Install

App::Test::Generator is one Perl distribution with ten command-line tools. Nothing needs a daemon, a database or a network connection once it is installed; the only runtime service any part of it touches is the CPAN Testers API, and only when you ask for that part of the dashboard.

From CPAN

cpanm App::Test::Generator

That installs the module tree and puts fuzz-harness-generator, extract-schemas, test-generator-mutate, test-generator-index, generate-test-dashboard, benchmark-generator, pod-example-tester, deploy-workflows, instrument-modules and demo_extractor on your PATH.

From a checkout

git clone https://github.com/nigelhorne/App-Test-Generator.git
cd App-Test-Generator
perl Makefile.PL
make
make test
make install

prove -Ilib t runs the suite without installing anything. Two of the test files are opt-in integration tests and only run when EXTENDED_TESTING=1 is set:

EXTENDED_TESTING=1 TEST_JOBS=4 prove -Ilib t

t/app.t is the canary: it takes every module in lib/, extracts a schema from it, generates a fuzz harness and proves that harness. t/self-fuzz.t does the same through the installed command-line tools, so a change that breaks extraction or generation usually shows up there first.

Requirements

Needs	Why
Perl 5.036 or later	Declared as `MIN_PERL_VERSION`. The code uses signatures and `say`-era features without `feature` pragmas.
`Config::Abstraction` 0.36+	Reads the schema files, so YAML, JSON and Perl configuration all work.
`Params::Validate::Strict` 0.36+ and `Params::Get` 0.15+	Used both by ATG itself and by the harnesses it generates, to validate inputs against the schema.
`Return::Set` 0.03+	Validates the routine's return value in the generated test. 0.03 is the floor because list returns need it.
`PPI` and `Text::Balanced`	Schema extraction parses Perl source rather than guessing with regular expressions.
`Template`, `Data::Section::Simple`, `Data::Random*`, `Unicode::GCString`	The harness generator: templating, the embedded template body, and typed random data including grapheme-correct strings.
`YAML::XS`, `JSON::MaybeXS`	Reading schemas and writing `mutation.json` and the dashboard data files.
`Test::Most`	The generated `.t` files are Test::Most scripts.
`prove`	Shipped with Perl. `fuzz-harness-generator -r` and the mutation runner invoke it by absolute path, derived from `$^X`.

Optional modules that unlock features

These are declared as recommendations, not requirements. Each one is loaded at runtime, and its absence degrades a feature instead of breaking the install.

Module	What you get
`Devel::Cover` 1.51+	Coverage-guided fuzzing in `CoverageGuidedFuzzer` and the coverage columns in the dashboard. Without it, fuzzing runs blind — random only, no branch feedback.
`Test::LectroTest` and `Test::LectroTest::Compat`	Property-based tests. Both are in `TEST_REQUIRES`, so `make test` installs them; generated property tests skip themselves if they are missing.
`Type::Params` and `Types::Common`	Accurate schema extraction from `signature_for` declarations. Without them, extraction falls back to heuristics.
`BSD::Resource`	Applies a memory cap to the child process that evaluates a Type::Params signature. Not available on every platform, and not required anywhere else.
`Code::CutNPaste`-style CPD data	The duplication table and per-file duplication drill-downs, if `cover_html/cpd.json` exists.

# everything, including the optional features
cpanm --with-recommends App::Test::Generator

Verify the install

perl -MApp::Test::Generator -e 'print "$App::Test::Generator::VERSION\n"'
0.47

fuzz-harness-generator --version
extract-schemas --version
test-generator-mutate --version

Then generate a harness for the sample module and run it. This is the whole pipeline in two commands, and it needs nothing but the installed distribution:

extract-schemas lib/App/Test/Generator/Sample/Module.pm --output-dir /tmp/schemas
fuzz-harness-generator -r /tmp/schemas/greet.yml

fuzz-harness-generator -r writes the harness to a temporary file, runs it through prove, and prints Result: PASS followed by the TAP file and test counts. If you see that, the generator, the assertion libraries and your Perl all agree.

Windows

Everything works on Windows, with two differences. The close_stdin configuration option is ignored, because Windows has no equivalent of closing the inherited standard input. And the shell script generate-test-dashboard is a bash script — run it under Git Bash, MSYS2 or WSL, or run its individual steps by hand.