Use -f in Perl instead of ls for checking if a file exists

contrib/pg_tde/t/001_basic.pl

@@ -50,11 +50,10 @@ PGTDE::psql($node, 'postgres', 'SELECT * FROM test_enc ORDER BY id ASC;');
 my $tablefile = $node->data_dir . '/'
   . $node->safe_psql('postgres', "SELECT pg_relation_filepath('test_enc');");
 
-my $strings = 'TABLEFILE FOUND: ';
-$strings .= `(ls  $tablefile >/dev/null && echo yes) || echo no`;
-PGTDE::append_to_result_file($strings);
+PGTDE::append_to_result_file(
+	'TABLEFILE FOUND: ' . (-f $tablefile ? 'yes' : 'no'));
 
-$strings = 'CONTAINS FOO (should be empty): ';
+my $strings = 'CONTAINS FOO (should be empty): ';
 $strings .= `strings $tablefile | grep foo`;
 PGTDE::append_to_result_file($strings);
 

contrib/pg_tde/t/007_tde_heap.pl

@@ -108,15 +108,17 @@ sub verify_table
 	PGTDE::psql($node, 'postgres',
 		'SELECT * FROM ' . $table . ' ORDER BY id ASC;');
 
-	my $strings = 'TABLEFILE FOR ' . $table . ' FOUND: ';
-	$strings .= `(ls  $tablefile >/dev/null && echo -n yes) || echo -n no`;
-	PGTDE::append_to_result_file($strings);
+	PGTDE::append_to_result_file('TABLEFILE FOR '
+		  . $table
+		  . ' FOUND: '
+		  . (-f $tablefile ? 'yes' : 'no'));
 
-	$strings = 'CONTAINS FOO (should be empty): ';
+	my $strings = 'CONTAINS FOO (should be empty): ';
 	$strings .= `strings $tablefile | grep foo`;
 	PGTDE::append_to_result_file($strings);
 }
 
+# Verify that we can't see the data in the files
 verify_table('test_enc1');
 verify_table('test_enc2');
 verify_table('test_enc3');

contrib/pg_tde/t/expected/001_basic.out

@@ -38,7 +38,6 @@ SELECT * FROM test_enc ORDER BY id ASC;
 (2 rows)
 
 TABLEFILE FOUND: yes
-
 CONTAINS FOO (should be empty): 
 DROP TABLE test_enc;
 DROP EXTENSION pg_tde;