Fire close callback when ready for next query

Working on fixing some timing issues in pg-query-stream it uncovered an issue where the cursor is firing its 'close' callback before it's actually entirely ready to dispatch another query.  This change makes the close callback trigger when the connection re-enters `readyForQuery` state.

packages/pg-cursor/index.js

@@ -6,7 +6,7 @@ const util = require('util')
 
 let nextUniqueID = 1 // concept borrowed from org.postgresql.core.v3.QueryExecutorImpl
 
-function Cursor (text, values, config) {
+function Cursor(text, values, config) {
   EventEmitter.call(this)
 
   this._conf = config || {}
@@ -192,7 +192,7 @@ Cursor.prototype.close = function (cb) {
   this._closePortal()
   this.state = 'done'
   if (cb) {
-    this.connection.once('closeComplete', function () {
+    this.connection.once('readyForQuery', function () {
       cb()
     })
   }

packages/pg-cursor/test/close.js

@@ -7,7 +7,10 @@ describe('close', function () {
   beforeEach(function (done) {
     const client = (this.client = new pg.Client())
     client.connect(done)
-    client.on('drain', client.end.bind(client))
+  })
+
+  this.afterEach(function (done) {
+    this.client.end(done)
   })
 
   it('can close a finished cursor without a callback', function (done) {
@@ -34,8 +37,9 @@ describe('close', function () {
     const cursor = new Cursor(text)
     const client = this.client
     client.query(cursor)
-    cursor.read(25, function (err) {
+    cursor.read(25, function (err, rows) {
       assert.ifError(err)
+      assert.strictEqual(rows.length, 25)
       cursor.close(function (err) {
         assert.ifError(err)
         client.query('SELECT NOW()', done)