didn't actually add any new files connected to lyric.templatetags

src/apps/lyric/templatetags/lyric_extras.py

@@ -0,0 +1,26 @@
+from django import template
+
+register = template.Library()
+
+
+def truncate_email(email):
+    local, domain = email.split("@", 1)
+    domain_name, domain_tld = domain.rsplit(".", 1)
+
+    def truncate_segment(segment, n=2):
+        return segment[:n] + "…" + segment[-n:]
+
+    if len(local) >= 8:
+        local = truncate_segment(local)
+    if len(domain_name) >= 6:
+        domain_name = truncate_segment(domain_name, 1)
+    
+    return local + "@" + domain_name + "." + domain_tld
+
+@register.filter
+def display_name(user):
+    if user is None:
+        return ""
+    if user.username:
+        return user.username
+    return truncate_email(user.email)

src/apps/lyric/tests/unit/test_templatetags.py

@@ -0,0 +1,36 @@
+from django.test import SimpleTestCase
+from unittest.mock import Mock
+
+from apps.lyric.templatetags.lyric_extras import display_name, truncate_email
+
+
+class TruncateEmailTest(SimpleTestCase):
+    def test_truncates_neither_short_local_nor_short_domain(self):
+        self.assertEqual(truncate_email("abc@d.e"), "abc@d.e")
+
+    def test_truncates_only_long_local_not_short_domain(self):
+        self.assertEqual(truncate_email("sesquipedalian@abc.de"), "se…an@abc.de")
+
+    def test_truncates_not_short_local_only_long_domain(self):
+        self.assertEqual(truncate_email("abc@longexample.com"), "abc@l…e.com")
+
+    def test_truncates_both_long_local_and_long_domain(self):
+        self.assertEqual(truncate_email("onomatopoeia@earthmanrpg.com"), "on…ia@e…g.com")
+
+    def test_boundary_case_longish_segments_no_truncate(self):
+        self.assertEqual(truncate_email("abcdefg@gmail.com"), "abcdefg@gmail.com")
+
+    def test_boundary_case_exact_segments_do_truncate(self):
+        self.assertEqual(truncate_email("abcdefgh@icloud.com"), "ab…gh@i…d.com")
+
+class DisplayNameFilterTest(SimpleTestCase):
+    def test_returns_empty_string_for_none_user(self):
+        self.assertEqual(display_name(None), "")
+
+    def test_returns_truncated_email_when_no_username(self):
+        user = Mock(username="", email="sesquipedalian@abc.de")
+        self.assertEqual(display_name(user), "se…an@abc.de")
+
+    def test_returns_username_when_set(self):
+        user = Mock(username="earthman", email="sesquipedalian@abc.de")
+        self.assertEqual(display_name(user), "earthman")