fix: Add error handling for nonexistent file case with --file option

lib/cli/collect-files.js

@@ -1,12 +1,14 @@
 'use strict';
 
+const fs = require('fs');
 const path = require('path');
 const ansi = require('ansi-colors');
 const debug = require('debug')('mocha:cli:run:helpers');
 const minimatch = require('minimatch');
 const {NO_FILES_MATCH_PATTERN} = require('../errors').constants;
 const lookupFiles = require('./lookup-files');
 const {castArray} = require('../utils');
+const {createNoFilesMatchPatternError} = require('../errors');
 
 /**
  * Exports a function that collects test files from CLI parameters.
@@ -30,7 +32,7 @@ module.exports = ({
   sort,
   spec
 } = {}) => {
-  const unmatched = [];
+  const unmatchedSpecFiles = [];
   const specFiles = spec.reduce((specFiles, arg) => {
     try {
       const moreSpecFiles = castArray(lookupFiles(arg, extension, recursive))
@@ -44,14 +46,25 @@ module.exports = ({
       return [...specFiles, ...moreSpecFiles];
     } catch (err) {
       if (err.code === NO_FILES_MATCH_PATTERN) {
-        unmatched.push({message: err.message, pattern: err.pattern});
+        unmatchedSpecFiles.push({message: err.message, pattern: err.pattern});
         return specFiles;
       }
 
       throw err;
     }
   }, []);
 
+  // check that each file passed in to --file exists
+  fileArgs.forEach(file => {
+    const fileAbsolutePath = path.resolve(file);
+    if (!fs.existsSync(fileAbsolutePath)) {
+      throw createNoFilesMatchPatternError(
+        `Cannot find any files matching pattern "${fileAbsolutePath}"`,
+        fileAbsolutePath
+      );
+    }
+  });
+
   // ensure we don't sort the stuff from fileArgs; order is important!
   if (sort) {
     specFiles.sort();
@@ -67,14 +80,16 @@ module.exports = ({
   if (!files.length) {
     // give full message details when only 1 file is missing
     const noneFoundMsg =
-      unmatched.length === 1
-        ? `Error: No test files found: ${JSON.stringify(unmatched[0].pattern)}` // stringify to print escaped characters raw
+      unmatchedSpecFiles.length === 1
+        ? `Error: No test files found: ${JSON.stringify(
+            unmatchedSpecFiles[0].pattern
+          )}` // stringify to print escaped characters raw
         : 'Error: No test files found';
     console.error(ansi.red(noneFoundMsg));
     process.exit(1);
   } else {
     // print messages as a warning
-    unmatched.forEach(warning => {
+    unmatchedSpecFiles.forEach(warning => {
       console.warn(ansi.yellow(`Warning: ${warning.message}`));
     });
   }

lib/cli/run.js

@@ -15,6 +15,7 @@ const {
   createInvalidArgumentValueError,
   createMissingArgumentError
 } = require('../errors');
+const {NO_FILES_MATCH_PATTERN} = require('../errors').constants;
 
 const {
   list,
@@ -369,6 +370,14 @@ exports.handler = async function (argv) {
   try {
     await runMocha(mocha, argv);
   } catch (err) {
+    if (err.code === NO_FILES_MATCH_PATTERN) {
+      console.error(ansi.yellow(`Warning: ${err.message}`));
+      console.log(
+        'No test file found with the given pattern, exiting with code 1'
+      );
+      process.exit(1);
+    }
+
     console.error('\n' + (err.stack || `Error: ${err.message || err}`));
     process.exit(1);
   }

test/integration/options/file.spec.js

@@ -1,9 +1,11 @@
 'use strict';
 
 var path = require('path').posix;
-var helpers = require('../helpers');
-var runMochaJSON = helpers.runMochaJSON;
-var resolvePath = helpers.resolveFixturePath;
+const {
+  runMochaJSON,
+  resolveFixturePath: resolvePath,
+  runMocha
+} = require('../helpers');
 
 describe('--file', function () {
   var args = [];
@@ -64,4 +66,25 @@ describe('--file', function () {
       done();
     });
   });
+
+  it('should log a warning if a nonexistent file is specified', function (done) {
+    const nonexistentTestFileArg = 'nonexistent.test.ts';
+    runMocha(
+      nonexistentTestFileArg,
+      ['--file'],
+      function (err, res) {
+        if (err) {
+          return done(err);
+        }
+
+        expect(
+          res.output,
+          'to contain',
+          'Warning: Cannot find any files matching pattern'
+        ).and('to contain', nonexistentTestFileArg);
+        done();
+      },
+      {stdio: 'pipe'}
+    );
+  });
 });