Added/Updated tests\bugs\gh_7176_test.py: Checked on 5.0.0.959, 4.0.3.2903, 3.0.11.33664 -- all OK.

tests/bugs/gh_7176_test.py

@@ -0,0 +1,42 @@
+#coding:utf-8
+
+"""
+ID:          issue-7176
+ISSUE:       https://github.com/FirebirdSQL/firebird/issues/7176
+TITLE:       Incorrect error "Invalid token. Malformed string." with union + blob + non utf8 varchar
+NOTES:
+    [27.02.2023] pzotov
+    Confirmed bug on 5.0.0.488 (date of build: 25-apr-2022).
+    Checked on 5.0.0.959, 4.0.3.2903, 3.0.11.33664 -- all OK.
+"""
+
+import pytest
+from firebird.qa import *
+
+db = db_factory()
+
+act = python_act('db', substitutions = [('BLOB_ID\\s+\\d+:\\d+', 'BLOB_ID')])
+
+expected_stdout = """
+    BLOB_ID                         <null>
+    BLOB_ID                         0:2
+    öüóőúéáűí
+"""
+
+@pytest.mark.version('>=3.0.10')
+def test_1(act: Action):
+    test_script = """
+        set list on;
+        set blob all;
+        create table test (txt varchar(10) character set win1250 collate pxw_hundc);
+        insert into test(txt) values ('öüóőúéáűí');
+        select cast(null as blob sub_type 1) as blob_id
+        from rdb$database
+        union all
+        select txt
+        from test;
+    """
+
+    act.expected_stdout = expected_stdout
+    act.isql(switches=['-q'], charset = 'utf8', input = test_script, combine_output = True)
+    assert act.clean_stdout == act.clean_expected_stdout