test(code): add test for API request error

tests/code-api-request-error.t

@@ -0,0 +1,64 @@
+#!/usr/bin/env perl
+
+use strict;
+use warnings;
+use Test::More;
+use Test::Exception;
+use Test::MockObject;
+use Test::Output;
+use Capture::Tiny qw(capture_stdout);
+
+{
+    package Mojo::UserAgent;
+    use Test::MockObject;
+
+    my $mock_response;
+
+    sub new {
+        my $class = shift;
+        return Test::MockObject -> new -> mock('get', sub {
+            my ($self, $url, $headers) = @_;
+            return Test::MockObject -> new -> mock('result', sub {
+                return $mock_response;
+            });
+        });
+    }
+
+    sub set_mock_response {
+        my ($class, $response) = @_;
+        $mock_response = $response;
+        return $mock_response;
+    }
+}
+
+use lib '../lib';
+use SecurityGate::Engine::Code;
+
+subtest 'API request error' => sub {
+    plan tests => 2;
+
+    my $mock_response = Mojo::UserAgent -> set_mock_response(Test::MockObject -> new);
+    $mock_response -> set_always('code', 401);
+
+    my %severity_limits = (
+        critical => 0,
+        high     => 0,
+        medium   => 0,
+        low      => 0
+    );
+
+    my $result;
+    my $error_message = qr/Error: \s Unable \s to \s fetch \s code \s scanning \s alerts\./x;
+    my $status_code = qr/\s HTTP \s status \s code: \s 401/x;
+    my $full_error_pattern = qr/$error_message$status_code/x;
+
+    stdout_like(
+        sub { $result = SecurityGate::Engine::Code -> new('test_token', 'test_repo', \%severity_limits) },
+        $full_error_pattern,
+        'Correct error message for API request failure'
+    );
+
+    is($result, 1, 'Returns 1 when API request fails');
+};
+
+done_testing();