🎨 [#4650] Clean up email tests

Simplified tests by removing indirection and only set up the test data
that is actually required by the test. This also uses some more
ergonomic factory utilities rather than hand-wiring everything.

Now new tests should have better examples to follow.

src/openforms/registrations/contrib/email/tests/test_backend.py

@@ -19,11 +19,6 @@
     EmailContentTypeChoices,
     EmailEventChoices,
 )
-from openforms.forms.tests.factories import (
-    FormDefinitionFactory,
-    FormFactory,
-    FormStepFactory,
-)
 from openforms.payments.constants import PaymentStatus
 from openforms.payments.tests.factories import SubmissionPaymentFactory
 from openforms.submissions.attachments import attach_uploads_to_submission_step
@@ -32,7 +27,6 @@
 from openforms.submissions.tests.factories import (
     SubmissionFactory,
     SubmissionFileAttachmentFactory,
-    SubmissionReportFactory,
     SubmissionStepFactory,
     SubmissionValueVariableFactory,
     TemporaryFileUploadFactory,
@@ -83,35 +77,6 @@ def _get_sent_email(index: int = 0) -> tuple[mail.EmailMultiAlternatives, str, s
     LANGUAGE_CODE="nl",
 )
 class EmailBackendTests(HTMLAssertMixin, TestCase):
-    @classmethod
-    def setUpTestData(cls):
-        super().setUpTestData()
-
-        fd = FormDefinitionFactory.create(
-            configuration={
-                "components": [
-                    {
-                        "key": "someField",
-                        "label": "Some Field",
-                        "type": "textfield",
-                    },
-                    {
-                        "key": "someList",
-                        "label": "Some list",
-                        "type": "textfield",
-                        "multiple": True,
-                    },
-                ],
-            }
-        )
-        form = FormFactory.create(
-            name="MyName",
-            internal_name="MyInternalName",
-            registration_backend="email",
-        )
-        cls.fs = FormStepFactory.create(form=form, form_definition=fd)
-        cls.form = form
-        cls.fd = fd
 
     def setUp(self):
         super().setUp()
@@ -533,7 +498,9 @@ def test_register_and_update_paid_product(self):
         self.assertIn("<table", message_html)
         self.assertNotIn("<table", message_text)
 
-        detail_line = f"Betaling ontvangen voor {self.form.name} (ingezonden op 12:00:00 01-01-2021)"
+        detail_line = (
+            f"Betaling ontvangen voor MyName (ingezonden op 12:00:00 01-01-2021)"
+        )
         self.assertIn(detail_line, message_html)
         self.assertIn(detail_line, message_text)
 
@@ -665,16 +632,29 @@ def test_submission_with_email_backend_export_csv_xlsx(self):
             "attachment_formats": [AttachmentFormat.csv, AttachmentFormat.xlsx],
             "attach_files_to_email": None,
         }
-
-        data = {"someField": "value0", "someList": ["value1", "value2"]}
-
-        submission = SubmissionFactory.create(form=self.form)
-        submission_step = SubmissionStepFactory.create(
-            submission=submission, form_step=self.fs, data=data
+        submission = SubmissionFactory.from_components(
+            [
+                {
+                    "key": "someField",
+                    "label": "Some Field",
+                    "type": "textfield",
+                },
+                {
+                    "key": "someList",
+                    "label": "Some list",
+                    "type": "textfield",
+                    "multiple": True,
+                },
+            ],
+            submitted_data={"someField": "value0", "someList": ["value1", "value2"]},
+            completed=True,
+            completed_on=timezone.make_aware(datetime(2021, 1, 1, 12, 0, 0)),
+            form__name="MyName",
+            form__internal_name="MyInternalName",
+        )
+        submission_step = (
+            submission.submissionstep_set.get()  # pyright: ignore[reportAttributeAccessIssue]
         )
-        submission.completed_on = timezone.make_aware(datetime(2021, 1, 1, 12, 0, 0))
-        submission.save()
-
         SubmissionFileAttachmentFactory.create(
             submission_step=submission_step,
             file_name="my-foo.bin",
@@ -750,18 +730,26 @@ def test_submission_with_email_backend_export_pdf(self):
             "attachment_formats": [AttachmentFormat.pdf],
             "attach_files_to_email": None,
         }
-
-        data = {"foo": "bar", "some_list": ["value1", "value2"]}
-
-        submission = SubmissionFactory.create(form=self.form)
-        submission_step = SubmissionStepFactory.create(
-            submission=submission, form_step=self.fs, data=data
+        submission = SubmissionFactory.from_components(
+            [
+                {
+                    "key": "someField",
+                    "label": "Some Field",
+                    "type": "textfield",
+                },
+                {
+                    "key": "someList",
+                    "label": "Some list",
+                    "type": "textfield",
+                    "multiple": True,
+                },
+            ],
+            submitted_data={"someField": "value0", "someList": ["value1", "value2"]},
+            completed=True,
+        )
+        submission_step = (
+            submission.submissionstep_set.get()  # pyright: ignore[reportAttributeAccessIssue]
         )
-        submission.completed_on = timezone.make_aware(datetime(2021, 1, 1, 12, 0, 0))
-        submission.save()
-
-        report = SubmissionReportFactory.create(submission=submission)
-
         SubmissionFileAttachmentFactory.create(
             submission_step=submission_step,
             file_name="my-foo.bin",
@@ -785,9 +773,8 @@ def test_submission_with_email_backend_export_pdf(self):
         self.assertEqual(len(message.attachments), 1)
 
         pdf_export = message.attachments[0]
-
-        self.assertEqual(pdf_export[0], f"{report.title}.pdf")
-        self.assertEqual(pdf_export[1], report.content.read())
+        self.assertEqual(pdf_export[0], f"{submission.report.title}.pdf")
+        self.assertEqual(pdf_export[1], submission.report.content.read())
         self.assertEqual(pdf_export[2], "application/pdf")
 
     def test_regression_nested_components_columns(self):