diff --git a/tests/bugs/gh_8178_addi_test.py b/tests/bugs/gh_8178_addi_test.py
new file mode 100644
index 00000000..cbceb042
--- /dev/null
+++ b/tests/bugs/gh_8178_addi_test.py
@@ -0,0 +1,117 @@
+#coding:utf-8
+
+"""
+ID:          issue-8178
+ISSUE:       https://github.com/FirebirdSQL/firebird/pull/8178
+TITLE:       Check result of conversion to string in COALESCE that involves all families of data types.
+DESCRIPTION:
+    Additional test for gh_8178
+NOTES:
+    [12.07.2024] pzotov
+    Checked on 6.0.0.392, 5.0.1.1434, 4.0.5.3127, 3.0.12.33765
+"""
+
+import pytest
+from firebird.qa import *
+
+db = db_factory()
+
+test_script = """
+    set list on;
+    recreate table dvalues(
+        t_int int default 12345
+       ,t_boo boolean default true
+       ,t_chr char default 'A'
+       ,t_blb blob default 'bbbbbbblllllllloooooooooobbbbbbbb'
+       ,t_dat date default '01.01.1991'
+       ,t_tim time default '01:02:03.456'
+       ,t_tst timestamp default '01.02.2003 23:34:56'
+       ,t_nul char default null
+    );
+    insert into dvalues default values;
+    commit;
+    ---------------------------------------------------------
+    recreate table dtypes(f smallint, t varchar(20));
+    insert into dtypes(f,t) values( 1,'int');
+    insert into dtypes(f,t) values( 2,'boo');
+    insert into dtypes(f,t) values( 3,'chr');
+    insert into dtypes(f,t) values( 4,'blb');
+    insert into dtypes(f,t) values( 5,'dat');
+    insert into dtypes(f,t) values( 6,'tim');
+    insert into dtypes(f,t) values( 7,'tst');
+    --insert into dtypes(f,t) values( 8,'nul');
+    commit;
+
+    set count on;
+
+    set term ^;
+    execute block returns( checked_expr varchar(1024), raised_gds int) as
+        declare v_expr varchar(1024);
+        declare v_done smallint;
+    begin
+        for
+            select
+                --a.t as a_t, b.t as b_t, c.t as c_t, d.t as d_t, e.t as e_t, f.t as f_t, g.t as g_t
+                --,a.f as a_f, b.f as b_f, c.f as c_f, d.f as d_f, e.f as e_f, f.f as f_f, g.f as g_f,
+                'select iif( coalesce('
+                 ||
+                 iif( a.t = 'nul',   'null',   't_'||a.t)
+                 ||
+                 iif( b.t = 'nul', ', null', ', t_'||b.t)
+                 ||
+                 iif( c.t = 'nul', ', null', ', t_'||c.t)
+                 ||
+                 iif( d.t = 'nul', ', null', ', t_'||d.t)
+                 ||
+                 iif( e.t = 'nul', ', null', ', t_'||e.t)
+                 ||
+                 iif( f.t = 'nul', ', null', ', t_'||f.t)
+                 ||
+                 iif( g.t = 'nul', ', null', ', t_'||g.t)
+                 ||
+                 ') is distinct from null, 1, 0 ) as x from dvalues' as expr
+            from dtypes a
+            cross join dtypes b
+            cross join dtypes c
+            cross join dtypes d
+            cross join dtypes e
+            cross join dtypes f
+            cross join dtypes g
+            where
+                a.f not in (b.f, c.f, d.f, e.f, f.f, g.f)
+            and b.f not in (c.f, d.f, e.f, f.f, g.f)
+            and c.f not in (d.f, e.f, f.f, g.f)
+            and d.f not in (e.f, f.f, g.f)
+            and e.f not in (f.f, g.f)
+            and f.f not in (g.f)
+            order by a.t, b.t, c.t, d.t, e.t, f.t, g.t
+            as cursor k
+        do begin
+           checked_expr = k.expr;
+           raised_gds = 0;
+           begin
+               execute statement checked_expr into v_done;
+               when any do
+               begin
+                   raised_gds = gdscode;
+               end
+           end
+           if (raised_gds <> 0) then
+               suspend;
+        end
+    end
+    ^
+    set term ;^
+"""
+
+act = isql_act('db', test_script)
+
+expected_stdout = """
+    Records affected: 0
+"""
+
+@pytest.mark.version('>=3.0.12')
+def test_1(act: Action):
+    act.expected_stdout = expected_stdout
+    act.execute(combine_output = True)
+    assert act.clean_stdout == act.clean_expected_stdout