Make default link text the link title

the placeholder text should always be the current
link's title and saving with no text entered should
default to the current link's title

closes LF-343
flag=rce_ux_improvements

test plan:
- have an rce open with the flag on, add a course link
  to your page.
- open the course link options tray. Change the text to
  something else, remove the text, and ensure the placeholder
  is still the title of the current link
- change the current link to a different course link using the
  tray
- delete the text and ensure placeholder is the new link
- click replace and make sure the text is the new link's title

Change-Id: I99e0600600732f59670911520688dd5f4a9913c5
Reviewed-on: https://gerrit.instructure.com/c/canvas-lms/+/319776
Tested-by: Service Cloud Jenkins <svc.cloudjenkins@instructure.com>
Reviewed-by: Jackson Howe <jackson.howe@instructure.com>
QA-Review: Jackson Howe <jackson.howe@instructure.com>
Product-Review: Sarah Gerard <sarah.gerard@instructure.com>

packages/canvas-rce/src/rce/plugins/shared/CanvasContentTray.js

@@ -289,7 +289,7 @@ export default function CanvasContentTray(props) {
             published,
           })
           setLinkText(text)
-          setPlaceholderText(text)
+          setPlaceholderText(fileName)
         } else {
           setIsEditTray(false)
         }
@@ -371,7 +371,7 @@ export default function CanvasContentTray(props) {
     const newLink = {
       ...link,
       forceRename: true,
-      text: linkText || placeholderText,
+      text: linkText,
     }
 
     bridge.insertLink(newLink)
@@ -490,7 +490,7 @@ export default function CanvasContentTray(props) {
               <LinkDisplay
                 linkText={linkText}
                 Icon={Icon}
-                placeholderText={placeholderText}
+                placeholderText={link?.title || placeholderText}
                 linkFileName={link?.title || ''}
                 published={link?.published || false}
                 handleTextChange={setLinkText}

packages/canvas-rce/src/rce/plugins/shared/__tests__/CanvasContentTray.test.js

@@ -24,6 +24,7 @@ import * as fakeSource from '../../../../rcs/fake'
 import initialState from '../../../../sidebar/store/initialState'
 import sidebarHandlers from '../../../../sidebar/containers/sidebarHandlers'
 import CanvasContentTray from '../CanvasContentTray'
+import {LinkDisplay} from '../LinkDisplay'
 
 jest.useFakeTimers()
 jest.mock('../../../../canvasFileBrowser/FileBrowser', () => {
@@ -43,6 +44,9 @@ jest.mock('../../../../bridge', () => {
   original.default.insertLink = jest.fn()
   return original
 })
+jest.mock('../LinkDisplay', () => ({
+  LinkDisplay: jest.fn(() => <div data-testid="LinkDisplay" />),
+}))
 
 const storeInitialState = {
   ...initialState({
@@ -148,6 +152,17 @@ describe('RCE Plugins > CanvasContentTray', () => {
         })
       })
     })
+
+    it('sets placeholder to the current link title', async () => {
+      renderComponent()
+      await showTrayForPlugin('course_link_edit')
+      await waitFor(() => {
+        expect(LinkDisplay).toHaveBeenCalledWith(
+          expect.objectContaining({placeholderText: 'some filename'}),
+          {}
+        )
+      })
+    })
   })
 
   describe('Tray Label in course context', () => {