diff --git a/package.json b/package.json
index 44426c8..93ec6cb 100644
--- a/package.json
+++ b/package.json
@@ -23,7 +23,7 @@
     "cpy-cli": "^2.0.0",
     "cross-env": "^5.2.0",
     "flow-bin": "^0.89.0",
-    "mocha": "^6.2.2",
+    "mocha": "^7.1.2",
     "rollup": "^1.32.0",
     "rollup-plugin-node-resolve": "^4.2.4",
     "rollup-plugin-typescript2": "^0.18.1",
diff --git a/yarn.lock b/yarn.lock
index 69c74d0..89a009f 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -161,6 +161,14 @@ ansi-styles@^3.2.0, ansi-styles@^3.2.1:
   dependencies:
     color-convert "^1.9.0"
 
+anymatch@~3.1.1:
+  version "3.1.1"
+  resolved "https://registry.yarnpkg.com/anymatch/-/anymatch-3.1.1.tgz#c55ecf02185e2469259399310c173ce31233b142"
+  integrity sha512-mM8522psRCqzV+6LhomX5wgp25YVibjh8Wj23I5RPkPppSVSjyKD2A2mBJmWGa+KN7f2D6LNh9jkBCeyLktzjg==
+  dependencies:
+    normalize-path "^3.0.0"
+    picomatch "^2.0.4"
+
 arg@^4.1.0:
   version "4.1.1"
   resolved "https://registry.yarnpkg.com/arg/-/arg-4.1.1.tgz#485f8e7c390ce4c5f78257dbea80d4be11feda4c"
@@ -256,6 +264,11 @@ base@^0.11.1:
     mixin-deep "^1.2.0"
     pascalcase "^0.1.1"
 
+binary-extensions@^2.0.0:
+  version "2.0.0"
+  resolved "https://registry.yarnpkg.com/binary-extensions/-/binary-extensions-2.0.0.tgz#23c0df14f6a88077f5f986c0d167ec03c3d5537c"
+  integrity sha512-Phlt0plgpIIBOGTT/ehfFnbNlfsDEiqmzE2KRXoX1bLIlir4X/MR+zSyBEkL05ffWgnRSf/DXv+WrUAVr93/ow==
+
 brace-expansion@^1.1.7:
   version "1.1.11"
   resolved "https://registry.yarnpkg.com/brace-expansion/-/brace-expansion-1.1.11.tgz#3c7fcbf529d87226f3d2f52b966ff5271eb441dd"
@@ -287,6 +300,13 @@ braces@^2.3.1:
     split-string "^3.0.2"
     to-regex "^3.0.1"
 
+braces@~3.0.2:
+  version "3.0.2"
+  resolved "https://registry.yarnpkg.com/braces/-/braces-3.0.2.tgz#3454e1a462ee8d599e236df336cd9ea4f8afe107"
+  integrity sha512-b8um+L1RzM3WDSzvhm6gIz1yfTbBt6YTlcEKAvsmqCZZFw46z626lVj9j1yEPW33H5H+lBQpZMP1k8l+78Ha0A==
+  dependencies:
+    fill-range "^7.0.1"
+
 browser-stdout@1.3.1:
   version "1.3.1"
   resolved "https://registry.yarnpkg.com/browser-stdout/-/browser-stdout-1.3.1.tgz#baa559ee14ced73452229bad7326467c61fabd60"
@@ -341,7 +361,7 @@ camelcase@^5.0.0:
   resolved "https://registry.yarnpkg.com/camelcase/-/camelcase-5.3.1.tgz#e3c9b31569e106811df242f715725a1f4c494320"
   integrity sha512-L28STB170nwWS63UjtlEOE3dldQApaJXZkOI1uMFfzf3rRuPegHaHesyee+YxQ+W6SvRDQV6UrdOdRiR153wJg==
 
-chalk@^2.0.1:
+chalk@^2.4.2:
   version "2.4.2"
   resolved "https://registry.yarnpkg.com/chalk/-/chalk-2.4.2.tgz#cd42541677a54333cf541a49108c1432b44c9424"
   integrity sha512-Mti+f9lpJNcwF4tWV8/OrTTtF1gZi+f8FqlyAdouralcFWFQWF2+NgCHShjkCb+IFBLq9buZwE1xckQU4peSuQ==
@@ -350,6 +370,21 @@ chalk@^2.0.1:
     escape-string-regexp "^1.0.5"
     supports-color "^5.3.0"
 
+chokidar@3.3.0:
+  version "3.3.0"
+  resolved "https://registry.yarnpkg.com/chokidar/-/chokidar-3.3.0.tgz#12c0714668c55800f659e262d4962a97faf554a6"
+  integrity sha512-dGmKLDdT3Gdl7fBUe8XK+gAtGmzy5Fn0XkkWQuYxGIgWVPPse2CxFA5mtrlD0TOHaHjEUqkWNyP1XdHoJES/4A==
+  dependencies:
+    anymatch "~3.1.1"
+    braces "~3.0.2"
+    glob-parent "~5.1.0"
+    is-binary-path "~2.1.0"
+    is-glob "~4.0.1"
+    normalize-path "~3.0.0"
+    readdirp "~3.2.0"
+  optionalDependencies:
+    fsevents "~2.1.1"
+
 class-utils@^0.3.5:
   version "0.3.6"
   resolved "https://registry.yarnpkg.com/class-utils/-/class-utils-0.3.6.tgz#f93369ae8b9a7ce02fd41faad0ca83033190c463"
@@ -678,6 +713,13 @@ fill-range@^4.0.0:
     repeat-string "^1.6.1"
     to-regex-range "^2.1.0"
 
+fill-range@^7.0.1:
+  version "7.0.1"
+  resolved "https://registry.yarnpkg.com/fill-range/-/fill-range-7.0.1.tgz#1919a6a7c75fe38b2c7c77e5198535da9acdda40"
+  integrity sha512-qOo9F+dMUmC2Lcb4BbVvnKJxTPjCm+RRpe4gDuGrzkL7mEVl/djYSu2OdQ2Pa302N4oqkSg9ir6jaLWJ2USVpQ==
+  dependencies:
+    to-regex-range "^5.0.1"
+
 find-up@3.0.0, find-up@^3.0.0:
   version "3.0.0"
   resolved "https://registry.yarnpkg.com/find-up/-/find-up-3.0.0.tgz#49169f1d7993430646da61ecc5ae355c21c97b73"
@@ -734,6 +776,11 @@ fs.realpath@^1.0.0:
   version "1.0.0"
   resolved "https://registry.yarnpkg.com/fs.realpath/-/fs.realpath-1.0.0.tgz#1504ad2523158caa40db4a2787cb01411994ea4f"
 
+fsevents@~2.1.1:
+  version "2.1.3"
+  resolved "https://registry.yarnpkg.com/fsevents/-/fsevents-2.1.3.tgz#fb738703ae8d2f9fe900c33836ddebee8b97f23e"
+  integrity sha512-Auw9a4AxqWpa9GUfj370BMPzzyncfBABW8Mab7BGWBYDj4Isgq+cDKtx0i6u9jcX9pQDnswsaaOTgTmA5pEjuQ==
+
 function-bind@^1.1.1:
   version "1.1.1"
   resolved "https://registry.yarnpkg.com/function-bind/-/function-bind-1.1.1.tgz#a56899d3ea3c9bab874bb9773b7c5ede92f4895d"
@@ -770,6 +817,13 @@ glob-parent@^3.1.0:
     is-glob "^3.1.0"
     path-dirname "^1.0.0"
 
+glob-parent@~5.1.0:
+  version "5.1.1"
+  resolved "https://registry.yarnpkg.com/glob-parent/-/glob-parent-5.1.1.tgz#b6c1ef417c4e5663ea498f1c45afac6916bbc229"
+  integrity sha512-FnI+VGOpnlGHWZxthPGR+QhR78fuiK0sNLkHQv+bL9fQi57lNNdquIbna/WrfROrolq8GK5Ek6BiMwqL/voRYQ==
+  dependencies:
+    is-glob "^4.0.1"
+
 glob-to-regexp@^0.3.0:
   version "0.3.0"
   resolved "https://registry.yarnpkg.com/glob-to-regexp/-/glob-to-regexp-0.3.0.tgz#8c5a1494d2066c570cc3bfe4496175acc4d502ab"
@@ -920,6 +974,13 @@ is-arrayish@^0.2.1:
   resolved "https://registry.yarnpkg.com/is-arrayish/-/is-arrayish-0.2.1.tgz#77c99840527aa8ecb1a8ba697b80645a7a926a9d"
   integrity sha1-d8mYQFJ6qOyxqLppe4BkWnqSap0=
 
+is-binary-path@~2.1.0:
+  version "2.1.0"
+  resolved "https://registry.yarnpkg.com/is-binary-path/-/is-binary-path-2.1.0.tgz#ea1f7f3b80f064236e83470f86c09c254fb45b09"
+  integrity sha512-ZMERYes6pDydyuGidse7OsHxtbI7WVeUEozgR/g7rd0xUimYNlvZRE/K2MgZTjWy725IfelLeVcEM97mmtRGXw==
+  dependencies:
+    binary-extensions "^2.0.0"
+
 is-buffer@^1.1.5:
   version "1.1.6"
   resolved "https://registry.yarnpkg.com/is-buffer/-/is-buffer-1.1.6.tgz#efaa2ea9daa0d7ab2ea13a97b2b8ad51fefbe8be"
@@ -1019,7 +1080,7 @@ is-glob@^3.1.0:
   dependencies:
     is-extglob "^2.1.0"
 
-is-glob@^4.0.0:
+is-glob@^4.0.0, is-glob@^4.0.1, is-glob@~4.0.1:
   version "4.0.1"
   resolved "https://registry.yarnpkg.com/is-glob/-/is-glob-4.0.1.tgz#7567dbe9f2f5e2467bc77ab83c4a29482407a5dc"
   integrity sha512-5G0tKtBTFImOqDnLB2hG6Bp2qcKEFduo4tZu9MT/H6NQv/ghhy30o55ufafxJ/LdH79LLs2Kfrn85TLKyA7BUg==
@@ -1047,6 +1108,11 @@ is-number@^4.0.0:
   version "4.0.0"
   resolved "https://registry.yarnpkg.com/is-number/-/is-number-4.0.0.tgz#0026e37f5454d73e356dfe6564699867c6a7f0ff"
 
+is-number@^7.0.0:
+  version "7.0.0"
+  resolved "https://registry.yarnpkg.com/is-number/-/is-number-7.0.0.tgz#7535345b896734d5f80c4d06c50955527a14f12b"
+  integrity sha512-41Cifkg6e8TylSpdtTpeLVMqvSBEVzTttHvERD741+pnZ8ANv0004MRL43QKPDlK9cGvNp6NZWZUBlbGXYxxng==
+
 is-plain-obj@^1.1.0:
   version "1.1.0"
   resolved "https://registry.yarnpkg.com/is-plain-obj/-/is-plain-obj-1.1.0.tgz#71a50c8429dfca773c92a390a4a03b39fcd51d3e"
@@ -1192,12 +1258,12 @@ lodash@^4.17.15:
   resolved "https://registry.yarnpkg.com/lodash/-/lodash-4.17.15.tgz#b447f6670a0455bbfeedd11392eff330ea097548"
   integrity sha512-8xOcRHvCjnocdS5cpwXQXVzmmh5e5+saE2QGoeQmbKmRS6J3VQppPOIt0MnmE+4xlZoumy0GPG0D0MVIQbNA1A==
 
-log-symbols@2.2.0:
-  version "2.2.0"
-  resolved "https://registry.yarnpkg.com/log-symbols/-/log-symbols-2.2.0.tgz#5740e1c5d6f0dfda4ad9323b5332107ef6b4c40a"
-  integrity sha512-VeIAFslyIerEJLXHziedo2basKbMKtTw3vfn5IzG0XTjhAVEJyNHnL2p7vc+wBDSdQuUpNw3M2u6xb9QsAY5Eg==
+log-symbols@3.0.0:
+  version "3.0.0"
+  resolved "https://registry.yarnpkg.com/log-symbols/-/log-symbols-3.0.0.tgz#f3a08516a5dea893336a7dee14d18a1cfdab77c4"
+  integrity sha512-dSkNGuI7iG3mfvDzUuYZyvk5dD9ocYCYzNU6CYDE6+Xqd+gwme6Z00NS3dUh8mq/73HaEtT7m6W+yUPtU6BZnQ==
   dependencies:
-    chalk "^2.0.1"
+    chalk "^2.4.2"
 
 lolex@^4.1.0, lolex@^4.2.0:
   version "4.2.0"
@@ -1322,10 +1388,10 @@ minimist-options@^3.0.1:
     arrify "^1.0.1"
     is-plain-obj "^1.1.0"
 
-minimist@0.0.8:
-  version "0.0.8"
-  resolved "https://registry.yarnpkg.com/minimist/-/minimist-0.0.8.tgz#857fcabfc3397d2625b8228262e86aa7a011b05d"
-  integrity sha1-hX/Kv8M5fSYluCKCYuhqp6ARsF0=
+minimist@^1.2.5:
+  version "1.2.5"
+  resolved "https://registry.yarnpkg.com/minimist/-/minimist-1.2.5.tgz#67d66014b66a6a8aaa0c083c5fd58df4e4e97602"
+  integrity sha512-FM9nNUYrRBAELZQT3xeZQ7fmMOBg6nWNmJKTcgsJeaLstP/UODVpGsr5OhXhhXg6f+qtJ8uiZ+PUxkDWcgIXLw==
 
 mixin-deep@^1.2.0:
   version "1.3.2"
@@ -1335,20 +1401,21 @@ mixin-deep@^1.2.0:
     for-in "^1.0.2"
     is-extendable "^1.0.1"
 
-mkdirp@0.5.1:
-  version "0.5.1"
-  resolved "https://registry.yarnpkg.com/mkdirp/-/mkdirp-0.5.1.tgz#30057438eac6cf7f8c4767f38648d6697d75c903"
-  integrity sha1-MAV0OOrGz3+MR2fzhkjWaX11yQM=
+mkdirp@0.5.5:
+  version "0.5.5"
+  resolved "https://registry.yarnpkg.com/mkdirp/-/mkdirp-0.5.5.tgz#d91cefd62d1436ca0f41620e251288d420099def"
+  integrity sha512-NKmAlESf6jMGym1++R0Ra7wvhV+wFW63FaSOFPwRahvea0gMUcGUhVeAg/0BC0wiv9ih5NYPB1Wn1UEI1/L+xQ==
   dependencies:
-    minimist "0.0.8"
+    minimist "^1.2.5"
 
-mocha@^6.2.2:
-  version "6.2.2"
-  resolved "https://registry.yarnpkg.com/mocha/-/mocha-6.2.2.tgz#5d8987e28940caf8957a7d7664b910dc5b2fea20"
-  integrity sha512-FgDS9Re79yU1xz5d+C4rv1G7QagNGHZ+iXF81hO8zY35YZZcLEsJVfFolfsqKFWunATEvNzMK0r/CwWd/szO9A==
+mocha@^7.1.2:
+  version "7.1.2"
+  resolved "https://registry.yarnpkg.com/mocha/-/mocha-7.1.2.tgz#8e40d198acf91a52ace122cd7599c9ab857b29e6"
+  integrity sha512-o96kdRKMKI3E8U0bjnfqW4QMk12MwZ4mhdBTf+B5a1q9+aq2HRnj+3ZdJu0B/ZhJeK78MgYuv6L8d/rA5AeBJA==
   dependencies:
     ansi-colors "3.2.3"
     browser-stdout "1.3.1"
+    chokidar "3.3.0"
     debug "3.2.6"
     diff "3.5.0"
     escape-string-regexp "1.0.5"
@@ -1357,18 +1424,18 @@ mocha@^6.2.2:
     growl "1.10.5"
     he "1.2.0"
     js-yaml "3.13.1"
-    log-symbols "2.2.0"
+    log-symbols "3.0.0"
     minimatch "3.0.4"
-    mkdirp "0.5.1"
+    mkdirp "0.5.5"
     ms "2.1.1"
-    node-environment-flags "1.0.5"
+    node-environment-flags "1.0.6"
     object.assign "4.1.0"
     strip-json-comments "2.0.1"
     supports-color "6.0.0"
     which "1.3.1"
     wide-align "1.1.3"
-    yargs "13.3.0"
-    yargs-parser "13.1.1"
+    yargs "13.3.2"
+    yargs-parser "13.1.2"
     yargs-unparser "1.6.0"
 
 ms@2.0.0:
@@ -1424,10 +1491,10 @@ nise@^1.5.2:
     lolex "^4.1.0"
     path-to-regexp "^1.7.0"
 
-node-environment-flags@1.0.5:
-  version "1.0.5"
-  resolved "https://registry.yarnpkg.com/node-environment-flags/-/node-environment-flags-1.0.5.tgz#fa930275f5bf5dae188d6192b24b4c8bbac3d76a"
-  integrity sha512-VNYPRfGfmZLx0Ye20jWzHUjyTW/c+6Wq+iLhDzUI4XmhrDd9l/FozXV3F2xOaXjvp0co0+v1YSR3CMP6g+VvLQ==
+node-environment-flags@1.0.6:
+  version "1.0.6"
+  resolved "https://registry.yarnpkg.com/node-environment-flags/-/node-environment-flags-1.0.6.tgz#a30ac13621f6f7d674260a54dede048c3982c088"
+  integrity sha512-5Evy2epuL+6TM0lCQGpFIj6KwiEsGh1SrHUhTbNX+sLbBtjidPZFAnVK9y5yU1+h//RitLbRHTIMyxQPtxMdHw==
   dependencies:
     object.getownpropertydescriptors "^2.0.3"
     semver "^5.7.0"
@@ -1448,6 +1515,11 @@ normalize-path@^2.0.1:
   dependencies:
     remove-trailing-separator "^1.0.1"
 
+normalize-path@^3.0.0, normalize-path@~3.0.0:
+  version "3.0.0"
+  resolved "https://registry.yarnpkg.com/normalize-path/-/normalize-path-3.0.0.tgz#0dcd69ff23a1c9b11fd0978316644a0388216a65"
+  integrity sha512-6eZs5Ls3WtCisHWp9S2GUy8dqkpGi4BVSz3GaqiE6ezub0512ESztXUwUB6C6IKbQkY2Pnb/mD4WYojCRwcwLA==
+
 object-copy@^0.1.0:
   version "0.1.0"
   resolved "https://registry.yarnpkg.com/object-copy/-/object-copy-0.1.0.tgz#7e7d858b781bd7c991a41ba975ed3812754e998c"
@@ -1613,6 +1685,11 @@ path-type@^3.0.0:
   dependencies:
     pify "^3.0.0"
 
+picomatch@^2.0.4:
+  version "2.2.2"
+  resolved "https://registry.yarnpkg.com/picomatch/-/picomatch-2.2.2.tgz#21f333e9b6b8eaff02468f5146ea406d345f4dad"
+  integrity sha512-q0M/9eZHzmr0AulXyPwNfZjtwZ/RBZlbN3K3CErVrk50T2ASYI7Bye0EvekFY3IP1Nt2DHu0re+V2ZHIpMkuWg==
+
 pify@^3.0.0:
   version "3.0.0"
   resolved "https://registry.yarnpkg.com/pify/-/pify-3.0.0.tgz#e5a4acd2c101fdf3d9a4d07f0dbc4db49dd28176"
@@ -1662,6 +1739,13 @@ read-pkg@^3.0.0:
     normalize-package-data "^2.3.2"
     path-type "^3.0.0"
 
+readdirp@~3.2.0:
+  version "3.2.0"
+  resolved "https://registry.yarnpkg.com/readdirp/-/readdirp-3.2.0.tgz#c30c33352b12c96dfb4b895421a49fd5a9593839"
+  integrity sha512-crk4Qu3pmXwgxdSgGhgA/eXiJAPQiX4GMOZZMXnqKxHX7TaoL+3gQVo/WeuAiogr07DpnfjIMpXXa+PAIvwPGQ==
+  dependencies:
+    picomatch "^2.0.4"
+
 redent@^2.0.0:
   version "2.0.0"
   resolved "https://registry.yarnpkg.com/redent/-/redent-2.0.0.tgz#c1b2007b42d57eb1389079b3c8333639d5e1ccaa"
@@ -2017,6 +2101,13 @@ to-regex-range@^2.1.0:
     is-number "^3.0.0"
     repeat-string "^1.6.1"
 
+to-regex-range@^5.0.1:
+  version "5.0.1"
+  resolved "https://registry.yarnpkg.com/to-regex-range/-/to-regex-range-5.0.1.tgz#1648c44aae7c8d988a326018ed72f5b4dd0392e4"
+  integrity sha512-65P7iz6X5yEr1cwcgvQxbbIw7Uk3gOy5dIdtZ4rDveLqhrdJP+Li/Hx6tyK0NEb+2GCyneCMJiGqrADCSNk8sQ==
+  dependencies:
+    is-number "^7.0.0"
+
 to-regex@^3.0.1, to-regex@^3.0.2:
   version "3.0.2"
   resolved "https://registry.yarnpkg.com/to-regex/-/to-regex-3.0.2.tgz#13cfdd9b336552f30b51f33a8ae1b42a7a7599ce"
@@ -2134,10 +2225,10 @@ y18n@^4.0.0:
   resolved "https://registry.yarnpkg.com/y18n/-/y18n-4.0.0.tgz#95ef94f85ecc81d007c264e190a120f0a3c8566b"
   integrity sha512-r9S/ZyXu/Xu9q1tYlpsLIsa3EeLXXk0VwlxqTcFRfg9EhMW+17kbt9G0NrgCmhGb5vT2hyhJZLfDGx+7+5Uj/w==
 
-yargs-parser@13.1.1, yargs-parser@^13.1.1:
-  version "13.1.1"
-  resolved "https://registry.yarnpkg.com/yargs-parser/-/yargs-parser-13.1.1.tgz#d26058532aa06d365fe091f6a1fc06b2f7e5eca0"
-  integrity sha512-oVAVsHz6uFrg3XQheFII8ESO2ssAf9luWuAd6Wexsu4F3OtIW0o8IribPXYrD4WC24LWtPrJlGy87y5udK+dxQ==
+yargs-parser@13.1.2, yargs-parser@^13.1.2:
+  version "13.1.2"
+  resolved "https://registry.yarnpkg.com/yargs-parser/-/yargs-parser-13.1.2.tgz#130f09702ebaeef2650d54ce6e3e5706f7a4fb38"
+  integrity sha512-3lbsNRf/j+A4QuSZfDRA7HRSfWrzO0YjqTJd5kjAq37Zep1CEgaYmrH9Q3GwPiB9cHyd1Y1UwggGhJGoxipbzg==
   dependencies:
     camelcase "^5.0.0"
     decamelize "^1.2.0"
@@ -2158,10 +2249,10 @@ yargs-unparser@1.6.0:
     lodash "^4.17.15"
     yargs "^13.3.0"
 
-yargs@13.3.0, yargs@^13.3.0:
-  version "13.3.0"
-  resolved "https://registry.yarnpkg.com/yargs/-/yargs-13.3.0.tgz#4c657a55e07e5f2cf947f8a366567c04a0dedc83"
-  integrity sha512-2eehun/8ALW8TLoIl7MVaRUrg+yCnenu8B4kBlRxj3GJGDKU1Og7sMXPNm1BYyM1DOJmTZ4YeN/Nwxv+8XJsUA==
+yargs@13.3.2, yargs@^13.3.0:
+  version "13.3.2"
+  resolved "https://registry.yarnpkg.com/yargs/-/yargs-13.3.2.tgz#ad7ffefec1aa59565ac915f82dccb38a9c31a2dd"
+  integrity sha512-AX3Zw5iPruN5ie6xGRIDgqkT+ZhnRlZMLMHAs8tg7nRruy2Nb+i5o9bwghAogtM08q1dpr2LVoS8KSTMYpWXUw==
   dependencies:
     cliui "^5.0.0"
     find-up "^3.0.0"
@@ -2172,7 +2263,7 @@ yargs@13.3.0, yargs@^13.3.0:
     string-width "^3.0.0"
     which-module "^2.0.0"
     y18n "^4.0.0"
-    yargs-parser "^13.1.1"
+    yargs-parser "^13.1.2"
 
 yn@3.1.1:
   version "3.1.1"