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

lib/cli/collect-files.js

@@ -7,6 +7,7 @@ const minimatch = require('minimatch');
 const {NO_FILES_MATCH_PATTERN} = require('../errors').constants;
 const lookupFiles = require('./lookup-files');
 const {castArray} = require('../utils');
+const symbols = require('log-symbols');
 
 /**
  * Exports a function that collects test files from CLI parameters.
@@ -52,6 +53,22 @@ module.exports = ({
     }
   }, []);
 
+  // check that each file passed in to --file exists
+  fileArgs.forEach(file => {
+    const fileAbsolutePath = path.resolve(file);
+    try {
+      require.resolve(fileAbsolutePath);
+    } catch (err) {
+      // this error doesn't bubble up to the middleware like how
+      // --require handles it so we log a warning here and exit
+      const warningMessage = ansi.yellow(
+        `${symbols.warning} Warning: Cannot find test file "${file}" at the path "${fileAbsolutePath}"`
+      );
+      console.warn(`${warningMessage}\n`);
+      process.exit(1);
+    }
+  });
+
   // ensure we don't sort the stuff from fileArgs; order is important!
   if (sort) {
     specFiles.sort();

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 +66,24 @@ 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 test file').and(
+          'to contain',
+          nonexistentTestFileArg
+        );
+        done();
+      },
+      {stdio: 'pipe'}
+    );
+  });
 });