Added PostgresNode.__repr__() method and fix doctests

Author: zilder

testgres/api.py

@@ -7,27 +7,27 @@
 edit configuration files, start/stop cluster, execute queries. The
 typical flow may look like:
 
->>> with get_new_node() as node:
+>>> with get_new_node('test') as node:
 ...     node.init().start()
 ...     result = node.safe_psql('postgres', 'select 1')
 ...     print(result.decode('utf-8').strip())
 ...     node.stop()
-<testgres.node.PostgresNode object at 0x...>
+PostgresNode('test', port=..., base_dir=...)
 1
-<testgres.node.PostgresNode object at 0x...>
+PostgresNode('test', port=..., base_dir=...)
 
     Or:
 
->>> with get_new_node() as master:
+>>> with get_new_node('master') as master:
 ...     master.init().start()
 ...     with master.backup() as backup:
-...         with backup.spawn_replica() as replica:
+...         with backup.spawn_replica('replica') as replica:
 ...             replica = replica.start()
 ...             master.execute('postgres', 'create table test (val int4)')
 ...             master.execute('postgres', 'insert into test values (0), (1), (2)')
 ...             replica.catchup()  # wait until changes are visible
 ...             print(replica.execute('postgres', 'select count(*) from test'))
-<testgres.node.PostgresNode object at 0x...>
+PostgresNode('master', port=..., base_dir=...)
 [(3,)]
 
 Copyright (c) 2016, Postgres Professional

testgres/config.py

@@ -152,9 +152,11 @@ def scoped_config(**options):
     Temporarily set custom GlobalConfig options for this context.
 
     Example:
+        >>> from .api import get_new_node
         >>> with scoped_config(cache_initdb=False):
         ...     with get_new_node().init().start() as node:
         ...         print(node.execute('select 1'))
+        [(1,)]
     """
 
     try:

testgres/node.py

@@ -135,6 +135,10 @@ def __exit__(self, type, value, traceback):
         else:
             self._try_shutdown(attempts)
 
+    def __repr__(self):
+        return "PostgresNode('{}', port={}, base_dir={})".format(
+            self.name, self.port, self.base_dir)
+
     @property
     def pid(self):
         """