diff --git a/tests/test_edit.py b/tests/test_edit.py
new file mode 100644
index 0000000..2ecb5c2
--- /dev/null
+++ b/tests/test_edit.py
@@ -0,0 +1,142 @@
+import pytest
+import aqt.operations.note
+from plugin.edit import Edit, DecentPreviewer, history
+
+
+def test_edit_dialog_opens(setup):
+    Edit.open_dialog_and_show_note_with_id(setup.note1_id)
+
+
+def test_edit_dialog_opens_only_once(setup):
+    dialog1 = Edit.open_dialog_and_show_note_with_id(setup.note1_id)
+    dialog2 = Edit.open_dialog_and_show_note_with_id(setup.note1_id)
+    assert dialog1 is dialog2
+
+
+def test_edit_dialog_fails_to_open_with_invalid_note(setup):
+    with pytest.raises(Exception):
+        Edit.open_dialog_and_show_note_with_id(123)
+
+
+def test_browser_dialog_opens(setup):
+    dialog = Edit.open_dialog_and_show_note_with_id(setup.note1_id)
+    dialog.show_browser()
+
+
+class TestPreviewDialog:
+    def test_opens(self, setup):
+        edit_dialog = Edit.open_dialog_and_show_note_with_id(setup.note1_id)
+        edit_dialog.show_preview()
+
+    @pytest.fixture
+    def dialog(self, setup):
+        edit_dialog = Edit.open_dialog_and_show_note_with_id(setup.note1_id)
+        preview_dialog: DecentPreviewer = edit_dialog.show_preview()
+
+        def press_next_button(times=0):
+            for _ in range(times):
+                preview_dialog._last_render = 0         # render without delay
+                preview_dialog._on_next()
+
+        preview_dialog.press_next_button = press_next_button
+
+        yield preview_dialog
+
+    @pytest.mark.parametrize(
+        "next_button_presses, current_card, "
+        "showing_question_only, previous_enabled, next_enabled",
+        [
+            pytest.param(0, 0, True, False, True,
+                    id="next button pressed 0 times; first card, question"),
+            pytest.param(1, 0, False, True, True,
+                    id="next button pressed 1 time;  first card, answer"),
+            pytest.param(2, 1, True,  True, True,
+                    id="next button pressed 2 times; second card, question"),
+            pytest.param(3, 1, False, True, False,
+                    id="next button pressed 3 times; second card, answer"),
+            pytest.param(4, 1, False, True, False,
+                    id="next button pressed 4 times; second card still, answer"),
+        ]
+    )
+    def test_navigation(self, dialog, next_button_presses, current_card,
+            showing_question_only, previous_enabled, next_enabled):
+        dialog.press_next_button(times=next_button_presses)
+        assert dialog.adapter.current == current_card
+        assert dialog.showing_question_and_can_show_answer() is showing_question_only
+        assert dialog._should_enable_prev() is previous_enabled
+        assert dialog._should_enable_next() is next_enabled
+
+
+class TestHistory:
+    @pytest.fixture(autouse=True)
+    def cleanup(self):
+        history.note_ids = []
+
+    def test_single_note(self, setup):
+        assert history.note_ids == []
+        Edit.open_dialog_and_show_note_with_id(setup.note1_id)
+        assert history.note_ids == [setup.note1_id]
+
+    def test_two_notes(self, setup):
+        Edit.open_dialog_and_show_note_with_id(setup.note1_id)
+        Edit.open_dialog_and_show_note_with_id(setup.note2_id)
+        assert history.note_ids == [setup.note1_id, setup.note2_id]
+
+    def test_old_note_reopened(self, setup):
+        Edit.open_dialog_and_show_note_with_id(setup.note1_id)
+        Edit.open_dialog_and_show_note_with_id(setup.note2_id)
+        Edit.open_dialog_and_show_note_with_id(setup.note1_id)
+        assert history.note_ids == [setup.note2_id, setup.note1_id]
+
+    def test_navigation(self, setup):
+        dialog = Edit.open_dialog_and_show_note_with_id(setup.note1_id)
+        Edit.open_dialog_and_show_note_with_id(setup.note2_id)
+
+        dialog.show_previous()
+        assert dialog.note.id == setup.note1_id
+
+        dialog.show_previous()
+        assert dialog.note.id == setup.note1_id
+
+        dialog.show_next()
+        assert dialog.note.id == setup.note2_id
+
+        dialog.show_next()
+        assert dialog.note.id == setup.note2_id
+
+
+class TestNoteDeletionElsewhere:
+    @pytest.fixture
+    def delete_note(self, run_background_tasks_on_main_thread):
+        """
+        Yields a function that accepts a single note id and deletes the note,
+        running the required hooks in sync
+        """
+        return (
+            lambda note_id: aqt.operations.note
+                .remove_notes(parent=None, note_ids=[note_id])  # noqa
+                .run_in_background()
+        )
+
+    @staticmethod
+    def edit_dialog_is_open():
+        return aqt.dialogs._dialogs[Edit.dialog_registry_tag][1] is not None  # noqa
+
+    @pytest.fixture
+    def dialog(self, setup):
+        Edit.open_dialog_and_show_note_with_id(setup.note1_id)
+        yield Edit.open_dialog_and_show_note_with_id(setup.note2_id)
+
+    def test_one_of_the_history_notes_is_deleted_and_dialog_stays(self,
+            setup, dialog, delete_note):
+        assert dialog.note.id == setup.note2_id
+
+        delete_note(setup.note2_id)
+        assert self.edit_dialog_is_open()
+        assert dialog.note.id == setup.note1_id
+
+    def test_all_of_the_history_notes_are_deleted_and_dialog_closes(self,
+            setup, dialog, delete_note):
+        delete_note(setup.note1_id)
+        delete_note(setup.note2_id)
+        assert not self.edit_dialog_is_open()