Allow testMatch to take a string value

CHANGELOG.md

@@ -1,5 +1,9 @@
 ## main
 
+### Features
+
+- `[jest-config]` Allow `testMatch` to take a string value
+
 ### Fixes
 
 - `[expect]` Fix `bigint` error ([#15702](https://github.com/jestjs/jest/pull/15702))

packages/jest-config/src/ValidConfig.ts

@@ -156,10 +156,13 @@ export const initialOptions: Config.InitialOptions = {
   },
   testFailureExitCode: 1,
   testLocationInResults: false,
-  testMatch: [
-    '**/__tests__/**/*.?([mc])[jt]s?(x)',
-    '**/?(*.)+(spec|test).?([mc])[jt]s?(x)',
-  ],
+  testMatch: multipleValidOptions(
+    '**/__tests__/**/?(*.)+(spec|test).?([mc])[jt]s?(x)',
+    [
+      '**/__tests__/**/*.?([mc])[jt]s?(x)',
+      '**/?(*.)+(spec|test).?([mc])[jt]s?(x)',
+    ],
+  ),
   testNamePattern: 'test signature',
   testPathIgnorePatterns: [NODE_MODULES_REGEXP],
   testRegex: multipleValidOptions(

packages/jest-config/src/__tests__/normalize.test.ts

@@ -954,7 +954,7 @@ describe('testMatch', () => {
     ).rejects.toThrowErrorMatchingSnapshot();
   });
 
-  it('normalizes testMatch', async () => {
+  it('normalizes testMatch root directory', async () => {
     const {options} = await normalize(
       {
         rootDir: '/root',
@@ -965,6 +965,18 @@ describe('testMatch', () => {
 
     expect(options.testMatch).toEqual(['/root/**/*.js']);
   });
+
+  it('normalizes testMatch to array', async () => {
+    const {options} = await normalize(
+      {
+        rootDir: '/root',
+        testMatch: '**/*.js',
+      },
+      {} as Config.Argv,
+    );
+
+    expect(options.testMatch).toEqual(['**/*.js']);
+  });
 });
 
 describe('moduleDirectories', () => {

packages/jest-config/src/normalize.ts

@@ -769,9 +769,12 @@
       case 'moduleDirectories':
       case 'testMatch':
         {
+          const option = oldOptions[key];
+          const rawValue =
+            Array.isArray(option) || option == null ? option : [option];
           const replacedRootDirTags = _replaceRootDirTags(
             escapeGlobCharacters(options.rootDir),
-            oldOptions[key],
+            rawValue,
           );
 
           if (replacedRootDirTags) {

packages/jest-schemas/src/raw-types.ts

@@ -323,7 +323,7 @@ export const InitialOptions = Type.Partial(
     testEnvironmentOptions: Type.Record(Type.String(), Type.Unknown()),
     testFailureExitCode: Type.Integer(),
     testLocationInResults: Type.Boolean(),
-    testMatch: Type.Array(Type.String()),
+    testMatch: Type.Union([Type.String(), Type.Array(Type.String())]),
     testNamePattern: Type.String(),
     testPathIgnorePatterns: Type.Array(Type.String()),
     testRegex: Type.Union([Type.String(), Type.Array(Type.String())]),

packages/jest-types/src/Config.ts

@@ -470,7 +470,7 @@ export type Argv = Arguments<
     testEnvironment: string;
     testEnvironmentOptions: string;
     testFailureExitCode: string | null | undefined;
-    testMatch: Array<string>;
+    testMatch: string | Array<string>;
     testNamePattern: string;
     testPathIgnorePatterns: Array<string>;
     testPathPatterns: Array<string>;

website/versioned_docs/version-30.0/Configuration.md

@@ -2045,7 +2045,7 @@ This does not change the exit code in the case of Jest errors (e.g. invalid conf
 
 :::
 
-### `testMatch` \[array<string>]
+### `testMatch` \[string | array<string>]
 
 (default: `[ "**/__tests__/**/*.?([mc])[jt]s?(x)", "**/?(*.)+(spec|test).?([mc])[jt]s?(x)" ]`)
 
@@ -2073,7 +2073,7 @@ These pattern strings match against the full path. Use the `<rootDir>` string to
 
 Default: `(/__tests__/.*|(\\.|/)(test|spec))\\.[mc]?[jt]sx?$`
 
-The pattern or patterns Jest uses to detect test files. By default it looks for `.js`, `.jsx`, `.ts` and `.tsx` files inside of `__tests__` folders, as well as any files with a suffix of `.test` or `.spec` (e.g. `Component.test.js` or `Component.spec.js`). It will also find files called `test.js` or `spec.js`. See also [`testMatch` [array&lt;string&gt;]](#testmatch-arraystring), but note that you cannot specify both options.
+The pattern or patterns Jest uses to detect test files. By default it looks for `.js`, `.jsx`, `.ts` and `.tsx` files inside of `__tests__` folders, as well as any files with a suffix of `.test` or `.spec` (e.g. `Component.test.js` or `Component.spec.js`). It will also find files called `test.js` or `spec.js`. See also [`testMatch` [string | array&lt;string&gt;]](#testmatch-arraystring), but note that you cannot specify both options.
 
 The following is a visualization of the default regex: