diff --git a/package.json b/package.json
index 0d7bff0..86601a2 100644
--- a/package.json
+++ b/package.json
@@ -46,6 +46,6 @@
   "devDependencies": {
     "jshint": "2.9.5",
     "should": "13.1.2",
-    "mocha": "4.0.1"
+    "mocha": "5.2.0"
   }
 }
diff --git a/yarn.lock b/yarn.lock
index 32bbceb..e672ee6 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -148,9 +148,9 @@ brace-expansion@^1.1.7:
     balanced-match "^1.0.0"
     concat-map "0.0.1"
 
-browser-stdout@1.3.0:
-  version "1.3.0"
-  resolved "https://registry.yarnpkg.com/browser-stdout/-/browser-stdout-1.3.0.tgz#f351d32969d32fa5d7a5567154263d928ae3bd1f"
+browser-stdout@1.3.1:
+  version "1.3.1"
+  resolved "https://registry.yarnpkg.com/browser-stdout/-/browser-stdout-1.3.1.tgz#baa559ee14ced73452229bad7326467c61fabd60"
 
 browserslist@^2.4.0:
   version "2.4.0"
@@ -321,9 +321,9 @@ combined-stream@^1.0.5, combined-stream@~1.0.5:
   dependencies:
     delayed-stream "~1.0.0"
 
-commander@2.11.0:
-  version "2.11.0"
-  resolved "https://registry.yarnpkg.com/commander/-/commander-2.11.0.tgz#157152fd1e7a6c8d98a5b715cf376df928004563"
+commander@2.15.1:
+  version "2.15.1"
+  resolved "https://registry.yarnpkg.com/commander/-/commander-2.15.1.tgz#df46e867d0fc2aec66a34662b406a9ccafff5b0f"
 
 commander@2.8.x:
   version "2.8.1"
@@ -428,9 +428,9 @@ delegates@^1.0.0:
   version "1.0.0"
   resolved "https://registry.yarnpkg.com/delegates/-/delegates-1.0.0.tgz#84c6e159b81904fdca59a0ef44cd870d31250f9a"
 
-diff@3.3.1:
-  version "3.3.1"
-  resolved "https://registry.yarnpkg.com/diff/-/diff-3.3.1.tgz#aa8567a6eed03c531fc89d3f711cd0e5259dec75"
+diff@3.5.0:
+  version "3.5.0"
+  resolved "https://registry.yarnpkg.com/diff/-/diff-3.5.0.tgz#800c0dd1e0a8bfbc95835c202ad220fe317e5a12"
 
 doctypes@^1.1.0:
   version "1.1.0"
@@ -639,9 +639,9 @@ graceful-fs@^4.1.2:
   version "1.0.1"
   resolved "https://registry.yarnpkg.com/graceful-readlink/-/graceful-readlink-1.0.1.tgz#4cafad76bc62f02fa039b2f94e9a3dd3a391a725"
 
-growl@1.10.3:
-  version "1.10.3"
-  resolved "https://registry.yarnpkg.com/growl/-/growl-1.10.3.tgz#1926ba90cf3edfe2adb4927f5880bc22c66c790f"
+growl@1.10.5:
+  version "1.10.5"
+  resolved "https://registry.yarnpkg.com/growl/-/growl-1.10.5.tgz#f2735dc2283674fa67478b10181059355c369e5e"
 
 har-schema@^2.0.0:
   version "2.0.0"
@@ -676,6 +676,10 @@ has-flag@^2.0.0:
   version "2.0.0"
   resolved "https://registry.yarnpkg.com/has-flag/-/has-flag-2.0.0.tgz#e8207af1cc7b30d446cc70b734b5e8be18f88d51"
 
+has-flag@^3.0.0:
+  version "3.0.0"
+  resolved "https://registry.yarnpkg.com/has-flag/-/has-flag-3.0.0.tgz#b5d454dc2199ae225699f3467e5a07f3b955bafd"
+
 has-unicode@^2.0.0:
   version "2.0.1"
   resolved "https://registry.yarnpkg.com/has-unicode/-/has-unicode-2.0.1.tgz#e0e6fe6a28cf51138855e086d1691e771de2a8b9"
@@ -1044,7 +1048,7 @@ mime@^1.2.11:
   version "1.4.1"
   resolved "https://registry.yarnpkg.com/mime/-/mime-1.4.1.tgz#121f9ebc49e3766f311a76e1fa1c8003c4b03aa6"
 
-minimatch@^3.0.2, minimatch@^3.0.4, minimatch@~3.0.2:
+minimatch@3.0.4, minimatch@^3.0.2, minimatch@^3.0.4, minimatch@~3.0.2:
   version "3.0.4"
   resolved "https://registry.yarnpkg.com/minimatch/-/minimatch-3.0.4.tgz#5166e286457f03306064be5497e8dbb0c3d32083"
   dependencies:
@@ -1064,20 +1068,21 @@ mkdirp@0.5.1, mkdirp@0.5.x, "mkdirp@>=0.5 0", mkdirp@^0.5.0, mkdirp@^0.5.1:
   dependencies:
     minimist "0.0.8"
 
-mocha@4.0.1:
-  version "4.0.1"
-  resolved "https://registry.yarnpkg.com/mocha/-/mocha-4.0.1.tgz#0aee5a95cf69a4618820f5e51fa31717117daf1b"
+mocha@5.2.0:
+  version "5.2.0"
+  resolved "https://registry.yarnpkg.com/mocha/-/mocha-5.2.0.tgz#6d8ae508f59167f940f2b5b3c4a612ae50c90ae6"
   dependencies:
-    browser-stdout "1.3.0"
-    commander "2.11.0"
+    browser-stdout "1.3.1"
+    commander "2.15.1"
     debug "3.1.0"
-    diff "3.3.1"
+    diff "3.5.0"
     escape-string-regexp "1.0.5"
     glob "7.1.2"
-    growl "1.10.3"
+    growl "1.10.5"
     he "1.1.1"
+    minimatch "3.0.4"
     mkdirp "0.5.1"
-    supports-color "4.4.0"
+    supports-color "5.4.0"
 
 ms@2.0.0:
   version "2.0.0"
@@ -1751,16 +1756,22 @@ stylus@^0.54.5:
     sax "0.5.x"
     source-map "0.1.x"
 
-supports-color@4.4.0, supports-color@^4.0.0, supports-color@^4.4.0:
-  version "4.4.0"
-  resolved "https://registry.yarnpkg.com/supports-color/-/supports-color-4.4.0.tgz#883f7ddabc165142b2a61427f3352ded195d1a3e"
+supports-color@5.4.0:
+  version "5.4.0"
+  resolved "https://registry.yarnpkg.com/supports-color/-/supports-color-5.4.0.tgz#1c6b337402c2137605efe19f10fec390f6faab54"
   dependencies:
-    has-flag "^2.0.0"
+    has-flag "^3.0.0"
 
 supports-color@^2.0.0:
   version "2.0.0"
   resolved "https://registry.yarnpkg.com/supports-color/-/supports-color-2.0.0.tgz#535d045ce6b6363fa40117084629995e9df324c7"
 
+supports-color@^4.0.0, supports-color@^4.4.0:
+  version "4.4.0"
+  resolved "https://registry.yarnpkg.com/supports-color/-/supports-color-4.4.0.tgz#883f7ddabc165142b2a61427f3352ded195d1a3e"
+  dependencies:
+    has-flag "^2.0.0"
+
 swap-case@^1.1.0:
   version "1.1.2"
   resolved "https://registry.yarnpkg.com/swap-case/-/swap-case-1.1.2.tgz#c39203a4587385fad3c850a0bd1bcafa081974e3"