From 74a9896f6412f1c869c605c289ec951b40da962c Mon Sep 17 00:00:00 2001
From: Pascal <pascal@pascal.com>
Date: Tue, 28 May 2019 12:05:27 -0400
Subject: [PATCH] added test and fix for duplicate globals

---
 lib/mocha.js            | 8 +++++++-
 test/unit/mocha.spec.js | 8 ++++++++
 2 files changed, 15 insertions(+), 1 deletion(-)

diff --git a/lib/mocha.js b/lib/mocha.js
index aab5604448..e09aeba097 100644
--- a/lib/mocha.js
+++ b/lib/mocha.js
@@ -553,7 +553,13 @@ Mocha.prototype._growl = growl.notify;
 Mocha.prototype.globals = function(globals) {
   this.options.globals = (this.options.globals || [])
     .concat(globals)
-    .filter(Boolean);
+    .filter(Boolean)
+    .reduce(function dedupe(memo, item) {
+      if (memo.indexOf(item) < 0) {
+        memo.push(item);
+      }
+      return memo;
+    }, []);
   return this;
 };
 
diff --git a/test/unit/mocha.spec.js b/test/unit/mocha.spec.js
index 16fbbd7f82..5a4ac2e701 100644
--- a/test/unit/mocha.spec.js
+++ b/test/unit/mocha.spec.js
@@ -174,6 +174,14 @@ describe('Mocha', function() {
         expect(mocha.options.globals, 'to contain', elem, elem2);
         expect(mocha.options.globals, 'to have length', elems.length);
       });
+
+      it('should not have duplicates', function() {
+        var mocha = new Mocha({globals: [elem, elem2]});
+        var elems = [elem, elem2];
+        mocha.globals(elems);
+        expect(mocha.options.globals, 'to contain', elem, elem2);
+        expect(mocha.options.globals, 'to have length', elems.length);
+      });
     });
   });