date type coercion works in both directions

lib/client.js

@@ -144,8 +144,12 @@ p.hasBeenParsed = function(connection) {
 
 p.prepare = function(connection) {
   var self = this;
-
   var onParseComplete = function() {
+    if(self.values) {
+      self.values = self.values.map(function(val) {
+        return (val instanceof Date) ? JSON.stringify(val) : val;
+      });
+    }
     connection.bind({
       portal: self.name,
       statement: self.name,
@@ -260,9 +264,9 @@ var dateParser = function(isoDate) {
       throw new Error("Unidentifed tZone part " + type);
     }
   }
-  
+
   var utcOffset = Date.UTC(year, month, day, hour, min, seconds, mili);
-  
+
   var date = new Date(utcOffset - (tzAdjust * 60* 1000));
   return date;
 };

test/integration/client/type-coercion-tests.js

@@ -77,4 +77,34 @@ var types = [{
 
 types.forEach(testForTypeCoercion);
 
+test("timestampz round trip", function() {
+  var now = new Date();
+  var client = helper.client();
+  client.on('error', function(err) {
+    console.log(err);
+    client.end();
+  });
+  client.query("create temp table date_tests(name varchar(10), tstz timestamptz(3))");
+  client.query({
+    text: "insert into date_tests(name, tstz)VALUES($1, $2)",
+    name: 'add date',
+    values: ['now', now]
+  });
+  var result = client.query({
+    name: 'get date',
+    text: 'select * from date_tests where name = $1',
+    values: ['now']
+  });
+  assert.emits(result, 'row', function(row) {
+    var date = row.fields[1];
+    assert.equal(date.getYear(),now.getYear());
+    assert.equal(date.getMonth(), now.getMonth());
+    assert.equal(date.getDate(), now.getDate());
+    assert.equal(date.getHours(), now.getHours());
+    assert.equal(date.getMinutes(), now.getMinutes());
+    assert.equal(date.getSeconds(), now.getSeconds());
+    assert.equal(date.getMilliseconds(), now.getMilliseconds());
+  });
+  client.on('drain', client.end.bind(client));
+});