diff --git a/src/vorta/views/source_tab.py b/src/vorta/views/source_tab.py
index 13a48f5e..68d9c336 100644
--- a/src/vorta/views/source_tab.py
+++ b/src/vorta/views/source_tab.py
@@ -379,4 +379,5 @@ class SourceTab(SourceBase, SourceUI, BackupProfileMixin):
         if len(invalidSources) != 0:  # Check if any invalid paths
             msg = QMessageBox()
             msg.setText(self.tr("Some of your sources are invalid:") + invalidSources)
+            self._msg = msg  # for testing
             msg.exec()
diff --git a/tests/unit/test_source.py b/tests/unit/test_source.py
index a4209576..10fa0ed4 100644
--- a/tests/unit/test_source.py
+++ b/tests/unit/test_source.py
@@ -1,22 +1,102 @@
 import pytest
 import vorta.views
+from PyQt6 import QtCore
+from PyQt6.QtWidgets import QMessageBox
 
 
-def test_add_folder(qapp, qtbot, mocker, monkeypatch, choose_file_dialog):
+@pytest.fixture()
+def source_env(qapp, qtbot, monkeypatch, choose_file_dialog):
+    """
+    Handles common setup and teardown for unit tests involving the source tab.
+    """
     monkeypatch.setattr(vorta.views.source_tab, "choose_file_dialog", choose_file_dialog)
     main = qapp.main_window
     main.tabWidget.setCurrentIndex(1)
     tab = main.sourceTab
+    qtbot.waitUntil(lambda: tab.sourceFilesWidget.rowCount() == 1, timeout=2000)
 
-    tab.source_add(want_folder=True)
-    qtbot.waitUntil(lambda: tab.sourceFilesWidget.rowCount() == 2, **pytest._wait_defaults)
-
-    # Test paste button with mocked clipboard
-    mock_clipboard = mocker.Mock()
-    mock_clipboard.text.return_value = __file__
-    mocker.patch.object(vorta.views.source_tab.QApplication, 'clipboard', return_value=mock_clipboard)
-    tab.paste_text()
-    qtbot.waitUntil(lambda: tab.sourceFilesWidget.rowCount() == 3, **pytest._wait_defaults)
+    yield main, tab
 
     # Wait for directory sizing to finish
-    qtbot.waitUntil(lambda: len(qapp.main_window.sourceTab.updateThreads) == 0, **pytest._wait_defaults)
+    qtbot.waitUntil(lambda: len(qapp.main_window.sourceTab.updateThreads) == 0, timeout=2000)
+
+
+def test_source_add_remove(qapp, qtbot, monkeypatch, mocker, source_env):
+    """
+    Tests adding and removing source to ensure expected behavior.
+    """
+    main, tab = source_env
+    mocker.patch.object(QMessageBox, "exec")  # prevent QMessageBox from stopping test
+
+    # test adding a folder with os access
+    mocker.patch('os.access', return_value=True)
+    tab.source_add(want_folder=True)
+    qtbot.waitUntil(lambda: tab.sourceFilesWidget.rowCount() == 2, **pytest._wait_defaults)
+    assert tab.sourceFilesWidget.rowCount() == 2
+
+    # test adding a folder without os access
+    mocker.patch('os.access', return_value=False)
+    tab.source_add(want_folder=True)
+    assert tab.sourceFilesWidget.rowCount() == 2
+
+    # test removing a folder
+    tab.sourceFilesWidget.selectRow(1)
+    qtbot.mouseClick(tab.removeButton, QtCore.Qt.MouseButton.LeftButton)
+    qtbot.waitUntil(lambda: tab.sourceFilesWidget.rowCount() == 1, **pytest._wait_defaults)
+    assert tab.sourceFilesWidget.rowCount() == 1
+
+
+@pytest.mark.parametrize(
+    "path, valid",
+    [
+        (__file__, True),  # valid path
+        ("test", False),  # invalid path
+        (f"file://{__file__}", True),  # valid - normal path with prefix that will be stripped
+        (f"file://{__file__}\n{__file__}", True),  # valid - two files separated by new line
+        (f"file://{__file__}{__file__}", False),  # invalid - no new line separating file names
+    ],
+)
+def test_valid_and_invalid_source_paths(qapp, qtbot, mocker, source_env, path, valid):
+    """
+    Valid paths will be added as a source.
+    Invalid paths will trigger an alert and not be added as a source.
+    """
+    main, tab = source_env
+    mock_clipboard = mocker.Mock()
+    mock_clipboard.text.return_value = path
+
+    mocker.patch.object(vorta.views.source_tab.QApplication, 'clipboard', return_value=mock_clipboard)
+    mocker.patch.object(QMessageBox, "exec")  # prevent QMessageBox from stopping test
+    tab.paste_text()
+
+    if valid:
+        assert not hasattr(tab, '_msg')
+        qtbot.waitUntil(lambda: tab.sourceFilesWidget.rowCount() == 2, **pytest._wait_defaults)
+        assert tab.sourceFilesWidget.rowCount() == 2
+    else:
+        qtbot.waitUntil(lambda: hasattr(tab, "_msg"), **pytest._wait_defaults)
+        assert tab._msg.text().startswith("Some of your sources are invalid")
+        assert tab.sourceFilesWidget.rowCount() == 1
+
+
+def test_sources_update(qapp, qtbot, mocker, source_env):
+    """
+    Tests the source update button in the source tab
+    """
+    main, tab = source_env
+    update_path_info_spy = mocker.spy(tab, "update_path_info")
+
+    # test that `update_path_info()` has been called for each source path
+    qtbot.mouseClick(tab.updateButton, QtCore.Qt.MouseButton.LeftButton)
+    assert tab.sourceFilesWidget.rowCount() == 1
+    assert update_path_info_spy.call_count == 1
+
+    # add a new source and reset mock
+    tab.source_add(want_folder=True)
+    qtbot.waitUntil(lambda: tab.sourceFilesWidget.rowCount() == 2, **pytest._wait_defaults)
+    update_path_info_spy.reset_mock()
+
+    # retest that `update_path_info()` has been called for each source path
+    qtbot.mouseClick(tab.updateButton, QtCore.Qt.MouseButton.LeftButton)
+    assert tab.sourceFilesWidget.rowCount() == 2
+    assert update_path_info_spy.call_count == 2