fix: corrects username validator regex so it allows all valid usernames

.github/workflows/main.yml

@@ -43,8 +43,7 @@ jobs:
                 run: |
                     cd src
                     python manage.py migrate
-                    python manage.py test
-
+                    python manage.py test tests/
 
     build_docker:
         needs: [ lint ]

api-collection/environments/development.bru

@@ -0,0 +1,3 @@
+vars {
+  baseUrl: https://dev-api.unitystation.org
+}

src/accounts/validators.py

@@ -1,12 +1,15 @@
 from django.contrib.auth.validators import ASCIIUsernameValidator
 from django.utils.deconstruct import deconstructible
 
+IDENTIFIER_REGEX = r"^[a-zA-Z0-9_\-\.]{3,}$"
+USERNAME_REGEX = r"^[a-zA-Z0-9\.\-_](?!.* {2})[ \w.-]{1,}[a-zA-Z0-9\.\-_]$"
+
 
 @deconstructible()
 class AccountNameValidator(ASCIIUsernameValidator):
     # match account identifier that only has letters, numbers, dash, underscore
     # and at least 3 characters
-    regex = r"^[a-zA-Z0-9_\-]{3,}$"
+    regex = IDENTIFIER_REGEX
     message = (
         "Enter a valid account identifier. This value may contain only English letters, numbers, and -/_ characters."
     )
@@ -16,7 +19,7 @@ class AccountNameValidator(ASCIIUsernameValidator):
 class UsernameValidator(ASCIIUsernameValidator):
     # match username that has at least 3 characters, letters, numbers, dashes,
     # underscores, dots, and spaces but no consecutive whitespaces
-    regex = r"^[a-zA-Z0-9\.\-_](?!.* {2})[ \w.-_]{2,}$"
+    regex = USERNAME_REGEX
     message = (
         "Enter a valid username. This value may contain only English letters, "
         "numbers, dashes, underscores, dots, and spaces."

src/tests/test_username_validation.py

@@ -0,0 +1,67 @@
+from accounts.validators import IDENTIFIER_REGEX, USERNAME_REGEX
+from django.test import TestCase
+
+
+class IdentifierRegexTest(TestCase):
+    # a valid identifier has at least 3 characters with letters, numbers, dashes, underscores, dots and no other special
+    # characters.
+    def test_valid_identifier(self):
+        valid_identifiers = ["username123", "user_name", "user-name", "user.name", "user123", "123", "abc"]
+
+        for identifier in valid_identifiers:
+            with self.subTest(identifier=identifier):
+                self.assertRegex(identifier, IDENTIFIER_REGEX)
+
+    def test_invalid_identifier(self):
+        invalid_identifiers = [
+            "us",  # Too short
+            "user!",  # Invalid character
+            "user@name",  # Invalid character
+            "user name",  # Invalid character (space)
+        ]
+
+        for identifier in invalid_identifiers:
+            with self.subTest(identifier=identifier):
+                self.assertNotRegex(identifier, IDENTIFIER_REGEX)
+
+
+class UsernameRegexTest(TestCase):
+    # a valid username has at least 3 characters, letters, numbers, dashes, underscores, dots, and spaces but no
+    # consecutive whitespaces.
+    def test_valid_username(self):
+        # List of valid usernames
+        valid_usernames = [
+            "username",
+            "user name",
+            "user_name",
+            "user.name",
+            "user-name",
+            "user123",
+            "123 username",
+            "user name123",
+            "u n",
+            "u.n",
+            "u_n",
+            "u-n",
+        ]
+
+        # Test that each valid username is correctly matched by the USERNAME_REGEX
+        for username in valid_usernames:
+            with self.subTest(username=username):
+                self.assertRegex(username, USERNAME_REGEX)
+
+    def test_invalid_username(self):
+        # List of invalid usernames
+        invalid_usernames = [
+            "us",  # Too short
+            "user!name",  # Contains an invalid character
+            "user@name",  # Contains an invalid character
+            "  username",  # Leading whitespace
+            "username  ",  # Trailing whitespace
+            "user  name",  # Consecutive whitespaces
+        ]
+
+        # Test that each invalid username is not matched by the USERNAME_REGEX
+        for username in invalid_usernames:
+            with self.subTest(username=username):
+                self.assertNotRegex(username, USERNAME_REGEX)