Normalize native error properties

Map native error properties to the same property names we use for errors from the JS driver.

Fixes #972
Fixes #938

Author: brianc

lib/native/query.js

@@ -51,13 +51,29 @@ NativeQuery.prototype.promise = function() {
   return this._promise;
 };
 
+var errorFieldMap = {
+  'sqlState': 'code',
+  'statementPosition': 'position',
+  'messagePrimary': 'message',
+  'context': 'where',
+  'schemaName': 'schema',
+  'tableName': 'table',
+  'columnName': 'column',
+  'dataTypeName': 'dataType',
+  'constraintName': 'constraint',
+  'sourceFile': 'file',
+  'sourceLine': 'line',
+  'sourceFunction': 'routine',
+};
+
 NativeQuery.prototype.handleError = function(err) {
   var self = this;
   //copy pq error fields into the error object
   var fields = self.native.pq.resultErrorFields();
   if(fields) {
     for(var key in fields) {
-      err[key] = fields[key];
+      var normalizedFieldName = errorFieldMap[key] || key;
+      err[normalizedFieldName] = fields[key];
     }
   }
   if(self.callback) {

test/native/native-vs-js-error-tests.js

@@ -0,0 +1,20 @@
+var assert = require('assert')
+var Client = require('../../lib/client');
+var NativeClient = require('../../lib/native');
+
+var client = new Client();
+var nativeClient = new NativeClient();
+
+client.connect();
+nativeClient.connect((err) => {
+  client.query('SELECT alsdkfj', (err) => {
+    client.end();
+
+    nativeClient.query('SELECT lkdasjfasd', (nativeErr) => {
+      for(var key in nativeErr) {
+        assert.equal(err[key], nativeErr[key], `Expected err.${key} to equal nativeErr.${key}`)
+      }
+      nativeClient.end();
+    });
+  });
+});