add can_be_used_as_personal_email()

app/email_utils.py

@@ -288,3 +288,23 @@ def email_belongs_to_alias_domains(email: str) -> bool:
             return True
 
     return False
+
+
+def can_be_used_as_personal_email(email: str) -> bool:
+    """return True if an email can be used as a personal email. Currently the only condition is email domain is not
+    - one of ALIAS_DOMAINS
+    - one of custom domains
+    """
+    domain = get_email_domain_part(email)
+    if not domain:
+        return False
+
+    if domain in ALIAS_DOMAINS:
+        return False
+
+    from app.models import CustomDomain
+
+    if CustomDomain.get_by(domain=domain, verified=True):
+        return False
+
+    return True

tests/test_email_utils.py

@@ -4,7 +4,10 @@ from app.email_utils import (
     get_email_local_part,
     get_email_domain_part,
     email_belongs_to_alias_domains,
+    can_be_used_as_personal_email,
 )
+from app.extensions import db
+from app.models import User, CustomDomain
 
 
 def test_get_email_name():
@@ -36,3 +39,19 @@ def test_email_belongs_to_alias_domains():
 
     assert email_belongs_to_alias_domains("hey@d1.test")
     assert not email_belongs_to_alias_domains("hey@d3.test")
+
+
+def test_can_be_used_as_personal_email(flask_client):
+    # default alias domain
+    assert not can_be_used_as_personal_email("ab@sl.local")
+    assert not can_be_used_as_personal_email("hey@d1.test")
+
+    assert can_be_used_as_personal_email("hey@ab.cd")
+    # custom domain
+    user = User.create(
+        email="a@b.c", password="password", name="Test User", activated=True
+    )
+    db.session.commit()
+    CustomDomain.create(user_id=user.id, domain="ab.cd", verified=True)
+    db.session.commit()
+    assert not can_be_used_as_personal_email("hey@ab.cd")