Fix transaction post_date being set to midnight local.

Reported for Invoices on gnucash-user. Checked all other uses of
xaccTransSetPostDateSecs(), fixed the ones that weren't passing an
already normalized time64. For Invoices change the post_date to also be
normalized so that it stays the same as the transaction post_date. That
also protects it from the displayed date changing depending on timezone.

The python binding invoice post_time test had to be changed to match.

bindings/python/tests/test_business.py

@@ -1,6 +1,6 @@
 from unittest import main
 
-from datetime import datetime, timedelta
+from datetime import datetime, timezone
 
 from gnucash import Account, \
     ACCT_TYPE_RECEIVABLE, ACCT_TYPE_INCOME, ACCT_TYPE_BANK, \
@@ -56,8 +56,8 @@ def test_employee_name(self):
         self.assertEqual( NAME, self.employee.GetUsername() )
 
     def test_post(self):
-        self.assertEqual(self.today - timedelta(0, 0, self.today.microsecond),
-                         self.invoice.GetDatePosted())
+        self.assertEqual(datetime.now(timezone.utc).replace(hour=10, minute=59, second=0, microsecond=0).astimezone(),
+                         self.invoice.GetDatePosted().astimezone())
         self.assertTrue( self.invoice.IsPosted() )
 
     def test_owner(self):

gnucash/gnome-utils/dialog-transfer.c

@@ -1514,7 +1514,7 @@ create_transaction(XferDialog *xferData, time64 time,
     xaccTransBeginEdit(trans);
 
     xaccTransSetCurrency(trans, xferData->from_commodity);
-    xaccTransSetDatePostedSecs(trans, time);
+    xaccTransSetDatePostedSecsNormalized(trans, time);
 
     /* Trans-Num or Split-Action set with gnc_set_num_action below per book
      * option */

gnucash/gnome-utils/gnc-tree-view-split-reg.c

@@ -2450,7 +2450,7 @@ gtv_sr_begin_edit (GncTreeViewSplitReg *view, Transaction *trans)
             //is a new transaction and set the time to current time to show current
             //date on new transactions
             time = gnc_time (NULL);
-            xaccTransSetDatePostedSecs (trans, time);
+            xaccTransSetDatePostedSecsNormalized (trans, time);
         }
     }
     LEAVE(" ");

libgnucash/engine/gncInvoice.c

@@ -1506,8 +1506,8 @@ Transaction * gncInvoicePostToAccount (GncInvoice *invoice, Account *acc,
 
     /* Entered and Posted at date */
     xaccTransSetDateEnteredSecs (txn, gnc_time (NULL));
-    xaccTransSetDatePostedSecs (txn, post_date);
-    gncInvoiceSetDatePosted (invoice, post_date);
+    xaccTransSetDatePostedSecsNormalized (txn, post_date);
+    gncInvoiceSetDatePosted (invoice, xaccTransRetDatePosted(txn));
 
     xaccTransSetDateDue (txn, due_date);