diff --git a/poetry.lock b/poetry.lock
index 522229a50..97821005f 100644
--- a/poetry.lock
+++ b/poetry.lock
@@ -1278,6 +1278,7 @@ files = [
     {file = "lxml-5.2.1-cp36-cp36m-manylinux_2_12_i686.manylinux2010_i686.manylinux_2_17_i686.manylinux2014_i686.whl", hash = "sha256:c38d7b9a690b090de999835f0443d8aa93ce5f2064035dfc48f27f02b4afc3d0"},
     {file = "lxml-5.2.1-cp36-cp36m-manylinux_2_17_x86_64.manylinux2014_x86_64.whl", hash = "sha256:5670fb70a828663cc37552a2a85bf2ac38475572b0e9b91283dc09efb52c41d1"},
     {file = "lxml-5.2.1-cp36-cp36m-manylinux_2_28_x86_64.whl", hash = "sha256:958244ad566c3ffc385f47dddde4145088a0ab893504b54b52c041987a8c1863"},
+    {file = "lxml-5.2.1-cp36-cp36m-manylinux_2_5_x86_64.manylinux1_x86_64.whl", hash = "sha256:b6241d4eee5f89453307c2f2bfa03b50362052ca0af1efecf9fef9a41a22bb4f"},
     {file = "lxml-5.2.1-cp36-cp36m-musllinux_1_1_aarch64.whl", hash = "sha256:2a66bf12fbd4666dd023b6f51223aed3d9f3b40fef06ce404cb75bafd3d89536"},
     {file = "lxml-5.2.1-cp36-cp36m-musllinux_1_1_ppc64le.whl", hash = "sha256:9123716666e25b7b71c4e1789ec829ed18663152008b58544d95b008ed9e21e9"},
     {file = "lxml-5.2.1-cp36-cp36m-musllinux_1_1_s390x.whl", hash = "sha256:0c3f67e2aeda739d1cc0b1102c9a9129f7dc83901226cc24dd72ba275ced4218"},
@@ -1594,6 +1595,7 @@ files = [
     {file = "msgpack-1.0.8-cp39-cp39-musllinux_1_1_x86_64.whl", hash = "sha256:5fbb160554e319f7b22ecf530a80a3ff496d38e8e07ae763b9e82fadfe96f273"},
     {file = "msgpack-1.0.8-cp39-cp39-win32.whl", hash = "sha256:f9af38a89b6a5c04b7d18c492c8ccf2aee7048aff1ce8437c4683bb5a1df893d"},
     {file = "msgpack-1.0.8-cp39-cp39-win_amd64.whl", hash = "sha256:ed59dd52075f8fc91da6053b12e8c89e37aa043f8986efd89e61fae69dc1b011"},
+    {file = "msgpack-1.0.8-py3-none-any.whl", hash = "sha256:24f727df1e20b9876fa6e95f840a2a2651e34c0ad147676356f4bf5fbb0206ca"},
     {file = "msgpack-1.0.8.tar.gz", hash = "sha256:95c02b0e27e706e48d0e5426d1710ca78e0f0628d6e89d5b5a5b91a5f12274f3"},
 ]
 
diff --git a/tests/notifications_utils/clients/redis/test_redis_client.py b/tests/notifications_utils/clients/redis/test_redis_client.py
index 1f122206b..31ea2330a 100644
--- a/tests/notifications_utils/clients/redis/test_redis_client.py
+++ b/tests/notifications_utils/clients/redis/test_redis_client.py
@@ -8,17 +8,17 @@ from freezegun import freeze_time
 from notifications_utils.clients.redis.redis_client import RedisClient, prepare_value
 
 
-@pytest.fixture(scope="function")
+@pytest.fixture()
 def mocked_redis_pipeline():
     return Mock()
 
 
-@pytest.fixture
+@pytest.fixture()
 def delete_mock():
     return Mock(return_value=4)
 
 
-@pytest.fixture(scope="function")
+@pytest.fixture()
 def mocked_redis_client(app, mocked_redis_pipeline, delete_mock, mocker):
     app.config["REDIS_ENABLED"] = True
 
@@ -46,14 +46,16 @@ def mocked_redis_client(app, mocked_redis_pipeline, delete_mock, mocker):
     return redis_client
 
 
-@pytest.fixture
+@pytest.fixture()
 def failing_redis_client(mocked_redis_client, delete_mock):
-    mocked_redis_client.redis_store.get.side_effect = Exception("get failed")
-    mocked_redis_client.redis_store.set.side_effect = Exception("set failed")
-    mocked_redis_client.redis_store.incr.side_effect = Exception("incr failed")
-    mocked_redis_client.redis_store.pipeline.side_effect = Exception("pipeline failed")
-    mocked_redis_client.redis_store.delete.side_effect = Exception("delete failed")
-    delete_mock.side_effect = Exception("delete by pattern failed")
+    # nota bene: using KeyError because flake8 thinks Exception
+    # and BaseException are too broad
+    mocked_redis_client.redis_store.get.side_effect = KeyError("get failed")
+    mocked_redis_client.redis_store.set.side_effect = KeyError("set failed")
+    mocked_redis_client.redis_store.incr.side_effect = KeyError("incr failed")
+    mocked_redis_client.redis_store.pipeline.side_effect = KeyError("pipeline failed")
+    mocked_redis_client.redis_store.delete.side_effect = KeyError("delete failed")
+    delete_mock.side_effect = KeyError("delete by pattern failed")
     return mocked_redis_client
 
 
@@ -85,27 +87,27 @@ def test_should_raise_exception_if_raise_set_to_true(
     app,
     failing_redis_client,
 ):
-    with pytest.raises(Exception) as e:
+    with pytest.raises(KeyError) as e:
         failing_redis_client.get("test", raise_exception=True)
     assert str(e.value) == "get failed"
 
-    with pytest.raises(Exception) as e:
+    with pytest.raises(KeyError) as e:
         failing_redis_client.set("test", "test", raise_exception=True)
     assert str(e.value) == "set failed"
 
-    with pytest.raises(Exception) as e:
+    with pytest.raises(KeyError) as e:
         failing_redis_client.incr("test", raise_exception=True)
     assert str(e.value) == "incr failed"
 
-    with pytest.raises(Exception) as e:
+    with pytest.raises(KeyError) as e:
         failing_redis_client.exceeded_rate_limit("test", 100, 200, raise_exception=True)
     assert str(e.value) == "pipeline failed"
 
-    with pytest.raises(Exception) as e:
+    with pytest.raises(KeyError) as e:
         failing_redis_client.delete("test", raise_exception=True)
     assert str(e.value) == "delete failed"
 
-    with pytest.raises(Exception) as e:
+    with pytest.raises(KeyError) as e:
         failing_redis_client.delete_by_pattern("pattern", raise_exception=True)
     assert str(e.value) == "delete by pattern failed"
 
diff --git a/tests/notifications_utils/test_template_types.py b/tests/notifications_utils/test_template_types.py
index 1209d4dc9..0a329aca2 100644
--- a/tests/notifications_utils/test_template_types.py
+++ b/tests/notifications_utils/test_template_types.py
@@ -1044,7 +1044,7 @@ def test_letter_preview_renderer_without_mocks(jinja_template):
 @freeze_time("2012-12-12 12:12:12")
 @mock.patch("notifications_utils.template.LetterImageTemplate.jinja_template.render")
 @pytest.mark.parametrize(
-    "page_count, expected_oversized, expected_page_numbers",
+    ("page_count, expected_oversized, expected_page_numbers"),
     [
         (
             1,
@@ -1581,7 +1581,7 @@ def test_sms_fragment_count_accounts_for_unicode_and_welsh_characters(
     ),
 )
 @pytest.mark.parametrize(
-    "msg, expected_sms_fragment_count",
+    ("msg", "expected_sms_fragment_count"),
     [
         # all extended GSM characters
         (
@@ -1647,7 +1647,7 @@ def test_sms_fragment_count_accounts_for_non_latin_characters(
     ],
 )
 @pytest.mark.parametrize(
-    "content, values, prefix, expected_result",
+    ("content", "values", "prefix", "expected_result"),
     [
         ("", {}, None, True),
         ("", {}, "GDS", True),
@@ -1676,7 +1676,7 @@ def test_is_message_empty_sms_templates(
     ],
 )
 @pytest.mark.parametrize(
-    "content, values, expected_result",
+    ("content", "values", "expected_result"),
     [
         ("", {}, True),
         ("((placeholder))", {"placeholder": ""}, True),
@@ -1696,14 +1696,14 @@ def test_is_message_empty_broadcast_templates(
 
 
 @pytest.mark.parametrize(
-    "template_class, template_type",
+    ("template_class", "template_type"),
     (
         (HTMLEmailTemplate, "email"),
         (LetterPrintTemplate, "letter"),
     ),
 )
 @pytest.mark.parametrize(
-    "content, values, expected_result",
+    ("content", "values", "expected_result"),
     [
         ("", {}, True),
         ("((placeholder))", {"placeholder": ""}, True),
@@ -1742,7 +1742,7 @@ def test_is_message_empty_email_and_letter_templates(
     ),
 )
 @pytest.mark.parametrize(
-    "content, values",
+    ("content", "values"),
     [
         ("Some content", {}),
         ("((placeholder)) some content", {"placeholder": ""}),
@@ -1781,7 +1781,7 @@ def test_is_message_empty_email_and_letter_templates_tries_not_to_count_chars(
 
 
 @pytest.mark.parametrize(
-    "template_class, template_type, extra_args, expected_field_calls",
+    ("template_class", "template_type", "extra_args", "expected_field_calls"),
     [
         (
             PlainTextEmailTemplate,
@@ -2054,7 +2054,7 @@ def test_templates_handle_html_and_redacting(
 
 
 @pytest.mark.parametrize(
-    "template_class, template_type, extra_args, expected_remove_whitespace_calls",
+    ("template_class", "template_type", "extra_args", "expected_remove_whitespace_calls"),
     [
         (
             PlainTextEmailTemplate,
@@ -2176,7 +2176,7 @@ def test_templates_remove_whitespace_before_punctuation(
 
 
 @pytest.mark.parametrize(
-    "template_class, template_type, extra_args, expected_calls",
+    ("template_class", "template_type", "extra_args", "expected_calls"),
     [
         (
             PlainTextEmailTemplate,
@@ -2302,7 +2302,7 @@ def test_smart_quotes_removed_from_long_template_in_under_a_second():
 
 
 @pytest.mark.parametrize(
-    "template_instance, expected_placeholders",
+    ("template_instance", "expected_placeholders"),
     [
         (
             SMSMessageTemplate(
@@ -2465,7 +2465,7 @@ def test_email_preview_shows_reply_to_address(extra_args):
 
 
 @pytest.mark.parametrize(
-    "template_values, expected_content",
+    ("template_values", "expected_content"),
     [
         ({}, "<span class='placeholder-no-brackets'>email address</span>"),
         ({"email address": "test@example.com"}, "test@example.com"),
@@ -2483,7 +2483,7 @@ def test_email_preview_shows_recipient_address(
 
 
 @pytest.mark.parametrize(
-    "address, expected",
+    ("address", "expected"),
     [
         (
             {
@@ -2585,7 +2585,7 @@ def test_email_preview_shows_recipient_address(
         ),
     ],
 )
-@pytest.mark.parametrize("template_class", (LetterPreviewTemplate, LetterPrintTemplate))
+@pytest.mark.parametrize("template_class", [LetterPreviewTemplate, LetterPrintTemplate])
 def test_letter_address_format(template_class, address, expected):
     template = BeautifulSoup(
         str(
@@ -2601,7 +2601,7 @@ def test_letter_address_format(template_class, address, expected):
 
 @freeze_time("2001-01-01 12:00:00.000000")
 @pytest.mark.parametrize(
-    "markdown, expected",
+    ("markdown", "expected"),
     [
         (
             (
@@ -2691,11 +2691,11 @@ def test_message_is_not_too_long_ignoring_prefix(template_class):
 
 
 @pytest.mark.parametrize(
-    "extra_characters, expected_too_long",
-    (
+    ("extra_characters", "expected_too_long"),
+    [
         ("cc", True),  # content length is 919 characters (more than limit of 918)
         ("c", False),  # content length is 918 characters (not more than limit of 918)
-    ),
+    ],
 )
 @pytest.mark.parametrize(
     "template_class",
@@ -2716,7 +2716,7 @@ def test_broadcast_message_too_long(
 
 
 @pytest.mark.parametrize(
-    "template_class, template_type, kwargs",
+    ("template_class", "template_type", "kwargs"),
     [
         (EmailPreviewTemplate, "email", {}),
         (HTMLEmailTemplate, "email", {}),
@@ -2736,7 +2736,7 @@ def test_message_too_long_limit_bigger_or_nonexistent_for_non_sms_templates(
 
 
 @pytest.mark.parametrize(
-    "template_class, template_type, kwargs",
+    ("template_class", "template_type", "kwargs"),
     [
         (EmailPreviewTemplate, "email", {}),
         (HTMLEmailTemplate, "email", {}),
@@ -2755,7 +2755,7 @@ def test_content_size_in_bytes_for_email_messages(
 
 
 @pytest.mark.parametrize(
-    "template_class, template_type, kwargs",
+    ("template_class", "template_type", "kwargs"),
     [
         (EmailPreviewTemplate, "email", {}),
         (HTMLEmailTemplate, "email", {}),
@@ -2774,7 +2774,7 @@ def test_message_too_long_for_a_too_big_email_message(
 
 
 @pytest.mark.parametrize(
-    "template_class, template_type, kwargs",
+    ("template_class", "template_type", "kwargs"),
     [
         (EmailPreviewTemplate, "email", {}),
         (HTMLEmailTemplate, "email", {}),
@@ -2792,7 +2792,7 @@ def test_message_too_long_for_an_email_message_within_limits(
 
 
 @pytest.mark.parametrize(
-    ("content," "expected_preview_markup,"),
+    ("content", "expected_preview_markup"),
     [
         (
             "a\n\n\nb",
@@ -2847,7 +2847,7 @@ def test_multiple_newlines_in_letters(
     ],
 )
 @pytest.mark.parametrize(
-    "template_class, template_type, extra_args",
+    ("template_class", "template_type", "extra_args"),
     [
         (PlainTextEmailTemplate, "email", {}),
         (HTMLEmailTemplate, "email", {}),
@@ -2886,7 +2886,7 @@ def test_whitespace_in_subject_placeholders(template_class):
 
 
 @pytest.mark.parametrize(
-    "template_class, expected_output",
+    ("template_class", "expected_output"),
     [
         (
             PlainTextEmailTemplate,
@@ -3041,8 +3041,8 @@ def test_plain_text_email_whitespace():
 
 
 @pytest.mark.parametrize(
-    "renderer, template_type, expected_content",
-    (
+    ("renderer", "template_type", "expected_content"),
+    [
         (
             PlainTextEmailTemplate,
             "email",
@@ -3071,7 +3071,7 @@ def test_plain_text_email_whitespace():
             "letter",
             ("<h2>Heading link: <strong>example.com</strong></h2>"),
         ),
-    ),
+    ],
 )
 def test_heading_only_template_renders(renderer, template_type, expected_content):
     assert expected_content in str(
@@ -3093,7 +3093,7 @@ def test_heading_only_template_renders(renderer, template_type, expected_content
     ],
 )
 @pytest.mark.parametrize(
-    "filename, expected_html_class",
+    ("filename", "expected_html_class"),
     [
         ("example.png", 'class="png"'),
         ("example.svg", 'class="svg"'),
@@ -3127,7 +3127,7 @@ def test_image_not_present_if_no_logo(template_class):
 
 @pytest.mark.parametrize(
     "content",
-    (
+    [
         (
             "The     quick brown fox.\n"
             "\n\n\n\n"
@@ -3140,11 +3140,11 @@ def test_image_not_present_if_no_logo(template_class):
             "          Jumps over the lazy dog   .  \n"
             "Single linebreak above. \n  \n \n"
         ),
-    ),
+    ],
 )
 @pytest.mark.parametrize(
-    "template_class, expected",
-    (
+    ("template_class", "expected"),
+    [
         (
             SMSBodyPreviewTemplate,
             (
@@ -3192,7 +3192,7 @@ def test_image_not_present_if_no_logo(template_class):
                 "</div>"
             ),
         ),
-    ),
+    ],
 )
 def test_text_messages_collapse_consecutive_whitespace(
     template_class,
@@ -3252,14 +3252,14 @@ def test_broadcast_message_from_event():
 
 @pytest.mark.parametrize(
     "template_class",
-    (
+    [
         BroadcastMessageTemplate,
         BroadcastPreviewTemplate,
-    ),
+    ],
 )
 @pytest.mark.parametrize(
-    "content, expected_non_gsm, expected_max, expected_too_long",
-    (
+    ("content", "expected_non_gsm", "expected_max", "expected_too_long"),
+    [
         (
             "a" * 1395,
             set(),
@@ -3304,7 +3304,7 @@ def test_broadcast_message_from_event():
             615,
             False,
         ),
-    ),
+    ],
 )
 def test_broadcast_message_content_count(
     content, expected_non_gsm, expected_max, expected_too_long, template_class
@@ -3322,10 +3322,12 @@ def test_broadcast_message_content_count(
 
 @pytest.mark.parametrize(
     "template_class",
-    (
-        BroadcastMessageTemplate,
-        BroadcastPreviewTemplate,
-    ),
+    [
+        (
+            BroadcastMessageTemplate,
+            BroadcastPreviewTemplate,
+        ),
+    ],
 )
 @pytest.mark.parametrize("content", ("^{}\\[~]|€"))
 def test_broadcast_message_double_counts_extended_gsm(
@@ -3344,10 +3346,12 @@ def test_broadcast_message_double_counts_extended_gsm(
 
 @pytest.mark.parametrize(
     "template_class",
-    (
-        BroadcastMessageTemplate,
-        BroadcastPreviewTemplate,
-    ),
+    [
+        (
+            BroadcastMessageTemplate,
+            BroadcastPreviewTemplate,
+        ),
+    ],
 )
 @pytest.mark.parametrize(
     "content", ("ÁÍÓÚẂÝ" "ËÏẄŸ" "ÂÊÎÔÛŴŶ" "ÀÈÌÒẀÙỲ" "áíóúẃý" "ëïẅÿ" "âêîôûŵŷ" "ẁỳ")
@@ -3368,10 +3372,12 @@ def test_broadcast_message_single_counts_diacritics_in_extended_gsm(
 
 @pytest.mark.parametrize(
     "template_class",
-    (
-        BroadcastMessageTemplate,
-        BroadcastPreviewTemplate,
-    ),
+    [
+        (
+            BroadcastMessageTemplate,
+            BroadcastPreviewTemplate,
+        ),
+    ],
 )
 @pytest.mark.parametrize("content", ("ÄÖÜ" "É" "äöü" "é" "àèìòù"))
 def test_broadcast_message_single_counts_diacritics_in_gsm(