Migrating from Mocha to the Tripwire Test Runner

This guide helps you move a Mocha test suite to the Tripwire CLI test runner (tripwire), which runs the same describe/it suites against node, browser and worker targets. It is written for both human readers and AI-assisted migrations (Copilot, Claude, and similar) – section 9 is a deterministic checklist and section 10 a machine-readable summary of every mapping below.

Related guides:

• Test Runner, CLI & Configuration - the full CLI/config reference
• Runner Troubleshooting - read this if you hit TypeScript Duplicate identifier/Subsequent variable declarations errors after installing tripwire
• Migrating from Chai / from node assert
  • for the assertions inside your tests, which this guide does not cover

---

1. Overview

Mocha and tripwire share the same test-definition vocabulary, so the test files themselves usually need no changes at all. What changes is the runner: the command you invoke, the config file it reads, and a handful of Mocha features that have no tripwire equivalent.

Area	Effort
Test files (describe/it/hooks)	None in most suites – see section 3 for the exceptions (context(), specify())
Assertions	None if you already use tripwire/chai-shim; otherwise see the assertion guides above
npm scripts / CLI flags	Low - mostly a 1:1 flag rename, see section 4
.mocharc.* config	Low - rewrite as .tripwirerc, see section 5
--parallel, root hook plugins, reporter options	Not supported - see section 7
TypeScript @types/mocha in the same project (or @types/jest/@types/jasmine)	None - installing tripwire declares no globals, so nothing breaks. Its global names are opt-in, and opting in while the other package is present is the one combination that clashes – see section 2

---

2. Install and switch the command

npm install @nevware21/tripwire --save-dev

The tripwire CLI is exposed through the package’s bin entry, so it is available to npm scripts (and npx) immediately.

Before (package.json):

{
    "scripts": {
        "test": "mocha \"test/**/*.test.js\"",
        "test:ts": "ts-mocha -p ./test/tsconfig.json \"test/**/*.test.ts\""
    }
}

After:

{
    "scripts": {
        "test": "tripwire \"test/**/*.test.js\"",
        "test:ts": "tripwire -p ./test/tsconfig.json \"test/**/*.test.ts\""
    }
}

TypeScript needs no separate runner: tripwire transpiles .ts test files on load through its own require hook (no ts-node/ts-mocha dependency). --project/-p selects the tsconfig, exactly as ts-mocha’s -p did; --tsProject/--ts-project are accepted as aliases so an existing ts-mocha command line usually works unchanged. Add --type-check to fail the run on type errors; --transpile-only is the default and turns checking back off. They are exact opposites writing one setting, so the last one on the command line wins, and either beats a config-file typeCheck. ts-mocha’s own --type-check and --transpile-only therefore carry across with the same meaning.

--type-check checks the tsconfig project, while the run executes whatever the glob matched – and during a migration those two are unusually likely to disagree, since the glob came from the Mocha command line and the tsconfig did not. A file outside the project’s include/files still runs, just unchecked; tripwire warns and names the files when that happens. Add --strict-type-check in CI to make it a failure instead of a warning. See what --type-check actually checks.

Quote your globs. As with Mocha, let the runner expand the pattern rather than the shell.

TypeScript: the global describe/it names

The runner installs the globals itself, so nothing changes at runtime. TypeScript is the part that needs a decision, because installing tripwire declares no ambient globals – deliberately, so that it can sit next to @types/mocha (or @types/jest/@types/jasmine) during the migration without breaking the build.

While @types/mocha is still installed, leave the globals alone. The bare describe/it in your existing files keep resolving to mocha’s declarations and keep compiling; tripwire’s runner supplies the matching functions at runtime. Nothing to configure.

Once @types/mocha is gone (npm uninstall @types/mocha), the bare names have no declaration, so opt in to tripwire’s:

// tsconfig.json -- keep every other entry the project relies on
{ "compilerOptions": { "types": ["node", "@nevware21/tripwire/globals"] } }

Adding @nevware21/tripwire-globals as a dependency and listing that instead is equivalent, as is a /// <reference types="@nevware21/tripwire/globals" /> in any single file. Alternatively, skip the globals and import the names per file – import { describe, it } from "@nevware21/tripwire" – which works with or without the other @types package present.

Opting in before removing the other package is the one combination that fails; see Runner Troubleshooting.

Run the same suite in a real browser or a Web Worker – the main reason to adopt the runner:

tripwire --target browser "test/**/*.test.ts"
tripwire --target worker  "test/**/*.test.ts"

---

3. Test file API

Every one of these works exactly as it does in Mocha, as a global (installed by the runner, typed via the opt-in globals entry) or as a named import from @nevware21/tripwire:

Mocha	Tripwire	Notes
describe / it	✅ same
describe.only / it.only	✅ same	Also fdescribe/fit (Jasmine style)
describe.skip / it.skip	✅ same	Also xdescribe/xit
it("pending") (no callback)	✅ same	Reported as pending
before / after / beforeEach / afterEach	✅ same	Also beforeAll/afterAll (Jasmine style)
Named hooks (before("name", fn))	✅ same	The name is used in hook-failure reports
suite / test (TDD interface)	✅ same	Available without a --ui flag
done callback (it("x", (done) => ...))	✅ same	Detected by function arity, as in Mocha
done(err) / done.fail(err)	✅ same
Returning a Promise / async test	✅ same
this.timeout(ms)	✅ same	Also settable per run with --timeout
this.slow(ms) / this.retries(n)	✅ same
this.skip()	✅ same	In a test or a hook
this.currentTest	⚠️ different shape	Exists in hooks, but is tripwire’s ITestCase (id, description, fn, only, skip, timeout, slow, retries) – Mocha’s .title, .state, .fullTitle() and .parent are undefined. Use .description for the title
context() / specify()	❌ not available	Rename to describe() / it()
xcontext() / xspecify()	❌ not available	Rename to xdescribe() / xit()
Root hook plugins (mochaHooks)	❌ not available	Declare the hook at the top level of a test file – see below

context/specify are the only commonly used Mocha aliases with no tripwire equivalent, and they fail loudly (the file fails to load with ReferenceError: context is not defined), so a find/replace before the first run is enough:

# context( -> describe(   and   specify( -> it(

Replacing root hook plugins

Every test file in a run is loaded into the same root suite, so a hook declared at the top level of any loaded file – outside every describe – applies to the entire run, which is what Mocha’s mochaHooks root hook plugin provided:

// test/root-hooks.test.js -- matched by the same glob as every other test file
beforeEach(function () {
    resetTestDatabase();
});

Do not put these in a --file/--require preload. On the node target a preload is require()d before the runner installs the globals and before the root suite exists, so beforeEach is not defined there and the file fails to load. (The browser/worker targets happen to load preloads as the first modules of the suite, after the globals exist, so a hook declared there does register – but relying on that makes the file break the moment it runs under --target node.) Preloads are for setup that does not touch the tripwire API (polyfills, environment variables, jsdom, and similar); a hook belongs in a file the run’s glob matches.

---

4. CLI flag mapping

Flags tripwire accepts with the same name and meaning as Mocha:

Mocha	Tripwire	Notes
--spec <glob>	--spec <glob>	Or just pass the glob positionally
--file <path>	--file <path>	Preloaded before the suite
--require <mod>, -r	--require <mod>, -r	node target: a module name or a path, as in Mocha. browser/worker: file paths only (./setup.ts) – see below
--grep <re>, -g	--grep <re>, -g
--fgrep <str>, -f	--fgrep <str>, -f
--invert	--invert
--bail, -b	--bail, -b
--timeout <ms>, -t	--timeout <ms>, -t
--slow <ms>, -s	--slow <ms>, -s
--retries <n>	--retries <n>
--reporter <name>	--reporter <name>	No -R short form. Repeatable/comma-separated for several at once. A custom reporter module is also accepted, node target only – see below
--watch	--watch	No -w short form. See the CLI guide for which targets it applies to
--ignore <glob> / --exclude <glob>	--ignore <glob>	Only the --ignore spelling
--help, -h	--help, -h

Preloads on the browser/worker targets. --require/--file values are resolved exactly as Mocha’s are on the node target (a package name such as jsdom-global/register, or a path). The browser and worker targets bundle the preload into the served module graph instead, and that currently accepts file paths only: a bare module name fails the run with Browser/worker preload currently supports file paths only. Write a small ./test/setup.ts that imports the package and pass that path instead.

List-valued flags (--spec, --ignore, --grep/--fgrep, --require/--file) add to the matching .tripwirerc list rather than replacing it; --reporter is the exception and replaces the file’s reporters. See section 5.

Renamed or replaced:

Mocha	Tripwire	Notes
--recursive	(none)	Use a recursive glob instead: "test/**/*.test.js"
--extension <ext>	(none)	Put the extension in the glob: "test/**/*.{js,ts}"
--config <path> / --package <path>	(none)	Config is discovered as .tripwirerc – see section 5
--ui bdd\|tdd	(none needed)	Both interfaces are always available
--list-reporters	--help	The help output lists every built-in reporter name
ts-mocha -p <tsconfig>	--project <tsconfig>, -p	--tsProject/--ts-project also accepted

Tripwire additions with no Mocha equivalent – see the CLI reference for the full list:

Flag	Purpose
--target <node\|browser\|worker>	Run the same suite in a browser or Web Worker
--fail-on-hook	Fail the run when a lifecycle hook fails – see Hook failures
--coverage, --coverage-reporter	Browser/worker coverage collection and reporting
--trace	Print each test and assertion as it executes
--show-files	Print the matched file list before running

Reporter names match Mocha’s built-in set, so --reporter values usually carry over unchanged: spec, dot, tap, json, json-stream, min, list, progress, landing, nyan, doc, markdown, xunit.

Custom reporters. As in Mocha, --reporter also takes a module – a path (./reporters/mine.js), a scoped package, or module:<package> for a bare package name (Mocha resolves bare names by trying the built-ins first; tripwire requires the prefix instead, so a mistyped built-in stays a typo). The module exports a listener, a { listener } object, or a createReporter(options) factory returning either – not a Mocha reporter class, whose runner.on("pass", ...) event names have no equivalent here. See Custom reporters. Applies to the node target; the browser and worker targets build their reporters inside the page/worker and take built-in names only.

Unrecognized flags are an error, not a warning. Anything starting with - that tripwire does not know fails the run with Unsupported option: --x and prints the usage. This is deliberate – a silently ignored --parallel would be worse – but it means leftover Mocha flags surface on the very first run rather than at some later point.

Note also that a bare -- does not introduce a passthrough argument list as it does for some runners: everything after it is treated as an additional file pattern (useful when a glob starts with -).

---

5. .mocharc.* → .tripwirerc

Tripwire does not read .mocharc.*. It looks for .tripwirerc, .tripwirerc.json, .tripwirerc.js/.cjs, tripwire.config.json, or tripwire.config.js/.cjs in every directory from the cwd up to the filesystem root, plus a ~/.tripwirerc-style file in the home directory, and merges them with the file closest to the cwd winning – so a monorepo can set shared defaults once at the root. Where several of those names exist in one directory, the one listed last wins. The list-valued fields spec, ignore, grep and require are concatenated across levels instead of replaced, and the matching CLI flags append to them too; every other setting is replaced by a CLI flag, as is reporters (--reporter replaces rather than adds). See Config Files for the full rules.

Before (.mocharc.json):

{
    "spec": ["test/**/*.test.ts"],
    "require": ["ts-node/register"],
    "timeout": 10000,
    "slow": 200,
    "retries": 1,
    "bail": false,
    "reporter": "spec",
    "ignore": ["**/fixtures/**"]
}

After (.tripwirerc):

// JSONC-style // comments are allowed
{
    "spec": ["test/**/*.test.ts"],
    // no ts-node/register -- tripwire transpiles .ts itself
    "project": "./test/tsconfig.json",
    "timeout": 10000,
    "slow": 200,
    "retries": 1,
    "bail": false,
    "failOnHook": true,
    "reporters": ["spec"],
    "ignore": ["**/fixtures/**"]
}

Field notes:

• reporter is accepted, but reporters (an array) is the documented name.
• Mocha’s .mocharc fgrep has no field of its own: grep (an array of regex strings, compiled case-insensitive) is the only pattern field, so escape a literal string yourself when moving an fgrep value into it. Every other setting has a config field; see the full field reference.

---

6. Assertions

The runner is independent of the assertion library your tests use – migrating the runner does not require migrating assertions in the same change. When you are ready:

• Coming from Chai: Migrating from Chai (a Chai 5 assert shim exists)
• Coming from node:assert: Migrating from node assert

Tripwire’s own assert/expect are installed as globals by the runner as well, so a migrated test file can drop the import entirely if you prefer – in TypeScript that needs the globals opt-in, and note that expect is one of the names @types/jest also declares.

---

7. Mocha features with no tripwire equivalent

Each of these fails the run with Unsupported option if left on the command line:

Mocha feature	Status	Suggested approach
--parallel, --jobs/-j	❌ Not supported	Runs are single-process. Note --target worker is unrelated – it means “run the suite inside a Web Worker”, not “run tests in parallel worker processes”
Root hook plugins (mochaHooks export)	❌ Not supported	Declare the hook at the top level of a loaded test file – see section 3. A --file/--require preload will not work on the node target: it runs before the globals exist
--reporter-option/-O	❌ Not supported	Reporter options are set programmatically; the CLI exposes --slow/--trace only
--forbid-only, --forbid-pending	❌ Not supported	Enforce with a lint rule or a review check
--check-leaks, --global	❌ Not supported
--delay	❌ Not supported
--dry-run	❌ Not supported	Use --grep with a non-matching pattern plus --show-files to inspect discovery
--sort	❌ Not supported	Files run in glob-resolution order
--async-only, --allow-uncaught	❌ Not supported
--color/--no-color, --inline-diffs	❌ Not supported	Color follows terminal/TTY detection
--full-trace	❌ Not supported	Test failures already carry their own stack. For a stack from the runner, which is otherwise hidden, use --debug-stack
--exit/--no-exit	❌ Not supported
--inspect, --node-option	❌ Not supported	Invoke node directly: node --inspect ./node_modules/.bin/tripwire ...

---

8. Behavior differences worth knowing

1. Hook failures. A before/after hook that throws stops its own suite and no more – the sibling suites run normally, as they do under Mocha. What differs is how it is counted: Mocha reports a broken hook as a failure, while tripwire records it separately on the run summary, so by default the run’s exit code still reflects test results alone and the suite’s own tests are reported as skipped rather than failed. Add --fail-on-hook to get Mocha-like “a broken hook fails the build” behavior (recommended in CI). Note it fails the run without stopping it – every suite still executes, unlike Mocha’s --bail.
2. Globals are installed by the runner, not by importing the package. Files loaded outside a tripwire run (a plain node file.js) see no describe; import from @nevware21/tripwire for that case, or import "@nevware21/tripwire/globals" to install the bare names. In TypeScript the bare names also need the globals opt-in to type-check. On the node target, --file/--require preloads run before the globals are installed, so they cannot call describe/it/hooks there (see section 3); on browser/worker they must be file paths, not package names.
3. The worker target is a Web Worker, and the browser target drives a real (headless Puppeteer, or manually opened) browser. Node-only APIs in shared test files need guarding.
4. --type-check is opt-in, and checks the project rather than the glob. By default .ts files are transpiled without type checking, so a type error that Mocha + ts-node would have surfaced only appears with --type-check. Even then, it checks the files the tsconfig resolves to – a matched file outside that project runs unchecked. Tripwire warns and names those files; --strict-type-check fails the run on them instead, which is what you want in CI.

---

9. Migration checklist

Deterministic order, safe to follow step by step (by a person or an agent):

1. npm install @nevware21/tripwire --save-dev
2. Replace mocha/ts-mocha with tripwire in every package.json script; keep the glob.
3. Map each remaining CLI flag using section 4. Delete unsupported ones (section 7).
4. If a .mocharc.* exists, rewrite it as .tripwirerc using section 5, then delete it.
5. grep the test tree for context(, specify(, xcontext(, xspecify( and rename them to describe(, it(, xdescribe(, xit(.
6. grep for mochaHooks and move any root hooks to the top level of a test file that the run’s glob already matches (not a --file preload – see section 3).
7. If the project is TypeScript, decide how the bare describe/it names are typed. While @types/mocha (or @types/jest/@types/jasmine) is still installed, leave it as-is – the existing declarations keep working. After uninstalling it, add "@nevware21/tripwire/globals" to compilerOptions.types (or depend on @nevware21/tripwire-globals), or import the names per file. Do not do both at once – see section 2 and Runner Troubleshooting.
8. Run the suite. Fix any Unsupported option: --x errors reported by step 3.
9. Add --fail-on-hook (or "failOnHook": true) to the CI script.
10. If the project is TypeScript and the CI script type-checks, add --strict-type-check too. The glob came from Mocha and the tsconfig did not, so any file the two disagree about runs unchecked – this is the step that catches it rather than warning about it. Fix whatever it reports by widening the tsconfig’s include, then leave the flag on.
11. Optional: add --target browser / --target worker scripts to run the same suite in a browser and a Web Worker.

---

10. Machine-readable summary

For automated migrations. Every entry is derived from the tables above.

{
  "package": "@nevware21/tripwire",
  "cliCommand": "tripwire",
  "replacesCommands": ["mocha", "ts-mocha"],
  "configFile": {
    "from": [".mocharc", ".mocharc.json", ".mocharc.yml", ".mocharc.js", ".mocharc.cjs"],
    "to": [".tripwirerc", ".tripwirerc.json", ".tripwirerc.js", ".tripwirerc.cjs", "tripwire.config.json", "tripwire.config.js", "tripwire.config.cjs"]
  },
  "flagsUnchanged": ["--spec", "--file", "--require", "-r", "--grep", "-g", "--fgrep", "-f", "--invert", "--bail", "-b", "--timeout", "-t", "--slow", "-s", "--retries", "--reporter", "--watch", "--ignore", "--help", "-h"],
  "flagsUnchangedNotes": {
    "--require": "node target: a module name or a path, as in Mocha; browser/worker targets accept file paths only (./setup.ts) -- a bare module name fails with 'Browser/worker preload currently supports file paths only'",
    "--file": "same path-only rule as --require on the browser/worker targets",
    "--fgrep": "no config field of its own; config files have only the grep array (regex strings)"
  },
  "configPrecedence": {
    "listValuedFlagsAppendToConfig": ["--spec", "--ignore", "--grep", "--fgrep", "--require", "--file", "--coverage-reporter", "--coverage-src"],
    "replacesConfigList": ["--reporter"],
    "configKeysConcatenatedAcrossDirectories": ["grep", "ignore", "spec", "require"],
    "otherSettings": "the CLI flag replaces the config value; a config file closer to the cwd replaces one higher up"
  },
  "flagsRenamed": {
    "--exclude": "--ignore",
    "-R": "--reporter",
    "-w": "--watch",
    "-p (ts-mocha)": "--project",
    "--list-reporters": "--help"
  },
  "flagsRemovedUseGlobInstead": ["--recursive", "--extension"],
  "flagsUnsupported": ["--parallel", "-j", "--jobs", "--config", "--package", "--ui", "-u", "--reporter-option", "-O", "--forbid-only", "--forbid-pending", "--check-leaks", "--global", "--globals", "--delay", "--dry-run", "--sort", "--async-only", "-A", "--allow-uncaught", "--color", "--no-color", "-c", "--inline-diffs", "--diff", "--no-diff", "--full-trace", "--exit", "--no-exit", "--inspect", "--inspect-brk", "--node-option", "--growl"],
  "unsupportedFlagBehavior": "run fails with 'Unsupported option: <flag>' and prints usage",
  "globalsUnchanged": ["describe", "it", "before", "after", "beforeEach", "afterEach", "beforeAll", "afterAll", "suite", "test", "fdescribe", "fit", "xdescribe", "xit", "assert", "expect"],
  "globalsRenamed": { "context": "describe", "specify": "it", "xcontext": "xdescribe", "xspecify": "xit" },
  "reporterNames": ["spec", "dot", "tap", "json", "json-stream", "min", "list", "progress", "landing", "nyan", "doc", "markdown", "xunit", "cargo"],
  "typescript": {
    "transpilesTestFilesItself": true,
    "dropDependencies": ["ts-node/register", "ts-mocha"],
    "projectFlag": "--project",
    "typeCheckFlag": "--type-check",
    "transpileOnlyFlag": "--transpile-only",
    "typeCheckDefault": false,
    "typeCheckConfigField": "typeCheck",
    "typeCheckFlagPrecedence": "--type-check and --transpile-only are opposites writing one setting; the last flag on the command line wins, and any CLI flag beats the config file typeCheck value",
    "typeCheckTargets": ["node", "browser", "worker"],
    "typeCheckScope": "the tsconfig project, not the run's glob -- a matched file outside the project's include/files runs unchecked and is warned about",
    "typeCheckScopeFlag": "--type-check-scope",
    "typeCheckScopeValues": ["project", "run"],
    "typeCheckScopeDefault": "project",
    "typeCheckScopeConfigField": "typeCheckScope",
    "strictTypeCheckFlag": "--strict-type-check",
    "compileCache": {
      "note": "tripwire has no mocha equivalent for these -- they are additions, not mappings, and nothing needs changing to adopt them",
      "targets": ["node"],
      "targetNote": "--emit-cache, --isolated-transpile, --incremental and --type-check-scope apply to the node target only; browser and worker compile their module graph every run and check the whole project",
      "location": "node_modules/.cache/tripwire, or a per-project temp directory when there is no node_modules; never inside the project tree",
      "reportedEveryRun": "a 'Compile cache: reused/rebuilt/isolated' line on every node run, naming what changed when it rebuilt",
      "flags": {
        "--emit-cache": { "configField": "emitCache", "default": true, "does": "reuse compiled output, and a clean type-check, between runs when no program input changed" },
        "--isolated-transpile": { "configField": "isolatedTranspile", "default": false, "does": "compile each file on its own rather than through a whole program when not type-checking", "cannot": "resolve an ambient 'declare const enum' from a dependency -- such a project fails at load with 'Cannot read properties of undefined'" },
        "--incremental": { "configField": "incremental", "default": false, "does": "keep TypeScript's own .tsbuildinfo state between runs", "note": "measured no benefit; --emit-cache supersedes it" },
        "--graph-thread": { "configField": "graphThread", "default": false, "does": "build the browser/worker module graph on a worker thread", "note": "measured no benefit; the build then competes for the CPU the browser needs to start" }
      }
    },
    "ambientGlobals": {
      "declaredByMainEntry": false,
      "note": "importing @nevware21/tripwire declares no globals, so it never clashes with @types/mocha, @types/jest or @types/jasmine",
      "optInForms": [
        "compilerOptions.types += \"@nevware21/tripwire/globals\"",
        "/// <reference types=\"@nevware21/tripwire/globals\" />",
        "import \"@nevware21/tripwire/globals\" (also installs the names at runtime)",
        "depend on @nevware21/tripwire-globals and use any of the three forms with that name"
      ],
      "alternative": "import { describe, it, assert, expect } from \"@nevware21/tripwire\" -- never clashes",
      "guide": "docs/runner-troubleshooting.md#cannot-find-name-describe"
    },
    "globalTypeClash": {
      "occursWhen": "the project opts in to tripwire's globals while @types/mocha, @types/jest or @types/jasmine is still in the program",
      "conflictsWith": ["@types/mocha", "@types/jest", "@types/jasmine"],
      "errors": ["TS2403 (mocha, jest)", "TS6200 (jasmine)"],
      "fixes": ["do not opt in -- import the names from @nevware21/tripwire instead", "uninstall the other @types package", "set compilerOptions.types to an allow-list excluding it", "set compilerOptions.skipLibCheck true"],
      "jestFollowUp": "once jest's types are gone, expect() is tripwire's -- jest matchers fail with TS2339 'Property toBe does not exist on type IAssertInst' and must be rewritten",
      "guide": "docs/runner-troubleshooting.md#typescript-duplicate-global-declarations"
    }
  },
  "rootHookPlugins": {
    "mochaHooksSupported": false,
    "replacement": "declare the hook at the top level of any test file matched by the run's glob -- all files share one root suite",
    "doNotUse": "--file / --require preloads: on the node target they run before the globals are installed and before the root suite exists, so a hook there fails to load (browser/worker load preloads after the globals exist, but a hook there breaks under --target node)"
  },
  "behaviorDifferences": [
    "hook failures are non-fatal unless --fail-on-hook is set",
    "--target worker means Web Worker, not parallel worker processes",
    "type checking of .ts test files is opt-in via --type-check",
    "--type-check covers the tsconfig project, not the run's glob -- use --strict-type-check to fail on the difference",
    "a failing run prints its message and hints, not a stack trace -- pass --debug-stack (or set TRIPWIRE_DEBUG_STACK=1) for the runner's own stack",
    "'--' starts additional file patterns, it is not a passthrough separator",
    "this.currentTest in a hook is tripwire's ITestCase (id, description, fn, only, skip, timeout, slow, retries) -- Mocha's .title, .state, .fullTitle() and .parent are undefined; use .description for the title",
    "--file/--require preloads cannot use describe/it/hooks on the node target (they load before the globals are installed); on browser/worker they must be file paths, not package names"
  ]
}

---

11. Coming from Jasmine or Jest instead

Jasmine. The suite/test/hook vocabulary is supported natively – beforeAll, afterAll, fdescribe, fit, xdescribe, xit are all available – so the migration follows the same steps above, with the CLI mapping being the only real work.

Jest. The describe/it/test/hook layer carries over unchanged, but everything built on jest’s expect and module system does not:

Jest API	Status
describe, it, test, beforeAll/afterAll/beforeEach/afterEach, .only/.skip, fit/xit/fdescribe/xdescribe	✅ Available as-is
expect(x).toBe(y) and every other matcher	❌ Different API – rewrite as expect(x).to.strictly.equal(y) / assert.strictEqual(x, y) (tripwire’s plain equal is loose ==); see the Jest guide for the full matcher mapping
jest.fn(), jest.mock(), jest.spyOn(), automatic mocking	❌ No equivalent – use a standalone mocking library (eg. sinon)
Snapshots (toMatchSnapshot)	❌ No equivalent
jest.useFakeTimers()	❌ No equivalent – use a standalone fake-timer library

Two jest-specific gotchas, both covered in Runner Troubleshooting:

1. @types/jest declares 12 of the same global names – more than @types/mocha’s 6 – because it also declares test and expect. Installing tripwire alongside it is still fine; what conflicts is opting in to tripwire’s globals while jest’s types are loaded. Migrating jest suites is therefore easiest without the opt-in: import { describe, it, expect } from "@nevware21/tripwire" in each converted file and leave jest’s declarations in place for the rest.
2. In a converted file expect(x).toBe(y) fails to compile with TS2339: Property 'toBe' does not exist on type 'IAssertInst', since expect now resolves to tripwire’s. That guide describes how to stage the rewrite per suite rather than all at once.

See the assertion guides for tripwire’s expect/assert vocabulary.