diff --git a/src/bin/pg_walsummary/t/001_basic.pl b/src/bin/pg_walsummary/t/001_basic.pl
index 0d606075c1..4a1555091a 100644
--- a/src/bin/pg_walsummary/t/001_basic.pl
+++ b/src/bin/pg_walsummary/t/001_basic.pl
@@ -1,7 +1,7 @@
 # Copyright (c) 2021-2024, PostgreSQL Global Development Group
 
 use strict;
-use warnings;
+use warnings FATAL => 'all';
 use PostgreSQL::Test::Utils;
 use Test::More;
 
diff --git a/src/bin/pg_walsummary/t/002_blocks.pl b/src/bin/pg_walsummary/t/002_blocks.pl
index a3e3aebd32..0fddbaa22f 100644
--- a/src/bin/pg_walsummary/t/002_blocks.pl
+++ b/src/bin/pg_walsummary/t/002_blocks.pl
@@ -1,7 +1,7 @@
 # Copyright (c) 2021-2024, PostgreSQL Global Development Group
 
 use strict;
-use warnings;
+use warnings FATAL => 'all';
 use File::Compare;
 use PostgreSQL::Test::Cluster;
 use PostgreSQL::Test::Utils;
diff --git a/src/common/unicode/generate-unicode_case_table.pl b/src/common/unicode/generate-unicode_case_table.pl
index e09ccffd42..508b05af8e 100644
--- a/src/common/unicode/generate-unicode_case_table.pl
+++ b/src/common/unicode/generate-unicode_case_table.pl
@@ -9,7 +9,7 @@
 # Copyright (c) 2000-2024, PostgreSQL Global Development Group
 
 use strict;
-use warnings;
+use warnings FATAL => 'all';
 use Getopt::Long;
 
 use FindBin;
diff --git a/src/test/modules/test_json_parser/t/001_test_json_parser_incremental.pl b/src/test/modules/test_json_parser/t/001_test_json_parser_incremental.pl
index 30506be033..abf0d7a237 100644
--- a/src/test/modules/test_json_parser/t/001_test_json_parser_incremental.pl
+++ b/src/test/modules/test_json_parser/t/001_test_json_parser_incremental.pl
@@ -5,7 +5,7 @@
 
 
 use strict;
-use warnings;
+use warnings FATAL => 'all';
 
 use PostgreSQL::Test::Utils;
 use Test::More;
diff --git a/src/test/modules/test_json_parser/t/002_inline.pl b/src/test/modules/test_json_parser/t/002_inline.pl
index 7c4134b3a6..8d62eb44c8 100644
--- a/src/test/modules/test_json_parser/t/002_inline.pl
+++ b/src/test/modules/test_json_parser/t/002_inline.pl
@@ -5,7 +5,7 @@
 # for a variety of small inputs.
 
 use strict;
-use warnings;
+use warnings FATAL => 'all';
 
 use PostgreSQL::Test::Utils;
 use Test::More;
diff --git a/src/test/modules/test_json_parser/t/003_test_semantic.pl b/src/test/modules/test_json_parser/t/003_test_semantic.pl
index 7d3e07e750..74e0fa5bb1 100644
--- a/src/test/modules/test_json_parser/t/003_test_semantic.pl
+++ b/src/test/modules/test_json_parser/t/003_test_semantic.pl
@@ -5,7 +5,7 @@
 # output with the expected output.
 
 use strict;
-use warnings;
+use warnings FATAL => 'all';
 
 use PostgreSQL::Test::Utils;
 use Test::More;
diff --git a/src/test/modules/test_json_parser/t/004_test_parser_perf.pl b/src/test/modules/test_json_parser/t/004_test_parser_perf.pl
index e82bb3695b..81b8c8ae42 100644
--- a/src/test/modules/test_json_parser/t/004_test_parser_perf.pl
+++ b/src/test/modules/test_json_parser/t/004_test_parser_perf.pl
@@ -7,7 +7,7 @@
 # of iterations instead of just one.
 
 use strict;
-use warnings;
+use warnings FATAL => 'all';
 
 use PostgreSQL::Test::Utils;
 use Test::More;
diff --git a/src/test/modules/test_misc/t/005_timeouts.pl b/src/test/modules/test_misc/t/005_timeouts.pl
index a792610231..9e1ff9e5c1 100644
--- a/src/test/modules/test_misc/t/005_timeouts.pl
+++ b/src/test/modules/test_misc/t/005_timeouts.pl
@@ -2,7 +2,7 @@
 # Copyright (c) 2024, PostgreSQL Global Development Group
 
 use strict;
-use warnings;
+use warnings FATAL => 'all';
 use locale;
 
 use PostgreSQL::Test::Cluster;
diff --git a/src/test/recovery/t/040_standby_failover_slots_sync.pl b/src/test/recovery/t/040_standby_failover_slots_sync.pl
index f0bf0ddc12..3b6dddba71 100644
--- a/src/test/recovery/t/040_standby_failover_slots_sync.pl
+++ b/src/test/recovery/t/040_standby_failover_slots_sync.pl
@@ -2,7 +2,7 @@
 # Copyright (c) 2024, PostgreSQL Global Development Group
 
 use strict;
-use warnings;
+use warnings FATAL => 'all';
 use PostgreSQL::Test::Cluster;
 use PostgreSQL::Test::Utils;
 use Test::More;
diff --git a/src/test/recovery/t/041_checkpoint_at_promote.pl b/src/test/recovery/t/041_checkpoint_at_promote.pl
index 7c307314ea..5aa05b456c 100644
--- a/src/test/recovery/t/041_checkpoint_at_promote.pl
+++ b/src/test/recovery/t/041_checkpoint_at_promote.pl
@@ -2,7 +2,7 @@
 # Copyright (c) 2024, PostgreSQL Global Development Group
 
 use strict;
-use warnings;
+use warnings FATAL => 'all';
 use PostgreSQL::Test::Cluster;
 use PostgreSQL::Test::Utils;
 use Time::HiRes qw(usleep);
diff --git a/src/test/recovery/t/042_low_level_backup.pl b/src/test/recovery/t/042_low_level_backup.pl
index 0a75a8624a..61d23187e0 100644
--- a/src/test/recovery/t/042_low_level_backup.pl
+++ b/src/test/recovery/t/042_low_level_backup.pl
@@ -5,7 +5,7 @@
 # to create backups.
 
 use strict;
-use warnings;
+use warnings FATAL => 'all';
 
 use File::Copy qw(copy);
 use File::Path qw(rmtree);