I have a sneaking suspicion that the work Akshay and Khushboo have been doing might have broken this :-(
Yup, earlier we were able to create a schema if not exists while running alter test cases. As this capability is remove alter test case for extension was failing.
I have fixed the test case, PFA updated patch.
Create Extension with all options..............OK ... 2019-07-09 12:22:55,268: ERROR flask.app: Failed to execute query (execute_dict) for the server #5- DB:test_db_d08e5 (Query-id: 1400245): Error Message:ERROR: schema "test_extension_schema" does not exist
Alter Extension version..............FAIL Traceback (most recent call last): File "/Users/dpage/git/pgadmin4/web/regression/re_sql/tests/test_resql.py", line 230, in execute_test_case self.assertEquals(response.status_code, 200) File "/opt/local/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/unittest/case.py", line 1338, in deprecated_func return original_func(*args, **kwargs) File "/opt/local/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/unittest/case.py", line 839, in assertEqual assertion_func(first, second, msg=msg) File "/opt/local/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/unittest/case.py", line 832, in _baseAssertEqual raise self.failureException(msg) AssertionError: 500 != 200