tests/query_tests: Run unit tests without GUI

- Take advantage of the new, more compartmentalized OpenShotApp class,
  and run the unit tests without creating the application GUI at all.
- Unit tests can even be run headless by selecting a platform
  plugin with no display requirements on the command line, e.g.:
  `python3 tests/query_tests.py --platform minimal`
  `python3 tests/query_tests.py --platform offscreen`

Author: ferdnyc

src/tests/query_tests.py

@@ -25,20 +25,33 @@
  along with OpenShot Library.  If not, see <http://www.gnu.org/licenses/>.
  """
 
-import sys, os
+import sys
+import os
+import random
+import unittest
+import uuid
+import json
+
+import openshot
+
+from PyQt5.QtGui import QGuiApplication
+try:
+    # QtWebEngineWidgets must be loaded prior to creating a QApplication
+    # But on systems with only WebKit, this will fail (and we ignore the failure)
+    from PyQt5.QtWebEngineWidgets import QWebEngineView
+except ImportError:
+    pass
+
 # Import parent folder (so it can find other imports)
 PATH = os.path.dirname(os.path.dirname(os.path.realpath(__file__)))
 if PATH not in sys.path:
     sys.path.append(PATH)
 
-import random
-import unittest
-import uuid
-from PyQt5.QtGui import QGuiApplication
 from classes.app import OpenShotApp
 from classes import info
-import openshot  # Python module for libopenshot (required video editing module installed separately)
-import json
+
+
+app = None
 
 class TestQueryClass(unittest.TestCase):
     """ Unit test class for Query class """
@@ -47,7 +60,7 @@ class TestQueryClass(unittest.TestCase):
     def setUpClass(TestQueryClass):
         """ Init unit test data """
         # Create Qt application
-        TestQueryClass.app = OpenShotApp([], mode="unittest")
+        TestQueryClass.app = QGuiApplication.instance()
         TestQueryClass.clip_ids = []
         TestQueryClass.file_ids = []
         TestQueryClass.transition_ids = []
@@ -106,8 +119,7 @@ def setUpClass(TestQueryClass):
     @classmethod
     def tearDownClass(cls):
         "Hook method for deconstructing the class fixture after running all tests in the class."
-        print ('Exiting Unittests: Quitting QApplication')
-        TestQueryClass.app.window.actionQuit.trigger()
+        TestQueryClass.app.quit()
 
     def test_add_clip(self):
         """ Test the Clip.save method by adding multiple clips """
@@ -318,6 +330,19 @@ def test_add_file(self):
         self.assertEqual(len(File.filter()), num_files + 1)
 
 
-if __name__ == '__main__':
-    app = QGuiApplication(sys.argv)
+def main():
+    global app
+    info.LOG_LEVEL_CONSOLE = "ERROR"
+    try:
+        app = OpenShotApp(sys.argv, mode="unittest")
+    except Exception:
+        from logging import logger
+        log = logger.getlog(".")
+        log.error("Failed to instantiate OpenShotApp", exc_info=1)
+        sys.exit()
     unittest.main()
+    app.exec_()
+
+
+if __name__ == '__main__':
+    main()