diff --git a/tools/testing/ktest/ktest.pl b/tools/testing/ktest/ktest.pl
index 89c2257bed98..ea43dd2f2fd5 100755
--- a/tools/testing/ktest/ktest.pl
+++ b/tools/testing/ktest/ktest.pl
@@ -684,11 +684,8 @@ sub set_value {
 	}
 	${$overrides}{$lvalue} = $prvalue;
     }
-    if ($rvalue =~ /^\s*$/) {
-	delete $opt{$lvalue};
-    } else {
-	$opt{$lvalue} = $prvalue;
-    }
+
+    $opt{$lvalue} = $prvalue;
 }
 
 sub set_eval {
@@ -3947,12 +3944,22 @@ for (my $i = 0, my $repeat = 1; $i <= $opt{"NUM_TESTS"}; $i += $repeat) {
     }
 }
 
+sub option_defined {
+    my ($option) = @_;
+
+    if (defined($opt{$option}) && $opt{$option} !~ /^\s*$/) {
+	return 1;
+    }
+
+    return 0;
+}
+
 sub __set_test_option {
     my ($name, $i) = @_;
 
     my $option = "$name\[$i\]";
 
-    if (defined($opt{$option})) {
+    if (option_defined($option)) {
 	return $opt{$option};
     }
 
@@ -3960,13 +3967,13 @@ sub __set_test_option {
 	if ($i >= $test &&
 	    $i < $test + $repeat_tests{$test}) {
 	    $option = "$name\[$test\]";
-	    if (defined($opt{$option})) {
+	    if (option_defined($option)) {
 		return $opt{$option};
 	    }
 	}
     }
 
-    if (defined($opt{$name})) {
+    if (option_defined($name)) {
 	return $opt{$name};
     }