How to test Mojolicious applications in Perl?

Testing Mojolicious applications usually relies on Mojolicious and its testing module Test::Mojo. However, if your environment does not have Mojolicious installed (which appears to be the case in your sandbox), you won’t be able to use Mojo-specific modules like Mojo::Base or Test::Mojo.

In such constrained sandbox environments without external modules like Mojolicious, the best you can do is simulate a minimal HTTP app-like structure using core Perl features, or focus on pure Perl logic testing. Full Mojolicious app testing requires the framework installed because it is not part of the Perl core distribution.

Below is a simplified example of how you can write a very basic test script for a minimal subroutine-based “app” in pure Perl using Test::More (which is core since Perl 5.8). This example mimics the idea of request/response testing, but without Mojolicious.

Minimal Pure Perl “App” Testing with Test::More (No Mojolicious)

#!/usr/bin/env perl
use strict;
use warnings;
use Test::More tests => 4;

# A simple subroutine mimicking a web route handler
sub index_route {
    return "Hello World!";
}

sub echo_route {
    my ($params) = @_;
    my $name = $params->{name} // 'anonymous';
    return qq{{"message": "Hello, $name"}};
}

# Test 1: index_route returns expected text
is(index_route(), "Hello World!", "GET / returns 'Hello World!'");

# Test 2: echo_route with name param
is(echo_route({ name => 'Alice' }), '{"message": "Hello, Alice"}', "POST /echo with name");

# Test 3: echo_route without name param defaults to 'anonymous'
is(echo_route({}), '{"message": "Hello, anonymous"}', "POST /echo without name param");

# Test 4: echo_route with undef parameter (also defaults)
is(echo_route(), '{"message": "Hello, anonymous"}', "POST /echo with no param");

done_testing();

Explanation and Key Points

• This code mimics web endpoints as Perl subroutines rather than real HTTP requests.
• Test::More is used to verify outputs of these subroutines directly.
• The JSON responses are simple strings here, not real JSON objects—parsing/encoding would need extra modules (e.g., JSON::PP).
• This avoids all external dependencies and runs anywhere Perl core is available.
• While you lose the rich Mojolicious routing/testing capabilities, this method is useful for logic unit testing in restricted environments.

Why Your Mojolicious Tests Fail in Sandbox

• The Mojolicious modules (like Mojo::Base) are not part of the Perl core distribution—they must be installed separately from CPAN.
• Sandbox environments that disallow external modules or network/file access cannot run Mojolicious tests as is.
• Thus, direct Mojolicious app testing is impossible without those dependencies.

Summary: To test Mojolicious apps properly, you need Mojolicious installed. For sandboxed environments without it, focus on testing pure Perl code logic or consider running tests on a local machine with the proper environment configured.