Refactor statistics (#3458)

* collect stats

lib/reporters/base.js

@@ -270,9 +270,7 @@ exports.list = function(failures) {
  * Initialize a new `Base` reporter.
  *
  * All other reporters generally
- * inherit from this reporter, providing
- * stats such as test duration, number
- * of tests passed / failed etc.
+ * inherit from this reporter.
  *
  * @memberof Mocha.reporters
  * @public
@@ -281,68 +279,31 @@ exports.list = function(failures) {
  */
 
 function Base(runner) {
-  var stats = (this.stats = {
-    suites: 0,
-    tests: 0,
-    passes: 0,
-    pending: 0,
-    failures: 0
-  });
   var failures = (this.failures = []);
 
   if (!runner) {
-    return;
+    throw new TypeError('Missing runner argument');
   }
+  this.stats = runner.stats; // assigned so Reporters keep a closer reference
   this.runner = runner;
 
-  runner.stats = stats;
-
-  runner.on('start', function() {
-    stats.start = new Date();
-  });
-
-  runner.on('suite', function(suite) {
-    stats.suites = stats.suites || 0;
-    suite.root || stats.suites++;
-  });
-
-  runner.on('test end', function() {
-    stats.tests = stats.tests || 0;
-    stats.tests++;
-  });
-
   runner.on('pass', function(test) {
-    stats.passes = stats.passes || 0;
-
     if (test.duration > test.slow()) {
       test.speed = 'slow';
     } else if (test.duration > test.slow() / 2) {
       test.speed = 'medium';
     } else {
       test.speed = 'fast';
     }
-
-    stats.passes++;
   });
 
   runner.on('fail', function(test, err) {
-    stats.failures = stats.failures || 0;
-    stats.failures++;
     if (showDiff(err)) {
       stringifyDiffObjs(err);
     }
     test.err = err;
     failures.push(test);
   });
-
-  runner.once('end', function() {
-    stats.end = new Date();
-    stats.duration = stats.end - stats.start;
-  });
-
-  runner.on('pending', function() {
-    stats.pending++;
-  });
 }
 
 /**

lib/runner.js

@@ -12,6 +12,7 @@ var utils = require('./utils');
 var inherits = utils.inherits;
 var debug = require('debug')('mocha:runner');
 var Runnable = require('./runnable');
+var createStatsCollector = require('./stats-collector');
 var stackFilter = utils.stackTraceFilter();
 var stringify = utils.stringify;
 var type = utils.type;
@@ -80,6 +81,7 @@ function Runner(suite, delay) {
   this._defaultGrep = /.*/;
   this.grep(this._defaultGrep);
   this.globals(this.globalProps().concat(extraGlobals()));
+  createStatsCollector(this);
 }
 
 /**

lib/stats-collector.js

@@ -0,0 +1,70 @@
+'use strict';
+
+/**
+ * Test statistics collector.
+ *
+ * @typedef {Object} StatsCollector
+ * @property {number} suites - integer count of suites run.
+ * @property {number} tests - integer count of tests run.
+ * @property {number} passes - integer count of passing tests.
+ * @property {number} pending - integer count of pending tests.
+ * @property {number} failures - integer count of failed tests.
+ * @property {Date} start - time when testing began.
+ * @property {Date} end - time when testing concluded.
+ * @property {number} duration - number of msecs that testing took.
+ */
+
+/**
+ * Provides stats such as test duration,
+ * number of tests passed / failed etc.
+ *
+ * @public
+ * @memberof Mocha
+ * @param {Runner} runner
+ */
+function createStatsCollector(runner) {
+  var stats = {
+    suites: 0,
+    tests: 0,
+    passes: 0,
+    pending: 0,
+    failures: 0
+  };
+
+  if (!runner) {
+    throw new TypeError('Missing runner argument');
+  }
+
+  runner.stats = stats;
+
+  runner.once('start', function() {
+    stats.start = new Date();
+  });
+
+  runner.on('suite', function(suite) {
+    suite.root || stats.suites++;
+  });
+
+  runner.on('pass', function() {
+    stats.passes++;
+  });
+
+  runner.on('fail', function() {
+    stats.failures++;
+  });
+
+  runner.on('pending', function() {
+    stats.pending++;
+  });
+
+  runner.on('test end', function() {
+    stats.tests++;
+  });
+
+  runner.once('end', function() {
+    stats.end = new Date();
+    stats.duration = stats.end - stats.start;
+  });
+}
+
+module.exports = createStatsCollector;

test/reporters/helpers.js

@@ -8,6 +8,8 @@
   scope of this function for the tests to run properly.
 */
 
+var createStatsCollector = require('../../lib/stats-collector');
+
 function createMockRunner(runStr, ifStr1, ifStr2, ifStr3, arg1, arg2) {
   var runnerFunction = createRunnerFunction(
     runStr,
@@ -17,10 +19,12 @@ function createMockRunner(runStr, ifStr1, ifStr2, ifStr3, arg1, arg2) {
     arg1,
     arg2
   );
-  return {
+  var mockRunner = {
     on: runnerFunction,
     once: runnerFunction
   };
+  createStatsCollector(mockRunner);
+  return mockRunner;
 }
 
 function createRunnerFunction(runStr, ifStr1, ifStr2, ifStr3, arg1, arg2) {

test/reporters/list.spec.js

@@ -21,6 +21,7 @@ describe('List reporter', function() {
     duration: expectedDuration,
     slow: function() {}
   };
+
   beforeEach(function() {
     useColors = Base.useColors;
     Base.useColors = false;
@@ -126,7 +127,11 @@ describe('List reporter', function() {
       test = {};
       runner = createMockRunner('fail', 'fail', null, null, test);
       runner.on = runner.once = function(event, callback) {
-        if (!checked && event === 'fail') {
+        if (
+          !checked &&
+          event === 'fail' &&
+          callback.toString().includes('stringifyDiffObjs') // target correct fail event callback
+        ) {
           err = new Error('fake failure object with actual/expected');
           err.actual = actual;
           err.expected = expected;

test/reporters/xunit.spec.js

@@ -4,12 +4,14 @@ var fs = require('fs');
 var mkdirp = require('mkdirp');
 var path = require('path');
 var assert = require('assert');
+var createStatsCollector = require('../../lib/stats-collector');
 var reporters = require('../../').reporters;
 var XUnit = reporters.XUnit;
 
 describe('XUnit reporter', function() {
   var stdout;
   var stdoutWrite;
+  // the runner parameter of the reporter
   var runner;
 
   var callbackArgument = null;
@@ -26,6 +28,7 @@ describe('XUnit reporter', function() {
   beforeEach(function() {
     stdout = [];
     runner = {on: function() {}, once: function() {}};
+    createStatsCollector(runner);
   });
 
   describe('if reporter options output is given', function() {
@@ -322,8 +325,6 @@ describe('XUnit reporter', function() {
   describe('custom suite name', function() {
     // capture the events that the reporter subscribes to
     var events;
-    // the runner parameter of the reporter
-    var runner;
     // capture output lines (will contain the resulting XML of the xunit reporter)
     var lines;
     // the file stream into which the xunit reporter will write into
@@ -332,13 +333,10 @@ describe('XUnit reporter', function() {
     beforeEach(function() {
       events = {};
 
-      runner = {
-        on: function(eventName, eventHandler) {
-          // capture the event handler
-          events[eventName] = eventHandler;
-        }
+      runner.on = runner.once = function(eventName, eventHandler) {
+        // capture the event handler
+        events[eventName] = eventHandler;
       };
-      runner.once = runner.on;
 
       lines = [];
       fileStream = {