Add txn 1st seen height to bid.

Format balance amount.
Start prepare script.

tests/__init__.py

@@ -1,11 +1,14 @@
 import unittest
 
-import tests.test_run
 import tests.test_other
+import tests.test_prepare
+import tests.test_run
 
 
 def test_suite():
     loader = unittest.TestLoader()
-    suite = loader.loadTestsFromModule(tests.test_run)
     suite.addTests(loader.loadTestsFromModule(tests.test_other))
+    suite.addTests(loader.loadTestsFromModule(tests.test_prepare))
+    suite = loader.loadTestsFromModule(tests.test_run)
+
     return suite

tests/test_prepare.py

@@ -0,0 +1,51 @@
+#!/usr/bin/env python3
+# -*- coding: utf-8 -*-
+
+# Copyright (c) 2019 tecnovert
+# Distributed under the MIT software license, see the accompanying
+# file LICENSE.txt or http://www.opensource.org/licenses/mit-license.php.
+
+import os
+import sys
+import unittest
+from unittest.mock import patch
+from io import StringIO
+import logging
+import shutil
+import importlib
+
+prepareSystem = importlib.import_module('bin.basicswap-prepare')
+test_path = os.path.expanduser('~/test_basicswap')
+
+logger = logging.getLogger()
+logger.level = logging.DEBUG
+
+
+class Test(unittest.TestCase):
+    @classmethod
+    def tearDownClass(self):
+        try:
+            shutil.rmtree(test_path)
+        except Exception as e:
+            logger.warning('tearDownClass %s', str(e))
+
+    def test_no_overwrite(self):
+        testargs = ['basicswap-prepare', '-datadir=' + test_path]
+        with patch.object(sys, 'argv', testargs):
+            prepareSystem.main()
+
+        self.assertTrue(os.path.exists(os.path.join(test_path, 'basicswap.json')))
+
+        testargs = ['basicswap-prepare', '-datadir=' + test_path]
+        with patch('sys.stderr', new=StringIO()) as fake_stderr:
+            with patch.object(sys, 'argv', testargs):
+                with self.assertRaises(SystemExit) as cm:
+                    prepareSystem.main()
+
+        self.assertEqual(cm.exception.code, 1)
+        logger.info('fake_stderr.getvalue() %s', fake_stderr.getvalue())
+        self.assertTrue('exists, exiting' in fake_stderr.getvalue())
+
+
+if __name__ == '__main__':
+    unittest.main()