diff --git a/src/shell.js b/src/shell.js
index c53699a..4b31b81 100644
--- a/src/shell.js
+++ b/src/shell.js
@@ -2,11 +2,12 @@
 define(function(require) {
 
   var Path = require('src/path');
+  var Error = require('src/error');
 
   function Shell(fs, options) {
     options = options || {};
 
-    var cwd = options.cwd || '/';
+    var cwd = '/';
 
     Object.defineProperty(this, 'fs', {
       get: function() { return fs; },
@@ -20,10 +21,22 @@ define(function(require) {
 
     // We include `cd` on the this vs. proto so that
     // we can access cwd without exposing it externally.
-    this.cd = function(path) {
-      this.cwd = Path.resolve(this.cwd, path);
+    this.cd = function(path, callback) {
+      path = Path.resolve(this.cwd, path);
+      // Make sure the path actually exists, and is a dir
+      fs.stat(path, function(err, stats) {
+        if(err) {
+          callback(new Error.ENotDirectory());
+          return;
+        }
+        if(stats.type === 'DIRECTORY') {
+          cwd = path;
+          callback();
+        } else {
+          callback(new Error.ENotDirectory());
+        }
+      });
     };
-
   }
 
   /**
@@ -83,9 +96,7 @@ define(function(require) {
     path = Path.resolve(this.cwd, path);
 
     function createFile(path) {
-      fs.writeFile(path, '', function(error) {
-        callback(error);
-      });
+      fs.writeFile(path, '', callback);
     }
 
     function updateTimes(path) {
@@ -93,9 +104,7 @@ define(function(require) {
       var atime = options.date || now;
       var mtime = options.date || now;
 
-      fs.utimes(path, atime, mtime, function(error) {
-        callback(error);
-      });
+      fs.utimes(path, atime, mtime, callback);
     }
 
     fs.stat(path, function(error, stats) {
diff --git a/tests/spec/shell/cd.spec.js b/tests/spec/shell/cd.spec.js
new file mode 100644
index 0000000..8f01264
--- /dev/null
+++ b/tests/spec/shell/cd.spec.js
@@ -0,0 +1,104 @@
+define(["Filer", "util"], function(Filer, util) {
+
+  describe('FileSystemShell.cd', function() {
+    beforeEach(util.setup);
+    afterEach(util.cleanup);
+
+    it('should be a function', function() {
+      var shell = util.shell();
+      expect(shell.cd).to.be.a('function');
+    });
+
+    it('should default to a cwd of /', function() {
+      var shell = util.shell();
+      expect(shell.cwd).to.equal('/');
+    });
+
+    it('should allow changing the path to a valid dir', function(done) {
+      var fs = util.fs();
+      var shell = fs.Shell();
+
+      fs.mkdir('/dir', function(err) {
+        if(err) throw err;
+
+        expect(shell.cwd).to.equal('/');
+        shell.cd('/dir', function(err) {
+          expect(err).not.to.exist;
+          expect(shell.cwd).to.equal('/dir');
+          done();
+        });
+      });
+    });
+
+    it('should fail when changing the path to an invalid dir', function(done) {
+      var fs = util.fs();
+      var shell = fs.Shell();
+
+      fs.mkdir('/dir', function(err) {
+        if(err) throw err;
+
+        expect(shell.cwd).to.equal('/');
+        shell.cd('/nodir', function(err) {
+          expect(err).to.exist;
+          expect(err.name).to.equal('ENotDirectory');
+          expect(shell.cwd).to.equal('/');
+          done();
+        });
+      });
+    });
+
+    it('should fail when changing the path to a file', function(done) {
+      var fs = util.fs();
+      var shell = fs.Shell();
+
+      fs.writeFile('/file', 'file', function(err) {
+        if(err) throw err;
+
+        expect(shell.cwd).to.equal('/');
+        shell.cd('/file', function(err) {
+          expect(err).to.exist;
+          expect(err.name).to.equal('ENotDirectory');
+          expect(shell.cwd).to.equal('/');
+          done();
+        });
+      });
+    });
+
+    it('should allow relative paths for a valid dir', function(done) {
+      var fs = util.fs();
+      var shell = fs.Shell();
+
+      fs.mkdir('/dir', function(err) {
+        if(err) throw err;
+
+        expect(shell.cwd).to.equal('/');
+        shell.cd('./dir', function(err) {
+          expect(err).not.to.exist;
+          expect(shell.cwd).to.equal('/dir');
+          done();
+        });
+      });
+    });
+
+    it('should allow .. in paths for a valid dir', function(done) {
+      var fs = util.fs();
+      var shell = fs.Shell();
+
+      fs.mkdir('/dir', function(err) {
+        if(err) throw err;
+
+        expect(shell.cwd).to.equal('/');
+        shell.cd('./dir', function(err) {
+          expect(err).not.to.exist;
+          expect(shell.cwd).to.equal('/dir');
+          shell.cd('..', function(err) {
+            expect(err).not.to.exist;
+            expect(shell.cwd).to.equal('/');
+            done();
+          });
+        });
+      });
+    });
+
+  });
+});
diff --git a/tests/test-manifest.js b/tests/test-manifest.js
index 3faf91d..2fa4f63 100644
--- a/tests/test-manifest.js
+++ b/tests/test-manifest.js
@@ -43,6 +43,7 @@ define([
   "spec/adapters/adapters.general.spec",
 
   // Filer.FileSystemShell.*
+  "spec/shell/cd.spec",
   "spec/shell/touch.spec",
   "spec/shell/exec.spec",