Learning Jazzer (for fuzz testing)

Just one of the things I'm learning. https://github.com/hchiam/learning

Jazzer.js (Jazzer) for fuzzing, AKA fuzz testing.

With node.js

https://www.youtube.com/watch?v=KyIhxEiNnfc

npm install -DE @jazzer.js/core

You can fuzz test FuzzTarget.js directly in the CLI with:

npx jazzer FuzzTarget.js

Use the Base64 code to reproduce a specific error, like npx jazzer FuzzTarget crash-s0m3cr4sh5tr1ng1d:

# still triggers ==54827== Uncaught Exception after Running:
npx jazzer FuzzTarget crash-eff8ec10351afe6a12d58df3e9c71e363a37ee55

# this one no longer shows error after Running:
npx jazzer FuzzTarget crash-ca6ca17b1b8bc4b9e134f498f97a406593824b90

Or with jest

https://www.youtube.com/watch?v=akSBP4fwgjg

npm install -DE @jazzer.js/jest-runner

(Or with yarn: yarn add --dev @jazzer.js/jest-runner)

You can fuzz test FuzzTarget.js by making jest run the fuzz test file FuzzTarget.fuzz.js

Make sure you also set up the following fuzz and jest options in your package.json:

{
  "scripts": {
    "fuzz": "JAZZER_FUZZ=1 jest --testRunner=\"@jazzer.js/jest-runner\" --testMatch=\"<rootDir>/**/*.fuzz.js\"",
    "fuzz_regression": "JAZZER_FUZZ=0 jest --testRunner=\"@jazzer.js/jest-runner\" --testMatch=\"<rootDir>/**/*.fuzz.js\"",
    // fuzz_regression checks against previously-found failures since jazzer stores bugs it found earlier
    "test": "jest --bail --findRelatedTests *.test.js", // for NON-fuzz tests. or for both test and fuzz: jest --testPathMatch=\"integration.test.js\"
    ...
  },
  ...
  "jest": { // the following makes running jest also auto-run the jest .fuzz tests:
    "projects": [
      {
        "displayName": "test"
      },
      {
        "testRunner": "@jazzer.js/jest-runner",
        "displayName": {
          "name": "Jazzer.js",
          "color": "cyan"
        },
        "testMatch": ["<rootDir>/**/*.fuzz.js"]
      }
    ]
  },
  ...
}

Or just: (to only run fuzz tests when you want)

{
  "scripts": {
    "fuzz": "JAZZER_FUZZ=1 jest --testRunner=\"@jazzer.js/jest-runner\" --testMatch=\"<rootDir>/**/*.fuzz.js\"",
    "fuzz_regression": "JAZZER_FUZZ=0 jest --testRunner=\"@jazzer.js/jest-runner\" --testMatch=\"<rootDir>/**/*.fuzz.js\"",
  ...
  },
  ...
}

Now you can run the following:

npm run fuzz

# check against previously-found failures since jazzer stores bugs it found earlier:
npm run fuzz_regression

# for NON-fuzz tests:
npm run test
# or for both test and fuzz: jest --testPathMatch=\"integration.test.js\"