fix: vCard parser drops folded continuation lines, corrupting emails (#1870)

tests/test_vcard_unfolding.py

@@ -0,0 +1,45 @@
+"""vCard parsing must unfold RFC 6350 folded lines.
+
+CardDAV servers fold logical lines longer than 75 octets onto continuation
+lines that begin with a space/tab. _parse_vcards split on raw newlines
+without unfolding, so a folded EMAIL/FN line lost its continuation (a long
+address like ...@exampledomain<fold>.com was stored as ...@exampledomain),
+silently corrupting the contact.
+"""
+from routes.contacts_routes import _parse_vcards
+
+
+def test_folded_email_is_reassembled():
+    vcard = (
+        "BEGIN:VCARD\r\n"
+        "VERSION:3.0\r\n"
+        "FN:John Doe\r\n"
+        "EMAIL;TYPE=INTERNET:john.doe.with.a.very.long.local.part@exampledomain\r\n"
+        " .com\r\n"
+        "END:VCARD\r\n"
+    )
+    contacts = _parse_vcards(vcard)
+    assert len(contacts) == 1
+    assert contacts[0]["emails"] == [
+        "john.doe.with.a.very.long.local.part@exampledomain.com"
+    ]
+
+
+def test_folded_display_name_is_reassembled():
+    vcard = (
+        "BEGIN:VCARD\n"
+        "FN:A Very Long Display Name That The Server\n"
+        "  Decided To Fold\n"
+        "EMAIL:x@y.com\n"
+        "END:VCARD\n"
+    )
+    c = _parse_vcards(vcard)[0]
+    assert c["name"] == "A Very Long Display Name That The Server Decided To Fold"
+
+
+def test_unfolded_vcard_still_parses():
+    vcard = "BEGIN:VCARD\nFN:Jane\nEMAIL:jane@z.com\nTEL:+15550001\nEND:VCARD\n"
+    c = _parse_vcards(vcard)[0]
+    assert c["name"] == "Jane"
+    assert c["emails"] == ["jane@z.com"]
+    assert c["phones"] == ["+15550001"]