Prompt and line now properly echoed on tty and pipe

if we are on a pipe, we have to echo the prompt only after we read and are not at EOF.

Author: kotfu

cmd2.py

@@ -970,25 +970,45 @@ def _surround_ansi_escapes(prompt, start="\x01", end="\x02"):
         return result
 
     def pseudo_raw_input(self, prompt):
-        """copied from cmd's cmdloop; like raw_input, but accounts for changed stdin, stdout"""
+        """
+        began life as a copy of cmd's cmdloop; like raw_input but
+        
+        - accounts for changed stdin, stdout
+        - if input is a pipe (instead of a tty), look at self.echo
+          to decide whether to print the prompt and the input
+        """
 
         # Deal with the vagaries of readline and ANSI escape codes
         safe_prompt = self._surround_ansi_escapes(prompt)
 
         if self.use_rawinput:
             try:
-                line = sm.input(safe_prompt)
+                if sys.stdin.isatty():
+                    sys.stdout.write(safe_prompt)
+                    line = sm.input()
+                else:
+                    line = sm.input()
+                    if self.echo:
+                        sys.stdout.write('{}{}\n'.format(safe_prompt,line))
             except EOFError:
                 line = 'eof'
         else:
-            self.poutput(safe_prompt, end='')
-            self.stdout.flush()
-            line = self.stdin.readline()
-            if not len(line):
-                line = 'eof'
+            if self.stdin.isatty():
+                # on a tty, print the prompt first, then read the line
+                self.poutput(safe_prompt, end='')
+                self.stdout.flush()
+                line = self.stdin.readline()
             else:
-                line = line.rstrip('\r\n')
-
+                # we are reading from a pipe, read the line to see if there is
+                # anything there, if so, then decide whether to print the
+                # prompt or not
+                line = self.stdin.readline()
+                if len(line):
+                    # we read something, output the prompt and the something
+                    if self.echo:
+                        self.poutput('{}{}'.format(safe_prompt, line))
+                else:
+                    line = 'eof'
         return line.strip()
 
     def _cmdloop(self):

tests/test_cmd2.py

@@ -7,6 +7,7 @@
 """
 import os
 import sys
+import io
 import tempfile
 
 import mock
@@ -849,6 +850,7 @@ def test_cmdloop_without_rawinput():
     # Create a cmd2.Cmd() instance and make sure basic settings are like we want for test
     app = cmd2.Cmd()
     app.use_rawinput = False
+    app.echo = False
     app.intro = 'Hello World, this is an intro ...'
     app.stdout = StdOut()
 
@@ -858,7 +860,7 @@ def test_cmdloop_without_rawinput():
 
     # Need to patch sys.argv so cmd2 doesn't think it was called with arguments equal to the py.test args
     testargs = ["prog"]
-    expected = app.intro + '\n{}'.format(app.prompt)
+    expected = app.intro + '\n'
     with mock.patch.object(sys, 'argv', testargs):
         # Run the command loop
         app.cmdloop()
@@ -1388,7 +1390,54 @@ def test_echo(capsys):
     assert app._current_script_dir is None
     assert out.startswith('{}{}\n'.format(app.prompt, command) + 'history [arg]: lists past commands issued')
 
+#@pytest.mark.parametrize('rawinput', [True, False])
+def test_piped_input_echo_false(capsys):
+    command = 'set'
+
+    # hack up stdin
+    fakein = io.StringIO(command)
+    #realin = sys.stdin
+    #sys.stdin = fakein
+
+    # run the cmdloop, which should pull input from stdin
+    app = cmd2.Cmd(stdin=fakein)
+    app.use_rawinput = False
+    app.echo = False
+    app.abbrev = False
+    app._cmdloop()
+    out, err = capsys.readouterr()
+
+    # put stdin back
+    #sys.stdin = realin
+
+    firstline = out.splitlines()[0]
+    assert firstline == 'abbrev: False'
+    assert not '{}{}'.format(app.prompt, command) in out
+
+#@pytest.mark.parametrize('rawinput', [True, False])
+def test_piped_input_echo_true(capsys):
+    command = 'set'
+
+    # hack up stdin
+    fakein = io.StringIO(command)
+    # realin = sys.stdin
+    # sys.stdin = fakein
+
+    # run the cmdloop, which should pull input from stdin
+    app = cmd2.Cmd(stdin=fakein)
+    app.use_rawinput = False
+    app.echo = True
+    app.abbrev = False
+    app._cmdloop()
+    out, err = capsys.readouterr()
+
+    # put stdin back
+    # sys.stdin = realin
 
+    out = out.splitlines()
+    assert out[0] == '{}{}'.format(app.prompt, command)
+    assert out[1] == 'abbrev: False'
+        
 def test_raw_input(base_app):
     base_app.use_raw_input = True
     fake_input = 'quit'