replace jest with ava

node_modules/concordance/lib/Registry.js

@@ -0,0 +1,24 @@
+'use strict'
+
+class Registry {
+  constructor () {
+    this.counter = 0
+    this.map = new WeakMap()
+  }
+
+  has (value) {
+    return this.map.has(value)
+  }
+
+  get (value) {
+    return this.map.get(value).descriptor
+  }
+
+  alloc (value) {
+    const index = ++this.counter
+    const pointer = {descriptor: null, index}
+    this.map.set(value, pointer)
+    return pointer
+  }
+}
+module.exports = Registry