chore:add typecheck for tests of jest-snapshot

package.json

@@ -113,7 +113,7 @@
     "test": "yarn lint && yarn jest",
     "typecheck": "yarn typecheck:examples && yarn typecheck:tests",
     "typecheck:examples": "tsc -p examples/angular --noEmit && tsc -p examples/expect-extend --noEmit && tsc -p examples/typescript --noEmit",
-    "typecheck:tests": "tsc -b packages/{babel-jest,babel-plugin-jest-hoist,diff-sequences,expect,expect-utils,jest-circus,jest-cli,jest-config,jest-console}/src/{__tests__,init/__tests__}",
+    "typecheck:tests": "tsc -b packages/{babel-jest,babel-plugin-jest-hoist,diff-sequences,expect,expect-utils,jest-circus,jest-cli,jest-config,jest-console,jest-snapshot}/src/{__tests__,init/__tests__}",
     "verify-old-ts": "node ./scripts/verifyOldTs.mjs",
     "verify-pnp": "node ./scripts/verifyPnP.mjs",
     "watch": "yarn build:js && node ./scripts/watch.mjs",

packages/jest-snapshot/src/__tests__/InlineSnapshots.test.ts

@@ -19,7 +19,9 @@ jest.mock('prettier', () => {
     format: (text, opts) =>
       realPrettier.format(text, {
         pluginSearchDirs: [
-          require('path').dirname(require.resolve('prettier')),
+          (require('path') as typeof import('path')).dirname(
+            require.resolve('prettier'),
+          ),
         ],
         ...opts,
       }),

packages/jest-snapshot/src/__tests__/dedentLines.test.ts

@@ -11,12 +11,14 @@ import {dedentLines} from '../dedentLines';
 const $$typeof = Symbol.for('react.test.json');
 const plugins = [builtinPlugins.ReactTestComponent];
 
-const formatLines2 = val => format(val, {indent: 2, plugins}).split('\n');
-const formatLines0 = val => format(val, {indent: 0, plugins}).split('\n');
+const formatLines2 = (val: unknown) =>
+  format(val, {indent: 2, plugins}).split('\n');
+const formatLines0 = (val: unknown) =>
+  format(val, {indent: 0, plugins}).split('\n');
 
 describe('dedentLines non-null', () => {
   test('no lines', () => {
-    const indented = [];
+    const indented: Array<string> = [];
     const dedented = indented;
 
     expect(dedentLines(indented)).toEqual(dedented);
@@ -129,7 +131,7 @@ describe('dedentLines null', () => {
     ['object key multi-line', {'multi\nline\nkey': false}],
     ['object value multi-line', {key: 'multi\nline\nvalue'}],
     ['object key and value multi-line', {'multi\nline': '\nleading nl'}],
-  ])('%s', (name, val) => {
+  ])('%s', (_name, val) => {
     expect(dedentLines(formatLines2(val))).toBeNull();
   });
 

packages/jest-snapshot/src/__tests__/mockSerializer.test.ts

@@ -85,7 +85,7 @@ test('mock with 2 calls', () => {
 });
 
 test('indent option', () => {
-  const fn = jest.fn(val => val);
+  const fn = jest.fn((val: {key: string}) => val);
   fn({key: 'value'});
   const expected = [
     '[MockFunction] {',
@@ -110,7 +110,7 @@ test('indent option', () => {
 });
 
 test('min option', () => {
-  const fn = jest.fn(val => val);
+  const fn = jest.fn((val: {key: string}) => val);
   fn({key: 'value'});
   const expected =
     '[MockFunction] {"calls": [[{"key": "value"}]], "results": [{"type": "return", "value": {"key": "value"}}]}';

packages/jest-snapshot/src/__tests__/plugins.test.ts

@@ -5,13 +5,18 @@
  * LICENSE file in the root directory of this source tree.
  */
 
-beforeEach(() => jest.resetModules());
+import type {Plugin} from 'pretty-format';
+
+beforeEach(() => {
+  jest.resetModules();
+});
 
 const testPath = (names: Array<string>) => {
-  const {addSerializer, getSerializers} = require('../plugins');
+  const {addSerializer, getSerializers} =
+    require('../plugins') as typeof import('../plugins');
   const prev = getSerializers();
-  const added = names.map(name =>
-    require(require.resolve(`./plugins/${name}`)),
+  const added = names.map(
+    name => require(require.resolve(`./plugins/${name}`)) as Plugin,
   );
 
   // Jest tests snapshotSerializers in order preceding built-in serializers.
@@ -27,7 +32,7 @@ const testPath = (names: Array<string>) => {
 };
 
 it('gets plugins', () => {
-  const {getSerializers} = require('../plugins');
+  const {getSerializers} = require('../plugins') as typeof import('../plugins');
   const plugins = getSerializers();
   expect(plugins).toHaveLength(5);
 });