Backspace in column 0 below a fold absorbs line into fold

spec/app/edit-session-spec.coffee

@@ -764,6 +764,17 @@ describe "EditSession", ->
             editSession.setCursorScreenPosition(row: 0, column: 0)
             editSession.backspace()
 
+        describe "when the cursor is on the first column of a line below a fold", ->
+          it "absorbs the current line into the fold", ->
+            editSession.setCursorScreenPosition([4,0])
+            editSession.toggleFold()
+            editSession.setCursorScreenPosition([5,0])
+            editSession.backspace()
+
+
+            expect(buffer.lineForRow(7)).toBe "    }    return sort(left).concat(pivot).concat(sort(right));"
+            expect(buffer.lineForRow(8)).toBe "  };"
+
       describe "when there are multiple cursors", ->
         describe "when cursors are on the same line", ->
           it "removes the characters preceding each cursor", ->

src/app/edit-session.coffee

@@ -198,6 +198,9 @@ class EditSession
   destroyFoldsContainingBufferRow: (bufferRow) ->
     @renderer.destroyFoldsContainingBufferRow(bufferRow)
 
+  isFoldedAtScreenRow: (screenRow) ->
+    @screenLineForRow(screenRow).fold?
+
   toggleLineCommentsInRange: (range) ->
     @renderer.toggleLineCommentsInRange(range)
 

src/app/editor.coffee

@@ -341,7 +341,7 @@ class Editor extends View
     @screenLineCount() - 1
 
   isFoldedAtScreenRow: (screenRow) ->
-    @screenLineForRow(screenRow).fold?
+    @activeEditSession.isFoldedAtScreenRow(screenRow)
 
   destroyFoldsContainingBufferRow: (bufferRow) ->
     @renderer.destroyFoldsContainingBufferRow(bufferRow)

src/app/selection.coffee

@@ -86,6 +86,9 @@ class Selection
   selectToScreenPosition: (position) ->
     @modifySelection => @cursor.setScreenPosition(position)
 
+  selectToBufferPosition: (position) ->
+    @modifySelection => @cursor.setBufferPosition(position)
+
   selectRight: ->
     @modifySelection => @cursor.moveRight()
 
@@ -131,7 +134,13 @@ class Selection
 
   backspace: ->
     @editSession.destroyFoldsContainingBufferRow(@getBufferRange().end.row)
-    @selectLeft() if @isEmpty()
+
+    if @isEmpty()
+      if @editSession.isFoldedAtScreenRow(@cursor.getCurrentScreenRow() - 1)
+        @selectToBufferPosition([@cursor.getCurrentBufferRow() - 1, Infinity])
+      else
+        @selectLeft()
+
     @deleteSelectedText()
 
   backspaceToBeginningOfWord: ->