From 750c5f81625f4f67d0d3a4602e344dac8663ee07 Mon Sep 17 00:00:00 2001
From: Juerg B <44573692+juergba@users.noreply.github.com>
Date: Fri, 17 May 2019 15:39:33 +0200
Subject: [PATCH] Fix regression/bug in "lookupFiles()" (#3905)

---
 lib/utils.js                        | 37 ++++++++++++++++-------------
 test/integration/file-utils.spec.js | 28 ++++++++++++++++++++++
 2 files changed, 49 insertions(+), 16 deletions(-)

diff --git a/lib/utils.js b/lib/utils.js
index 93005cedf2..013d3ffe0a 100644
--- a/lib/utils.js
+++ b/lib/utils.js
@@ -563,33 +563,38 @@ function isHiddenOnUnix(pathname) {
  * @public
  * @memberof Mocha.utils
  * @param {string} filepath - Base path to start searching from.
- * @param {string[]} extensions - File extensions to look for.
- * @param {boolean} recursive - Whether to recurse into subdirectories.
+ * @param {string[]} [extensions=[]] - File extensions to look for.
+ * @param {boolean} [recursive=false] - Whether to recurse into subdirectories.
  * @return {string[]} An array of paths.
  * @throws {Error} if no files match pattern.
  * @throws {TypeError} if `filepath` is directory and `extensions` not provided.
  */
 exports.lookupFiles = function lookupFiles(filepath, extensions, recursive) {
   extensions = extensions || [];
+  recursive = recursive || false;
   var files = [];
   var stat;
 
   if (!fs.existsSync(filepath)) {
-    // check all extensions
-    extensions.forEach(function(ext) {
-      if (fs.existsSync(filepath + '.' + ext)) {
-        files.push(filepath + '.' + ext);
-      }
-    });
+    var pattern;
+    if (glob.hasMagic(filepath)) {
+      // Handle glob as is without extensions
+      pattern = filepath;
+    } else {
+      // glob pattern e.g. 'filepath+(.js|.ts)'
+      var strExtensions = extensions
+        .map(function(v) {
+          return '.' + v;
+        })
+        .join('|');
+      pattern = filepath + '+(' + strExtensions + ')';
+    }
+    files = glob.sync(pattern, {nodir: true});
     if (!files.length) {
-      // Handle glob
-      files = glob.sync(filepath);
-      if (!files.length) {
-        throw createNoFilesMatchPatternError(
-          'Cannot find any files matching pattern ' + exports.dQuote(filepath),
-          filepath
-        );
-      }
+      throw createNoFilesMatchPatternError(
+        'Cannot find any files matching pattern ' + exports.dQuote(filepath),
+        filepath
+      );
     }
     return files;
   }
diff --git a/test/integration/file-utils.spec.js b/test/integration/file-utils.spec.js
index f09018871b..ae97b996e2 100644
--- a/test/integration/file-utils.spec.js
+++ b/test/integration/file-utils.spec.js
@@ -66,6 +66,34 @@ describe('file utils', function() {
       expect(res, 'to contain', nonJsFile).and('to have length', 1);
     });
 
+    it('should return only the ".js" file', function() {
+      var TsFile = tmpFile('mocha-utils.ts');
+      fs.writeFileSync(TsFile, 'yippy skippy ying yang yow');
+
+      var res = utils
+        .lookupFiles(tmpFile('mocha-utils'), ['js'], false)
+        .map(path.normalize.bind(path));
+      expect(res, 'to contain', tmpFile('mocha-utils.js')).and(
+        'to have length',
+        1
+      );
+    });
+
+    it('should return ".js" and ".ts" files', function() {
+      var TsFile = tmpFile('mocha-utils.ts');
+      fs.writeFileSync(TsFile, 'yippy skippy ying yang yow');
+
+      var res = utils
+        .lookupFiles(tmpFile('mocha-utils'), ['js', 'ts'], false)
+        .map(path.normalize.bind(path));
+      expect(
+        res,
+        'to contain',
+        tmpFile('mocha-utils.js'),
+        tmpFile('mocha-utils.ts')
+      ).and('to have length', 2);
+    });
+
     it('should require the extensions parameter when looking up a file', function() {
       var dirLookup = function() {
         return utils.lookupFiles(tmpFile('mocha-utils'), undefined, false);