Factor out toString() call

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

@@ -1631,13 +1631,6 @@ describe('testPathPattern', () => {
         expect(options.testPathPattern).toBe('a/b|c/d');
       });
 
-      it('coerces all patterns to strings', async () => {
-        const argv = {[opt.property]: [1]} as Config.Argv;
-        const {options} = await normalize(initialOptions, argv);
-
-        expect(options.testPathPattern).toBe('1');
-      });
-
       describe('posix', () => {
         it('should not escape the pattern', async () => {
           const argv = {
@@ -1694,6 +1687,13 @@ describe('testPathPattern', () => {
     });
   }
 
+  it('coerces <regexForTestFiles> patterns to strings', async () => {
+    const argv = {_: [1]} as Config.Argv;
+    const {options} = await normalize(initialOptions, argv);
+
+    expect(options.testPathPattern).toBe('1');
+  });
+
   it('joins multiple --testPathPatterns and <regexForTestFiles>', async () => {
     const {options} = await normalize(initialOptions, {
       _: ['a', 'b'],

packages/jest-config/src/normalize.ts

@@ -395,20 +395,14 @@ const buildTestPathPattern = (argv: Config.Argv): string => {
   const patterns = [];
 
   if (argv._) {
-    patterns.push(...argv._);
+    patterns.push(...argv._.map(x => x.toString()));
   }
   if (argv.testPathPattern) {
     patterns.push(...argv.testPathPattern);
   }
 
-  const replacePosixSep = (pattern: string | number) => {
-    // yargs coerces positional args into numbers
-    const patternAsString = pattern.toString();
-    if (path.sep === '/') {
-      return patternAsString;
-    }
-    return patternAsString.replace(/\//g, '\\\\');
-  };
+  const replacePosixSep = (pattern: string) =>
+    path.sep === '/' ? pattern : pattern.replace(/\//g, '\\\\');
 
   const testPathPattern = patterns.map(replacePosixSep).join('|');
   if (validatePattern(testPathPattern)) {