safe_psql() should always raise error on wrong input (issue #52)

Author: funbringer

Diff for: testgres/node.py

@@ -812,7 +812,8 @@ def psql(self,
              filename=None,
              dbname=None,
              username=None,
-             input=None):
+             input=None,
+             **kwargs):
         """
         Execute a query using psql.
 
@@ -822,9 +823,18 @@ def psql(self,
             dbname: database name to connect to.
             username: database user name.
             input: raw input to be passed.
+            **kwargs: variables to be set before execution.
 
         Returns:
             A tuple of (code, stdout, stderr).
+
+        Examples:
+            >>> psql('select 1')
+            (0, b'1\n', b'')
+            >>> psql('postgres', 'select 2')
+            (0, b'2\n', b'')
+            >>> psql(query='select 3', ON_ERROR_STOP=1)
+            (0, b'3\n', b'')
         """
 
         # Set default arguments
@@ -843,6 +853,10 @@ def psql(self,
             dbname
         ]  # yapf: disable
 
+        # set variables before execution
+        for key, value in iteritems(kwargs):
+            psql_params.extend(["--set", '{}={}'.format(key, value)])
+
         # select query source
         if query:
             psql_params.extend(("-c", query))
@@ -874,10 +888,15 @@ def safe_psql(self, query=None, **kwargs):
             username: database user name.
             input: raw input to be passed.
 
+            **kwargs are passed to psql().
+
         Returns:
             psql's output as str.
         """
 
+        # force this setting
+        kwargs['ON_ERROR_STOP'] = 1
+
         ret, out, err = self.psql(query=query, **kwargs)
         if ret:
             raise QueryException((err or b'').decode('utf-8'), query)