diff --git a/packages/babel-helper-transform-fixture-test-runner/package.json b/packages/babel-helper-transform-fixture-test-runner/package.json
index 33c61b6450..718d442293 100644
--- a/packages/babel-helper-transform-fixture-test-runner/package.json
+++ b/packages/babel-helper-transform-fixture-test-runner/package.json
@@ -24,5 +24,8 @@
     "quick-lru": "5.1.0",
     "regenerator-runtime": "^0.13.7",
     "source-map": "^0.5.0"
+  },
+  "devDependencies": {
+    "@types/jest": "^25.2.2"
   }
 }
diff --git a/packages/babel-helper-transform-fixture-test-runner/src/helpers.js b/packages/babel-helper-transform-fixture-test-runner/src/helpers.ts
similarity index 100%
rename from packages/babel-helper-transform-fixture-test-runner/src/helpers.js
rename to packages/babel-helper-transform-fixture-test-runner/src/helpers.ts
diff --git a/packages/babel-helper-transform-fixture-test-runner/src/index.js b/packages/babel-helper-transform-fixture-test-runner/src/index.ts
similarity index 92%
rename from packages/babel-helper-transform-fixture-test-runner/src/index.js
rename to packages/babel-helper-transform-fixture-test-runner/src/index.ts
index 146f1ae904..5d11d54a3d 100644
--- a/packages/babel-helper-transform-fixture-test-runner/src/index.js
+++ b/packages/babel-helper-transform-fixture-test-runner/src/index.ts
@@ -14,6 +14,7 @@ import fs from "fs";
 import path from "path";
 import vm from "vm";
 import QuickLRU from "quick-lru";
+// @ts-ignore
 import escapeRegExp from "./escape-regexp.cjs";
 import { fileURLToPath } from "url";
 
@@ -69,10 +70,12 @@ function createContext() {
 function runCacheableScriptInTestContext(
   filename: string,
   srcFn: () => string,
-  context: Context,
-  moduleCache: Object,
+  // todo(flow->ts) was Context type, but it is missing
+  context: any,
+  moduleCache: any,
 ) {
-  let cached = cachedScripts.get(filename);
+  // todo(flow->ts) improve types
+  let cached: any = cachedScripts.get(filename);
   if (!cached) {
     const code = `(function (exports, require, module, __filename, __dirname) {\n${srcFn()}\n});`;
     cached = {
@@ -90,7 +93,9 @@ function runCacheableScriptInTestContext(
     produceCachedData: true,
   });
 
+  // @ts-expect-error todo(flow->ts) improve types
   if (script.cachedDataProduced) {
+    // @ts-expect-error todo(flow->ts) improve types
     cached.cachedData = script.cachedData;
   }
 
@@ -115,8 +120,9 @@ function runCacheableScriptInTestContext(
 function runModuleInTestContext(
   id: string,
   relativeFilename: string,
-  context: Context,
-  moduleCache: Object,
+  // todo(flow->ts) was Context type, but it is missing
+  context: any,
+  moduleCache: any,
 ) {
   const filename = require.resolve(id, {
     paths: [path.dirname(relativeFilename)],
@@ -148,7 +154,9 @@ function runModuleInTestContext(
  */
 export function runCodeInTestContext(
   code: string,
-  opts: { filename: string },
+  opts: {
+    filename: string;
+  },
   context = sharedTestContext,
 ) {
   const filename = opts.filename;
@@ -192,7 +200,8 @@ function run(task) {
     stderr,
   } = task;
 
-  function getOpts(self) {
+  // todo(flow->ts) add proper return type (added any, because empty object is inferred)
+  function getOpts(self): any {
     const newOpts = merge(
       {
         ast: true,
@@ -226,7 +235,7 @@ function run(task) {
     } catch (err) {
       // Pass empty location to include the whole file in the output.
       err.message =
-        `${exec.loc}: ${err.message}\n` + codeFrameColumns(execCode, {});
+        `${exec.loc}: ${err.message}\n` + codeFrameColumns(execCode, {} as any);
       throw err;
     }
   }
@@ -336,7 +345,7 @@ function validateFile(actualCode, expectedLoc, expectedCode) {
   }
 }
 
-function normalizeOutput(code, normalizePathSeparator) {
+function normalizeOutput(code, normalizePathSeparator?) {
   const projectRoot = path.resolve(
     path.dirname(fileURLToPath(import.meta.url)),
     "../../../",
@@ -391,11 +400,21 @@ expect.extend({
   },
 });
 
+declare global {
+  // eslint-disable-next-line no-redeclare,@typescript-eslint/no-unused-vars
+  namespace jest {
+    // eslint-disable-next-line @typescript-eslint/no-unused-vars
+    interface Matchers<R> {
+      toEqualFile({ filename, code }): jest.CustomMatcherResult;
+    }
+  }
+}
+
 export default function (
   fixturesLoc: string,
   name: string,
-  suiteOpts = {},
-  taskOpts = {},
+  suiteOpts: any = {},
+  taskOpts: any = {},
   dynamicOpts?: Function,
 ) {
   const suites = getFixtures(fixturesLoc);
@@ -432,6 +451,7 @@ export default function (
 
             if (dynamicOpts) dynamicOpts(task.options, task);
 
+            // @ts-expect-error todo(flow->ts) missing property
             if (task.externalHelpers) {
               (task.options.plugins ??= []).push([
                 "external-helpers",
diff --git a/yarn.lock b/yarn.lock
index 54e64c182c..0c7429fa25 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -821,6 +821,7 @@ __metadata:
     "@babel/code-frame": "workspace:^7.12.13"
     "@babel/core": "workspace:^7.13.10"
     "@babel/helper-fixtures": "workspace:^7.13.10"
+    "@types/jest": ^25.2.2
     babel-check-duplicated-nodes: ^1.0.0
     escape-string-regexp: "condition:BABEL_8_BREAKING ? ^4.0.0 : "
     lodash: ^4.17.19
@@ -3713,6 +3714,18 @@ __metadata:
   languageName: node
   linkType: hard
 
+"@jest/types@npm:^25.5.0":
+  version: 25.5.0
+  resolution: "@jest/types@npm:25.5.0"
+  dependencies:
+    "@types/istanbul-lib-coverage": ^2.0.0
+    "@types/istanbul-reports": ^1.1.1
+    "@types/yargs": ^15.0.0
+    chalk: ^3.0.0
+  checksum: 33ad68320efb297c4bd98975105130e1b4096d631decfc5a093691e24f27fce0410b4a7c5a87b736873271ebc003e48e853529587e584b3152efca572139a4a3
+  languageName: node
+  linkType: hard
+
 "@jest/types@npm:^26.6.1":
   version: 26.6.1
   resolution: "@jest/types@npm:26.6.1"
@@ -4041,6 +4054,16 @@ __metadata:
   languageName: node
   linkType: hard
 
+"@types/istanbul-reports@npm:^1.1.1":
+  version: 1.1.2
+  resolution: "@types/istanbul-reports@npm:1.1.2"
+  dependencies:
+    "@types/istanbul-lib-coverage": "*"
+    "@types/istanbul-lib-report": "*"
+  checksum: 92bd1f76a4ce16f5390c80b6b0e657171faf0003b0ff370b3c37739087c825d664493c9debf442c0871d864f1be15c88460f2399ae748186d1a944f16958aea4
+  languageName: node
+  linkType: hard
+
 "@types/istanbul-reports@npm:^3.0.0":
   version: 3.0.0
   resolution: "@types/istanbul-reports@npm:3.0.0"
@@ -4050,6 +4073,16 @@ __metadata:
   languageName: node
   linkType: hard
 
+"@types/jest@npm:^25.2.2":
+  version: 25.2.3
+  resolution: "@types/jest@npm:25.2.3"
+  dependencies:
+    jest-diff: ^25.2.1
+    pretty-format: ^25.2.1
+  checksum: fe92624fd7b3b5358ffba8e59108b484de1d01df08dfc66bb597d59d09900db1950717adb8d42ce5f81ba615fa0b8de55fd5446808d92f75b45e08fcbe4cec6e
+  languageName: node
+  linkType: hard
+
 "@types/jsesc@npm:^2.5.0":
   version: 2.5.1
   resolution: "@types/jsesc@npm:2.5.1"
@@ -6102,6 +6135,16 @@ __metadata:
   languageName: node
   linkType: hard
 
+"chalk@npm:^3.0.0":
+  version: 3.0.0
+  resolution: "chalk@npm:3.0.0"
+  dependencies:
+    ansi-styles: ^4.1.0
+    supports-color: ^7.1.0
+  checksum: 4018b0c812880da595d0d7b8159939527b72f58d3370e2fdc1a24d9abd460bab851695d7eca014082f110d5702d1221b05493fec430ccce375de907d50cc48c1
+  languageName: node
+  linkType: hard
+
 "char-regex@npm:^1.0.2":
   version: 1.0.2
   resolution: "char-regex@npm:1.0.2"
@@ -6975,6 +7018,13 @@ __metadata:
   languageName: node
   linkType: hard
 
+"diff-sequences@npm:^25.2.6":
+  version: 25.2.6
+  resolution: "diff-sequences@npm:25.2.6"
+  checksum: 332484fc00f6beca726d8dbc13095f6006527002bef936a07b4e6bbec681fbaac484e1a7ea4e9ab0d53e375d1cde9e642c8cce31dfe6329cfdf8f01f26b17505
+  languageName: node
+  linkType: hard
+
 "diff-sequences@npm:^26.5.0":
   version: 26.5.0
   resolution: "diff-sequences@npm:26.5.0"
@@ -9821,6 +9871,18 @@ fsevents@^1.2.7:
   languageName: node
   linkType: hard
 
+"jest-diff@npm:^25.2.1":
+  version: 25.5.0
+  resolution: "jest-diff@npm:25.5.0"
+  dependencies:
+    chalk: ^3.0.0
+    diff-sequences: ^25.2.6
+    jest-get-type: ^25.2.6
+    pretty-format: ^25.5.0
+  checksum: 14a2634ecb159a9a2f061239db1cea0c889e7a72ab05bd1fa799db30efca2ce79291372823f5e3468d9bc856f404f312e44e89c171eea8132b5835d12f71d0b3
+  languageName: node
+  linkType: hard
+
 "jest-diff@npm:^26.6.1":
   version: 26.6.1
   resolution: "jest-diff@npm:26.6.1"
@@ -9884,6 +9946,13 @@ fsevents@^1.2.7:
   languageName: node
   linkType: hard
 
+"jest-get-type@npm:^25.2.6":
+  version: 25.2.6
+  resolution: "jest-get-type@npm:25.2.6"
+  checksum: 6051fcb75cdaa8fad66fd5a1e91d2c1597e9ccc54eecd5cd489fd73a00e322d28cb5859b656a8224a41eddab0ecfb875df9ec62f545a76afa1a55d3ba97fba6d
+  languageName: node
+  linkType: hard
+
 "jest-get-type@npm:^26.3.0":
   version: 26.3.0
   resolution: "jest-get-type@npm:26.3.0"
@@ -12243,6 +12312,18 @@ fsevents@^1.2.7:
   languageName: node
   linkType: hard
 
+"pretty-format@npm:^25.2.1, pretty-format@npm:^25.5.0":
+  version: 25.5.0
+  resolution: "pretty-format@npm:25.5.0"
+  dependencies:
+    "@jest/types": ^25.5.0
+    ansi-regex: ^5.0.0
+    ansi-styles: ^4.0.0
+    react-is: ^16.12.0
+  checksum: f7cc631d51e22c809d429d20facfd886ba0b212d419d153467872f68688256c2c55563bf70e943b7347ec9180b41a1d19c4235dc171850f9d5382a52959c0245
+  languageName: node
+  linkType: hard
+
 "pretty-format@npm:^26.6.1":
   version: 26.6.1
   resolution: "pretty-format@npm:26.6.1"
@@ -12441,6 +12522,13 @@ fsevents@^1.2.7:
   languageName: node
   linkType: hard
 
+"react-is@npm:^16.12.0":
+  version: 16.13.1
+  resolution: "react-is@npm:16.13.1"
+  checksum: 11bcf1267a314a522615f626f3ce3727a3a24cdbf61c4d452add3550a7875326669631326cfb1ba3e92b6f72244c32ffecf93ad21c0cad8455d3e169d0e3f060
+  languageName: node
+  linkType: hard
+
 "react-is@npm:^17.0.1":
   version: 17.0.1
   resolution: "react-is@npm:17.0.1"