Merge pull request #619 from python-cmd2/string_stream

Fixed buffering issue when echoing StdSim data

Author: kmvanbrunt

CHANGELOG.md

@@ -1,3 +1,8 @@
+## 0.9.8 (TBD, 2019)
+* Bug Fixes
+    * Fixed issue with echoing strings in StdSim. Because they were being sent to a binary buffer, line buffering
+    was being ignored.
+
 ## 0.9.7 (January 08, 2019)
 * Bug Fixes
     * Fixed bug when user chooses a zero or negative index when calling ``Cmd.select()``

cmd2/utils.py

@@ -281,10 +281,7 @@ def write(self, b: bytes) -> None:
                 raise TypeError('a bytes-like object is required, not {}'.format(type(b)))
             self.byte_buf += b
             if self.echo:
-                if hasattr(self.inner_stream, 'buffer'):
-                    self.inner_stream.buffer.write(b)
-                else:
-                    self.inner_stream.write(b.decode(encoding=self.encoding, errors=self.errors))
+                self.inner_stream.buffer.write(b)
 
     def __init__(self, inner_stream, echo: bool = False,
                  encoding: str='utf-8', errors: str='replace') -> None:
@@ -297,15 +294,17 @@ def __init__(self, inner_stream, echo: bool = False,
         """
         self.buffer = self.ByteBuf(inner_stream, echo)
         self.inner_stream = inner_stream
+        self.echo = echo
         self.encoding = encoding
         self.errors = errors
 
     def write(self, s: str) -> None:
         """Add str to internal bytes buffer and if echo is True, echo contents to inner stream"""
         if not isinstance(s, str):
             raise TypeError('write() argument must be str, not {}'.format(type(s)))
-        b = s.encode(encoding=self.encoding, errors=self.errors)
-        self.buffer.write(b)
+        self.buffer.byte_buf += s.encode(encoding=self.encoding, errors=self.errors)
+        if self.echo:
+            self.inner_stream.write(s)
 
     def getvalue(self) -> str:
         """Get the internal contents as a str"""

tests/test_utils.py

@@ -122,7 +122,7 @@ def test_quot_string_if_needed_no():
 
 @pytest.fixture
 def stdout_sim():
-    stdsim = cu.StdSim(sys.stdout)
+    stdsim = cu.StdSim(sys.stdout, echo=True)
     return stdsim
 
 @pytest.fixture