From 5326608d5131be2ab069af8d935e3bb65f9b3edc Mon Sep 17 00:00:00 2001
From: James Saryerwinnie <js@jamesls.com>
Date: Sat, 19 Dec 2015 10:25:49 -0800
Subject: [PATCH 1/3] Proof of concept for .cd command

Proposed in #76.

Still needs discussion for whether or not this
should be a dot command.  If we go with this
approach the only thing left is tests.
---
 awsshell/app.py | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/awsshell/app.py b/awsshell/app.py
index 218e2b0..220e2cb 100644
--- a/awsshell/app.py
+++ b/awsshell/app.py
@@ -45,6 +45,19 @@ class InputInterrupt(Exception):
     pass
 
 
+class ChangeDirHandler(object):
+    def run(self, command, application):
+        # command is a list of parsed commands
+        if len(command) != 2:
+            sys.stderr.write("invalid syntax, must be: .cd dirname\n")
+            return
+        dirname = os.path.expandvars(os.path.expanduser(command[1]))
+        try:
+            os.chdir(dirname)
+        except OSError as e:
+            sys.stderr.write("cd: %s\n" % e)
+
+
 class EditHandler(object):
     def __init__(self, popen_cls=None, env=None):
         if popen_cls is None:
@@ -85,6 +98,7 @@ def run(self, command, application):
 class DotCommandHandler(object):
     HANDLER_CLASSES = {
         'edit': EditHandler,
+        'cd': ChangeDirHandler,
     }
 
     def __init__(self, output=sys.stdout, err=sys.stderr):

From b06e27ad95ebd2059bdc05b44ec8d2edbcf175b4 Mon Sep 17 00:00:00 2001
From: James Saryerwinnie <js@jamesls.com>
Date: Tue, 29 Dec 2015 17:20:49 -0800
Subject: [PATCH 2/3] Add tests for .cd dot command

---
 awsshell/app.py        | 11 ++++++++---
 tests/unit/test_app.py | 23 +++++++++++++++++++++++
 2 files changed, 31 insertions(+), 3 deletions(-)

diff --git a/awsshell/app.py b/awsshell/app.py
index 220e2cb..b8c29a7 100644
--- a/awsshell/app.py
+++ b/awsshell/app.py
@@ -46,16 +46,21 @@ class InputInterrupt(Exception):
 
 
 class ChangeDirHandler(object):
+    def __init__(self, output=sys.stdout, err=sys.stderr, chdir=os.chdir):
+        self._output = output
+        self._err = err
+        self._chdir = chdir
+
     def run(self, command, application):
         # command is a list of parsed commands
         if len(command) != 2:
-            sys.stderr.write("invalid syntax, must be: .cd dirname\n")
+            self._err.write("invalid syntax, must be: .cd dirname\n")
             return
         dirname = os.path.expandvars(os.path.expanduser(command[1]))
         try:
-            os.chdir(dirname)
+            self._chdir(dirname)
         except OSError as e:
-            sys.stderr.write("cd: %s\n" % e)
+            self._err.write("cd: %s\n" % e)
 
 
 class EditHandler(object):
diff --git a/tests/unit/test_app.py b/tests/unit/test_app.py
index 9702545..f8397a8 100644
--- a/tests/unit/test_app.py
+++ b/tests/unit/test_app.py
@@ -42,3 +42,26 @@ def test_prints_error_message_on_unknown_dot_command(errstream):
     handler = app.DotCommandHandler(err=errstream)
     handler.handle_cmd(".unknown foo bar", None)
     assert errstream.getvalue() == "Unknown dot command: .unknown\n"
+
+
+def test_cd_handler_can_chdir():
+    chdir = mock.Mock()
+    handler = app.ChangeDirHandler(chdir=chdir)
+    handler.run(['.cd', 'foo/bar'], None)
+    assert chdir.call_args == mock.call('foo/bar')
+
+
+def test_chdir_syntax_error_prints_err_msg(errstream):
+    chdir = mock.Mock()
+    handler = app.ChangeDirHandler(err=errstream, chdir=chdir)
+    handler.run(['.cd'], None)
+    assert 'invalid syntax' in errstream.getvalue()
+    assert not chdir.called
+
+
+def test_error_displayed_when_chdir_fails(errstream):
+    chdir = mock.Mock()
+    chdir.side_effect = OSError("FAILED")
+    handler = app.ChangeDirHandler(err=errstream, chdir=chdir)
+    handler.run(['.cd', 'foo'], None)
+    assert 'FAILED' in errstream.getvalue()

From 4e84552f367f4da647e10be05795b870c112e3bb Mon Sep 17 00:00:00 2001
From: James Saryerwinnie <js@jamesls.com>
Date: Tue, 29 Dec 2015 17:44:02 -0800
Subject: [PATCH 3/3] Update README with docs for .cd command

---
 README.rst | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/README.rst b/README.rst
index 223e1f1..bfbecb0 100644
--- a/README.rst
+++ b/README.rst
@@ -219,6 +219,19 @@ variable before defaulting to ``notepad`` on Windows and
     aws> .edit
 
 
+.cd
+~~~
+
+You can change the current working directory of the aws-shell by using
+the ``.cd`` command::
+
+    aws> !pwd
+    /usr
+    aws> .cd /tmp
+    aws> !pwd
+    /tmp
+
+
 Executing Shell Commands
 ------------------------