Add testem as a main test runner

.testem.json

@@ -0,0 +1,14 @@
+{
+  "framework": "custom",
+  "src_files": [
+    "src/**/*.js",
+    "test/**/*.js"
+  ],
+  "launchers": {
+    "tap": {
+      "command": "ava test/**/*.js --tap",
+      "protocol": "tap"
+    }
+  },
+  "launch_in_dev": [ "tap" ]
+}

package.json

@@ -25,7 +25,8 @@
     "babel-cli": "^6.24.1",
     "babel-preset-env": "^1.3.3",
     "babel-register": "^6.24.1",
-    "sinon": "^2.1.0"
+    "sinon": "^2.1.0",
+    "testem": "^1.16.2"
   },
   "ava": {
     "require": [
@@ -40,7 +41,7 @@
     "test": "test"
   },
   "scripts": {
-    "test": "ava",
+    "test": "testem",
     "prepublish": "make boosh"
   },
   "license": "MIT"