequest &request, QNetworkAccessManager::Operation operation, QObject *parent = nullptr )
+      : QNetworkReply( parent )
+    {
+      setRequest( request );
+      setOperation( operation );
+      setUrl( request.url() );
+
+      setError( QNetworkReply::TimeoutError, "Mock network failure" );
+
+      QMetaObject::invokeMethod( this, "errorOccurred", Qt::QueuedConnection, Q_ARG( QNetworkReply::NetworkError, QNetworkReply::TimeoutError ) );
+      QMetaObject::invokeMethod( this, "finished", Qt::QueuedConnection );
+    }
+
+    void abort() override {}
+
+    qint64 readData( char *data, qint64 maxlen ) override
+    {
+      Q_UNUSED( data );
+      Q_UNUSED( maxlen );
+      return -1;
+    }
+
+    qint64 bytesAvailable() const override
+    {
+      return 0;
+    }
+};
+
+class MockNetworkManager : public QNetworkAccessManager
+{
+  public:
+    explicit MockNetworkManager( QObject *parent = nullptr )
+      : QNetworkAccessManager( parent )
+      , mShouldFail( false )
+    {}
+
+    void setShouldFail( bool shouldFail )
+    {
+      mShouldFail = shouldFail;
+    }
+
+    bool shouldFail() const { return mShouldFail; }
+
+  protected:
+    QNetworkReply *createRequest( Operation op, const QNetworkRequest &request, QIODevice *outgoingData = nullptr ) override
+    {
+      if ( mShouldFail )
+      {
+        MockReply *reply = new MockReply( request, op, this );
+        return reply;
+      }
+
+      return QNetworkAccessManager::createRequest( op, request, outgoingData );
+    }
+
+  private:
+    bool mShouldFail;
+};
+
 class TestMerginApi: public QObject
 {
     Q_OBJECT
@@ -40,6 +102,7 @@ class TestMerginApi: public QObject
     void testListProject();
     void testListProjectsByName();
     void testDownloadProject();
+    void testDownloadWithNetworkError();
     void testDownloadProjectSpecChars();
     void testCancelDownloadProject();
     void testCreateProjectTwice();