diff --git a/spec/atom/editor-spec.coffee b/spec/atom/editor-spec.coffee
index 5e03e9f72..094077dea 100644
--- a/spec/atom/editor-spec.coffee
+++ b/spec/atom/editor-spec.coffee
@@ -1,3 +1,4 @@
+Buffer = require 'buffer'
 Editor = require 'editor'
 $ = require 'jquery'
 ck = require 'coffeekup'
@@ -29,6 +30,20 @@ describe "Editor", ->
       editor.destroy()
       expect(editor.aceEditor.destroy).toHaveBeenCalled()
 
+  describe "setBuffer(buffer)", ->
+    it "sets the document on the aceSession", ->
+      buffer = new Buffer filePath
+      editor.setBuffer buffer
+
+      fileContents = fs.read(filePath)
+      expect(editor.getAceSession().getValue()).toBe fileContents
+
+    it "sets the language mode based on the file extension", ->
+      buffer = new Buffer "something.js"
+      editor.setBuffer buffer
+
+      expect(editor.getAceSession().getMode().name).toBe 'javascript'
+
   describe "open(url)", ->
     describe "when called with a url", ->
       it "loads a buffer for the given url into the editor", ->
diff --git a/spec/atom/root-view-spec.coffee b/spec/atom/root-view-spec.coffee
index 5cd656b69..a2d3ee5a8 100644
--- a/spec/atom/root-view-spec.coffee
+++ b/spec/atom/root-view-spec.coffee
@@ -51,7 +51,7 @@ describe "RootView", ->
           rootView.toggleFileFinder()
           expect(rootView.find('.file-finder')).not.toExist()
 
-      fit "shows all relative file paths for the current project", ->
+      it "shows all relative file paths for the current project", ->
         waitsForPromise ->
           rootView.toggleFileFinder()
 
@@ -73,7 +73,7 @@ describe "RootView", ->
         rootView.toggleFileFinder()
         expect(rootView.find('.file-finder')).not.toExist()
 
-  fdescribe "when a path is selected in the file finder", ->
+  describe "when a path is selected in the file finder", ->
     it "opens the file associated with that path in the editor", ->
       waitsForPromise -> rootView.toggleFileFinder()
       runs ->
diff --git a/src/atom/editor.coffee b/src/atom/editor.coffee
index 7d9a7a7dd..9cf6f3fe7 100644
--- a/src/atom/editor.coffee
+++ b/src/atom/editor.coffee
@@ -12,7 +12,6 @@ class Editor extends Template
   viewProperties:
     aceEditor: null
     buffer: null
-    editorElement: null
 
     initialize: () ->
       @buildAceEditor()
@@ -24,11 +23,13 @@ class Editor extends Template
     destroy: ->
       @aceEditor.destroy()
 
-    open: (url) ->
-      @buffer = new Buffer(url)
+    setBuffer: (@buffer) ->
       session = new EditSession(@buffer.aceDocument, @buffer.getMode())
       @aceEditor.setSession(session)
 
+    open: (url) ->
+      @setBuffer(new Buffer(url))
+
     buildAceEditor: ->
       @aceEditor = ace.edit this[0]
       @aceEditor.setTheme(require "ace/theme/twilight")
diff --git a/src/atom/root-view.coffee b/src/atom/root-view.coffee
index 15d088aee..6e51e798f 100644
--- a/src/atom/root-view.coffee
+++ b/src/atom/root-view.coffee
@@ -39,6 +39,8 @@ class RootView extends Template
       else
         @project.getFilePaths().done (paths) =>
           relativePaths = (path.replace(@project.url, "") for path in paths)
-          @fileFinder = FileFinder.build({urls: relativePaths, selected: (relativePath) => @editor.open(@project.url + relativePath)})
+          @fileFinder = FileFinder.build
+            urls: relativePaths
+            selected: (relativePath) => @editor.open(@project.url + relativePath)
           @addPane(@fileFinder)
           @fileFinder.input.focus()