diff --git a/package.json b/package.json
index d8a910d73..08e2aac72 100644
--- a/package.json
+++ b/package.json
@@ -44,12 +44,12 @@
     "body-parser": "^1.18.2"
   },
   "devDependencies": {
-    "@types/chai": "4.1.2",
+    "@types/chai": "4.3.20",
     "@types/chai-http": "3.0.4",
     "@types/cucumber": "3.2.2",
     "@types/express": "4.11.1",
     "@types/node": "9.4.6",
-    "chai": "4.1.2",
+    "chai": "4.5.0",
     "chai-http": "3.0.0",
     "coveralls": "3.0.0",
     "cucumber": "3.2.1",
diff --git a/yarn.lock b/yarn.lock
index 36b14dfb6..1f7bafa9c 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -79,9 +79,10 @@
   version "4.0.10"
   resolved "https://registry.yarnpkg.com/@types/chai/-/chai-4.0.10.tgz#0eb222c7353adde8e0980bea04165d4d3b6afef3"
 
-"@types/chai@4.1.2":
-  version "4.1.2"
-  resolved "https://registry.yarnpkg.com/@types/chai/-/chai-4.1.2.tgz#f1af664769cfb50af805431c407425ed619daa21"
+"@types/chai@4.3.20":
+  version "4.3.20"
+  resolved "https://registry.yarnpkg.com/@types/chai/-/chai-4.3.20.tgz#cb291577ed342ca92600430841a00329ba05cecc"
+  integrity sha512-/pC9HAB5I/xMlc5FP77qjCnI16ChlJfW0tGa0IUcFn38VJrTV6DeZ60NU5KZBtaOZqjdpwTWohz5HU1RrhiYxQ==
 
 "@types/cucumber@3.2.2":
   version "3.2.2"
@@ -295,9 +296,10 @@ assertion-error-formatter@^2.0.1:
     pad-right "^0.2.2"
     repeat-string "^1.6.1"
 
-assertion-error@^1.0.1:
-  version "1.0.2"
-  resolved "https://registry.yarnpkg.com/assertion-error/-/assertion-error-1.0.2.tgz#13ca515d86206da0bac66e834dd397d87581094c"
+assertion-error@^1.1.0:
+  version "1.1.0"
+  resolved "https://registry.yarnpkg.com/assertion-error/-/assertion-error-1.1.0.tgz#e60b6b0e8f301bd97e5375215bda406c85118c0b"
+  integrity sha512-jgsaNduz+ndvGyFt3uSuWqvy4lCnIJiovtouQN5JZHOKCS2QuhEdbcQHFhVksz2N2U9hXJo8odG7ETyWlEeuDw==
 
 async@^1.4.0, async@^1.5.2:
   version "1.5.2"
@@ -513,16 +515,18 @@ chai-http@3.0.0:
     qs "^6.2.0"
     superagent "^2.0.0"
 
-chai@4.1.2:
-  version "4.1.2"
-  resolved "https://registry.yarnpkg.com/chai/-/chai-4.1.2.tgz#0f64584ba642f0f2ace2806279f4f06ca23ad73c"
+chai@4.5.0:
+  version "4.5.0"
+  resolved "https://registry.yarnpkg.com/chai/-/chai-4.5.0.tgz#707e49923afdd9b13a8b0b47d33d732d13812fd8"
+  integrity sha512-RITGBfijLkBddZvnn8jdqoTypxvqbOLYQkGGxXzeFjVHvudaPw0HNFD9x928/eUwYWd2dPCugVqspGALTZZQKw==
   dependencies:
-    assertion-error "^1.0.1"
-    check-error "^1.0.1"
-    deep-eql "^3.0.0"
-    get-func-name "^2.0.0"
-    pathval "^1.0.0"
-    type-detect "^4.0.0"
+    assertion-error "^1.1.0"
+    check-error "^1.0.3"
+    deep-eql "^4.1.3"
+    get-func-name "^2.0.2"
+    loupe "^2.3.6"
+    pathval "^1.1.1"
+    type-detect "^4.1.0"
 
 chalk@^1.1.3:
   version "1.1.3"
@@ -542,9 +546,12 @@ chalk@^2.3.0:
     escape-string-regexp "^1.0.5"
     supports-color "^4.0.0"
 
-check-error@^1.0.1:
-  version "1.0.2"
-  resolved "https://registry.yarnpkg.com/check-error/-/check-error-1.0.2.tgz#574d312edd88bb5dd8912e9286dd6c0aed4aac82"
+check-error@^1.0.3:
+  version "1.0.3"
+  resolved "https://registry.yarnpkg.com/check-error/-/check-error-1.0.3.tgz#a6502e4312a7ee969f646e83bb3ddd56281bd694"
+  integrity sha512-iKEoDYaRmd1mxM90a2OEfWhjsjPpYPuQ+lMYsoxB126+t8fw7ySEO48nmDg5COTjxDI65/Y2OWpeEHk3ZOe8zg==
+  dependencies:
+    get-func-name "^2.0.2"
 
 clean-stack@^1.0.0:
   version "1.3.0"
@@ -866,9 +873,10 @@ decamelize@^1.0.0, decamelize@^1.1.1, decamelize@^1.1.2:
   version "1.2.0"
   resolved "https://registry.yarnpkg.com/decamelize/-/decamelize-1.2.0.tgz#f6534d15148269b20352e7bee26f501f9a191290"
 
-deep-eql@^3.0.0:
-  version "3.0.1"
-  resolved "https://registry.yarnpkg.com/deep-eql/-/deep-eql-3.0.1.tgz#dfc9404400ad1c8fe023e7da1df1c147c4b444df"
+deep-eql@^4.1.3:
+  version "4.1.4"
+  resolved "https://registry.yarnpkg.com/deep-eql/-/deep-eql-4.1.4.tgz#d0d3912865911bb8fac5afb4e3acfa6a28dc72b7"
+  integrity sha512-SUwdGfqdKOwxCPeVYjwSyRpJ7Z+fhpwIAtmCUdZIWZ/YP5R9WAsyuSgpLVDi9bjWoN2LXHNss/dk3urXtdQxGg==
   dependencies:
     type-detect "^4.0.0"
 
@@ -1287,9 +1295,10 @@ get-caller-file@^1.0.1:
   version "1.0.2"
   resolved "https://registry.yarnpkg.com/get-caller-file/-/get-caller-file-1.0.2.tgz#f702e63127e7e231c160a80c1554acb70d5047e5"
 
-get-func-name@^2.0.0:
-  version "2.0.0"
-  resolved "https://registry.yarnpkg.com/get-func-name/-/get-func-name-2.0.0.tgz#ead774abee72e20409433a066366023dd6887a41"
+get-func-name@^2.0.1, get-func-name@^2.0.2:
+  version "2.0.2"
+  resolved "https://registry.yarnpkg.com/get-func-name/-/get-func-name-2.0.2.tgz#0d7cf20cd13fda808669ffa88f4ffc7a3943fc41"
+  integrity sha512-8vXOvuE167CtIc3OyItco7N/dpRtBbYOsPsXCz7X/PMnlGjYjSGuZJgM1Y7mmew7BKf9BqvLX2tnOVy1BBUsxQ==
 
 get-stdin@^4.0.1:
   version "4.0.1"
@@ -1873,6 +1882,13 @@ loud-rejection@^1.0.0:
     currently-unhandled "^0.4.1"
     signal-exit "^3.0.0"
 
+loupe@^2.3.6:
+  version "2.3.7"
+  resolved "https://registry.yarnpkg.com/loupe/-/loupe-2.3.7.tgz#6e69b7d4db7d3ab436328013d37d1c8c3540c697"
+  integrity sha512-zSMINGVYkdpYSOBmLi0D1Uo7JU9nVdQKrHxC8eYlV+9YKK9WePqAlL7lSlorG/U2Fw1w0hTBmaa/jrQ3UbPHtA==
+  dependencies:
+    get-func-name "^2.0.1"
+
 lower-case@^1.1.1:
   version "1.1.4"
   resolved "https://registry.yarnpkg.com/lower-case/-/lower-case-1.1.4.tgz#9a2cabd1b9e8e0ae993a4bf7d5875c39c42e8eac"
@@ -2328,9 +2344,10 @@ path-type@^3.0.0:
   dependencies:
     pify "^3.0.0"
 
-pathval@^1.0.0:
-  version "1.1.0"
-  resolved "https://registry.yarnpkg.com/pathval/-/pathval-1.1.0.tgz#b942e6d4bde653005ef6b71361def8727d0645e0"
+pathval@^1.1.1:
+  version "1.1.1"
+  resolved "https://registry.yarnpkg.com/pathval/-/pathval-1.1.1.tgz#8534e77a77ce7ac5a2512ea21e0fdb8fcf6c3d8d"
+  integrity sha512-Dp6zGqpTdETdR63lehJYPeIOqpiNBNtc7BpWSLrOje7UaIsE5aY92r/AunQA7rsXvet3lrJ3JnZX29UPTKXyKQ==
 
 performance-now@^2.1.0:
   version "2.1.0"
@@ -3038,6 +3055,11 @@ type-detect@^4.0.0:
   version "4.0.5"
   resolved "https://registry.yarnpkg.com/type-detect/-/type-detect-4.0.5.tgz#d70e5bc81db6de2a381bcaca0c6e0cbdc7635de2"
 
+type-detect@^4.1.0:
+  version "4.1.0"
+  resolved "https://registry.yarnpkg.com/type-detect/-/type-detect-4.1.0.tgz#deb2453e8f08dcae7ae98c626b13dddb0155906c"
+  integrity sha512-Acylog8/luQ8L7il+geoSxhEkazvkslg7PSNKOX59mbB9cOveP5aq9h74Y7YU8yDpJwetzQQrfIwtf4Wp4LKcw==
+
 type-is@~1.6.15:
   version "1.6.15"
   resolved "https://registry.yarnpkg.com/type-is/-/type-is-1.6.15.tgz#cab10fb4909e441c82842eafe1ad646c81804410"