diff --git a/test/main.cc b/test/main.cc
index 64310bf..7fcee67 100644
--- a/test/main.cc
+++ b/test/main.cc
@@ -2,18 +2,19 @@
 
 QTEST_MAIN(TestGui)
 
-void TestGui::authenticate()
+void TestGui::authenticate(MainWindow *app)
 {
-  QPushButton *change_token = app.ui->pushButton_changeToken;
+  QPushButton *change_token = app->ui->pushButton_changeToken;
   QTest::mouseClick(change_token, Qt::MouseButton::LeftButton);
-  QTest::keyClicks(app.ui->lineEdit_accessToken, "valid");
+  QTest::keyClicks(app->ui->lineEdit_accessToken, "valid");
 }
 
 void TestGui::access_token_entry_test()
 {
-  QSignalSpy auth_tries(app.canvas, &ICanvas::authenticate_done);
+  MainWindow *app = create_app();
+  QSignalSpy auth_tries(app->canvas, &ICanvas::authenticate_done);
 
-  QPushButton *change_token = app.ui->pushButton_changeToken;
+  QPushButton *change_token = app->ui->pushButton_changeToken;
 
   // click on "Change Token"
   QTest::mouseClick(change_token, Qt::MouseButton::LeftButton);
@@ -23,18 +24,19 @@ void TestGui::access_token_entry_test()
   QVERIFY(change_token->isHidden());
 
   // enter a valid token
-  QTest::keyClicks(app.ui->lineEdit_accessToken, "valid");
+  QTest::keyClicks(app->ui->lineEdit_accessToken, "valid");
 
   QCOMPARE(auth_tries.count(), 5);
 
-  QCOMPARE(app.ui->label_authenticationStatus->text(), "authenticated!");
+  QCOMPARE(app->ui->label_authenticationStatus->text(), "authenticated!");
   QVERIFY(change_token->isEnabled());
   QVERIFY(!change_token->isHidden());
 }
 
 void TestGui::fetch_courses_test()
 {
-  authenticate();
+  MainWindow *app = create_app();
+  authenticate(app);
   std::string expected[] = {
       "#0|Linear Algebra: {\n"
       "  #20010|course files: {\n"
@@ -56,15 +58,16 @@ void TestGui::fetch_courses_test()
       "  }\n"
       "}",
   };
-  for (auto t : app.course_trees)
+  for (auto t : app->course_trees)
     QCOMPARE(QString(t.to_string().c_str()), QString(expected[t.id].c_str()));
 }
 
 void TestGui::fetch_courses_ui_test()
 {
-  authenticate();
+  MainWindow *app = create_app();
+  authenticate(app);
 
-  TreeModel *model = app.ui->treeView->model();
+  TreeModel *model = app->ui->treeView->model();
   QCOMPARE(model->childrenCount(), 3);
 
   TreeIndex ptr = model->index(0, 0);
diff --git a/test/main.h b/test/main.h
index d443412..1a66075 100644
--- a/test/main.h
+++ b/test/main.h
@@ -10,23 +10,44 @@
 #include "fake_canvas.h"
 
 #include <algorithm>
+#include <filesystem>
+#include <mutex>
+#include <vector>
 
 class TestGui : public QObject
 {
   Q_OBJECT
+  int id = 1;
+  std::mutex id_mtx;
+  std::vector<QString> tmp_settings;
 
 public:
-  TestGui() : app(new FakeCanvas(), "canvas-sync-test.ini"){};
-
-  MainWindow app;
-
   // convenience routines
-  void authenticate();
+  void authenticate(MainWindow *app);
+  MainWindow *create_app()
+  {
+    return new MainWindow(new FakeCanvas(), settings_file());
+  }
+  QString settings_file()
+  {
+    this->id_mtx.lock();
+    QString result = QString("canvas-sync-test-%1.ini").arg(this->id++);
+    tmp_settings.push_back(MainWindow::settings_path + '/' + result);
+    this->id_mtx.unlock();
+    return result;
+  }
 
 private slots: // tests
   void access_token_entry_test();
   void fetch_courses_test();
   void fetch_courses_ui_test();
+  void cleanupTestCase()
+  {
+    this->id_mtx.lock();
+    for (auto i : this->tmp_settings)
+      std::filesystem::remove(i.toStdString());
+    this->id_mtx.unlock();
+  };
 };
 
 #endif