Port .selectLinesContainingCursors() specs

spec/text-editor-component-spec.coffee

@@ -3393,6 +3393,19 @@ describe "TextEditorComponent", ->
     afterEach ->
       atom.themes.removeStylesheet("test")
 
+    describe "when selecting lines containing cursors", ->
+      it "autoscrolls to the selection", ->
+        editor.setCursorScreenPosition([5, 6])
+        nextAnimationFrame()
+
+        wrapperNode.scrollToTop()
+        nextAnimationFrame()
+        expect(wrapperNode.getScrollTop()).toBe 0
+
+        editor.selectLinesContainingCursors()
+        nextAnimationFrame()
+        expect(wrapperNode.getScrollBottom()).toBe (7 + editor.getVerticalScrollMargin()) * 10
+
     describe "moving cursors", ->
       it "scrolls down when the last cursor gets closer than ::verticalScrollMargin to the bottom of the editor", ->
         expect(wrapperNode.getScrollTop()).toBe 0

spec/text-editor-spec.coffee

@@ -1194,20 +1194,6 @@ describe "TextEditor", ->
           editor.selectLinesContainingCursors()
           expect(editor.getSelectedBufferRange()).toEqual [[1, 0], [4, 0]]
 
-      it "autoscrolls to the selection", ->
-        editor.setLineHeightInPixels(10)
-        editor.setDefaultCharWidth(10)
-        editor.setHeight(50)
-        editor.setWidth(50)
-        editor.setHorizontalScrollbarHeight(0)
-        editor.setCursorScreenPosition([5, 6])
-
-        editor.scrollToTop()
-        expect(editor.getScrollTop()).toBe 0
-
-        editor.selectLinesContainingCursors()
-        expect(editor.getScrollBottom()).toBe (7 + editor.getVerticalScrollMargin()) * 10
-
     describe ".selectToBeginningOfWord()", ->
       it "selects text from cusor position to beginning of word", ->
         editor.setCursorScreenPosition [0, 13]

src/text-editor-element.coffee

@@ -231,6 +231,12 @@ class TextEditorElement extends HTMLElement
   setScrollBottom: (scrollBottom) ->
     @component.setScrollBottom(scrollBottom)
 
+  scrollToTop: ->
+    @setScrollTop(0)
+
+  scrollToBottom: ->
+    @setScrollBottom(Infinity)
+
   getScrollTop: ->
     @component.getScrollTop()