Added/Updated tests\bugs\gh_7604_test.py: Checked on 4.0.3.2947, 5.0.0.1063 -- all fine.

tests/bugs/gh_7604_test.py

@@ -0,0 +1,45 @@
+#coding:utf-8
+
+"""
+ID:          issue-7604
+ISSUE:       https://github.com/FirebirdSQL/firebird/issues/7604
+TITLE:       PSQL functions do not convert the output BLOB to the connection character set
+NOTES:
+    [03.06.2023] pzotov
+    Confirmed problem on 4.0.3.2943, 5.0.0.1060.
+    Checked on 4.0.3.2947, 5.0.0.1063 -- all fine.
+"""
+import locale
+import pytest
+from firebird.qa import *
+
+db = db_factory(charset = 'utf8')
+
+act = python_act('db', substitutions=[('^((?!sqltype:).)*$',''),('[ \t]+',' '),('.*alias:.*','')])
+
+@pytest.mark.version('>=4.0.3')
+def test_1(act: Action):
+
+    test_sql = """
+        set term ^;
+        create or alter function sp_test_func returns blob sub_type text character set utf8 as
+            declare runtotal blob sub_type text;
+        begin
+            runtotal = 'мама мыла раму';
+            return runtotal;
+        end
+        ^
+        set term ;^
+        commit;
+        set list on;
+        set sqlda_display on;
+        select sp_test_func() as runtotal from rdb$database rows 0;
+    """
+
+    expected_stdout = """
+        01: sqltype: 520 BLOB Nullable scale: 0 subtype: 1 len: 8 charset: 52 WIN1251
+    """
+
+    act.expected_stdout = expected_stdout
+    act.isql(switches=['-q'], charset = 'win1251', input = test_sql, combine_output = True, io_enc = locale.getpreferredencoding())
+    assert act.clean_stdout == act.clean_expected_stdout