Function.upper() failed to operate non-ASCII characters

CBL VERSION:  → 2.6.0-154

CBS VERSION: 6.0.1-2037

SGW VERSION: 2.6.0-127

Steps to Reproduce: 

1. install cbs server and enable travel-sample bucket
2. install sgw and connect to cbs server
3. have an Android app reference CBLite 2.6 libraries, (in my case, use TestServer Android app), and run this statement:
   let searchQuery = Query
   .select(SelectResult.expression(Expression.meta().id),
   SelectResult.expression(Expression.property("email")),
   SelectResult.expression(Function.upper(Expression.property("name"))))
   .from(DataSource.database(db))
   .where(Expression.property("email").and(Function.contains(Expression.property("email"),
   substring: "maisondeverlaine@gmail.com")))

Actual Result:

{'$1': 'LA MAISON DE VERLAINE *à* METZ', 'email': 'maisondeverlaine@gmail.com', 'id': 'landmark_17957'}

Expected Result:

{'$1': 'LA MAISON DE VERLAINE *À* METZ', 'email': 'maisondeverlaine@gmail.com', 'id': 'landmark_17957'}

 

non-ascii character à didn't not converted to À, This behavior is only seen on Android, NOT on iOS or .net platforms

Logs : attached

Jenkins job Failure  link:

*http://uberjenkins.sc.couchbase.com:8080/job/Android-Listener-TestServer-Query-tests/336/*

Pytest command:

pytest -s -rsx --timeout=1800 --liteserv-version=2.6.0-154 --liteserv-host=192.168.33.126 --liteserv-port=8080 --xattrs --sync-gateway-version=2.6.0-127 --mode=cc --server-version=6.0.1-2037 --liteserv-platform=android --create-db-per-suite=cbl-test --enable-sample-bucket=travel-sample /Users/eunicehuang/dev/mobile-testkit/testsuites/CBLTester/CBL_Functional_tests/SuiteSetup_FunctionalTests/  -k test_query_substring