ensure --debug becomes --inspect; closes #3697

- add some handiness to the integration test helpers
- update docstrings in integration test helpers

bin/mocha

@@ -39,8 +39,9 @@ Object.keys(opts).forEach(opt => {
   }
 });
 
-// allow --debug to invoke --inspect on Node.js v8 or newer  nodeOpts.inspect = childOpts.debug;
+// allow --debug to invoke --inspect on Node.js v8 or newer
 if (childOpts.debug) {
+  nodeOpts.inspect = childOpts.debug;
   childOpts.timeout = false;
   delete childOpts.debug;
   debug('--debug -> --inspect');

test/assertions.js

@@ -59,9 +59,9 @@ exports.mixinMochaAssertions = function(expect) {
       }
     )
     .addAssertion(
-      '<RawRunResult|JSONRunResult> [not] to have completed with [exit] code <number>',
+      '<RawResult|RawRunResult|JSONRunResult> [not] to have [completed with] [exit] code <number>',
       function(expect, result, code) {
-        expect(result.code, '[not] to be', code);
+        expect(result, '[not] to have property', 'code', code);
       }
     )
     .addAssertion(
@@ -290,17 +290,10 @@ exports.mixinMochaAssertions = function(expect) {
         });
       }
     )
-    .addAssertion('<RawRunResult> [not] to contain output <any>', function(
-      expect,
-      result,
-      output
-    ) {
-      expect(result.output, '[not] to satisfy', output);
-    })
     .addAssertion(
-      '<RawRunResult|JSONRunResult> to have [exit] code <number>',
-      function(expect, result, code) {
-        expect(result.code, 'to be', code);
+      '<RawResult|RawRunResult> [not] to contain [output] <any>',
+      function(expect, result, output) {
+        expect(result.output, '[not] to satisfy', output);
       }
     );
 };

test/integration/fixtures/__default__.fixture.js

@@ -0,0 +1,9 @@
+// this generic fixture does nothing special and will be used if no fixture is supplied
+
+'use strict';
+
+describe('a suite', function() {
+  it('should succeed', function(done) {
+    done();
+  });
+});

test/integration/helpers.js

@@ -5,7 +5,12 @@ var spawn = require('cross-spawn').spawn;
 var path = require('path');
 var baseReporter = require('../../lib/reporters/base');
 
+var DEFAULT_FIXTURE = resolveFixturePath('__default__');
+var MOCHA_EXECUTABLE = require.resolve('../../bin/mocha');
+var _MOCHA_EXECUTABLE = require.resolve('../../bin/_mocha');
+
 module.exports = {
+  DEFAULT_FIXTURE: DEFAULT_FIXTURE,
   /**
    * Invokes the mocha binary for the given fixture with color output disabled.
    * Accepts an array of additional command line args to pass. The callback is
@@ -177,20 +182,56 @@ function toJSONRunResult(result) {
   return result;
 }
 
-function invokeMocha(args, fn, opts) {
-  args = [path.join(__dirname, '..', '..', 'bin', 'mocha')].concat(args);
+/**
+ * Creates arguments loading a default fixture if none provided
+ *
+ * @param {string[]|*} [args] - Arguments to `spawn`
+ * @returns string[]
+ */
+function defaultArgs(args) {
+  return !args || !args.length ? ['--file', DEFAULT_FIXTURE] : args;
+}
 
-  return _spawnMochaWithListeners(args, fn, opts);
+function invokeMocha(args, fn, opts) {
+  if (typeof args === 'function') {
+    opts = fn;
+    fn = args;
+    args = [];
+  }
+  return _spawnMochaWithListeners(
+    defaultArgs([MOCHA_EXECUTABLE].concat(args)),
+    fn,
+    opts
+  );
 }
 
 function invokeSubMocha(args, fn, opts) {
-  args = [path.join(__dirname, '..', '..', 'bin', '_mocha')].concat(args);
-
-  return _spawnMochaWithListeners(args, fn, opts);
+  if (typeof args === 'function') {
+    opts = fn;
+    fn = args;
+    args = [];
+  }
+  return _spawnMochaWithListeners(
+    defaultArgs([_MOCHA_EXECUTABLE].concat(args)),
+    fn,
+    opts
+  );
 }
 
+/**
+ * Spawns Mocha in a subprocess and returns an object containing its output and exit code
+ *
+ * @param {string[]} args - Path to executable and arguments
+ * @param {Function} fn - Callback
+ * @param {Object|string} [opts] - Options to `cross-spawn`, or 'pipe' for shortcut to `{stdio: pipe}`
+ * @returns {ChildProcess}
+ * @private
+ */
 function _spawnMochaWithListeners(args, fn, opts) {
   var output = '';
+  if (opts === 'pipe') {
+    opts = {stdio: 'pipe'};
+  }
   opts = Object.assign(
     {
       cwd: process.cwd(),

test/integration/options/debug.spec.js

@@ -0,0 +1,32 @@
+'use strict';
+
+var helpers = require('../helpers');
+var invokeMocha = helpers.invokeMocha;
+var DEFAULT_FIXTURE = helpers.DEFAULT_FIXTURE;
+
+describe('--debug', function() {
+  describe('Node.js v8+', function() {
+    before(function() {
+      if (process.version.substring(0, 2) === 'v6') {
+        this.skip();
+      }
+    });
+
+    it('should invoke --inspect', function(done) {
+      invokeMocha(
+        ['--debug', '--file', DEFAULT_FIXTURE],
+        function(err, res) {
+          if (err) {
+            return done(err);
+          }
+          expect(res, 'to have passed').and(
+            'to contain output',
+            /Debugger listening/i
+          );
+          done();
+        },
+        {stdio: 'pipe'}
+      );
+    });
+  });
+});