Use scope='session' for all fixtures

This means they will only be executed once which makes sense
since the database they create is immutable.

tests/test_api.py

@@ -9,9 +9,9 @@ from .fixtures import (
 import pytest
 import urllib
 
-pytest.fixture(scope='module')(app_client)
-pytest.fixture(scope='module')(app_client_shorter_time_limit)
-pytest.fixture(scope='module')(app_client_returend_rows_matches_page_size)
+pytest.fixture(scope='session')(app_client)
+pytest.fixture(scope='session')(app_client_shorter_time_limit)
+pytest.fixture(scope='session')(app_client_returend_rows_matches_page_size)
 
 
 def test_homepage(app_client):

tests/test_html.py

@@ -4,7 +4,7 @@ import pytest
 import re
 import urllib.parse
 
-pytest.fixture(scope='module')(app_client)
+pytest.fixture(scope='session')(app_client)
 
 
 def test_homepage(app_client):

tests/test_inspect.py

@@ -35,7 +35,7 @@ CREATE TABLE "office" (
 '''
 
 
-@pytest.fixture(scope='module')
+@pytest.fixture(scope='session')
 def ds_instance():
     with tempfile.TemporaryDirectory() as tmpdir:
         filepath = os.path.join(tmpdir, 'test_tables.db')