Fix missing PDF highlights

fda63b4 unfortunately broke highlighting in PDFs, because the PDF
anchoring code first finds the text in the document, and then uses a
TextPositionSelector and the HTML anchoring code to select a range in
the rendered page for highlighting.

This commit fixes that issue by moving the TextQuoteSelector check up a
level into `Guest#anchor`.

I've added two tests for this in `guest-test.coffee` -- one tests that
annotations where the target contains no TextQuoteSelector are marked as
orphans, and the second tests that the low-level anchoring code is never
called in this case.

I have also removed the integration test, on the basis that I don't
think integration testing failure cases is a good habit to get into.

Fixes #3530.

h/static/scripts/annotator/anchoring/html.coffee

@@ -50,11 +50,6 @@ exports.anchor = (root, selectors, options = {}) ->
       when 'RangeSelector'
         range = selector
 
-  # Assert that there is a quote selector, since otherwise we cannot validate
-  # the rest of the annotation's selectors.
-  if not quote?
-    return Promise.reject(new Error('quote selector not found'))
-
   # Assert the quote matches the stored quote, if applicable
   maybeAssertQuote = (range) ->
     if quote?.exact? and range.toString() != quote.exact

h/static/scripts/annotator/guest.coffee

@@ -187,6 +187,15 @@ module.exports = class Guest extends Annotator
     annotation.target ?= []
 
     locate = (target) ->
+      # Check that the anchor has a TextQuoteSelector -- without a
+      # TextQuoteSelector we have no basis on which to verify that we have
+      # reanchored correctly and so we shouldn't even try.
+      #
+      # Returning an anchor without a range will result in this annotation being
+      # treated as an orphan (assuming no other targets anchor).
+      if not (target.selector ? []).some((s) => s.type == 'TextQuoteSelector')
+        return Promise.resolve({annotation, target})
+
       # Find a target using the anchoring module.
       options = {
         cache: self.anchoringCache

h/static/scripts/annotator/test/guest-test.coffee

@@ -341,7 +341,11 @@ describe 'Guest', ->
 
     it "doesn't mark an annotation in which the target anchors as an orphan", ->
       guest = createGuest()
-      annotation = {target: [{selector: []}]}
+      annotation = {
+        target: [
+          {selector: [{type: 'TextQuoteSelector', exact: 'hello'}]},
+        ]
+      }
       sandbox.stub(anchoring, 'anchor').returns(Promise.resolve(range))
 
       guest.anchor(annotation).then ->
@@ -349,7 +353,12 @@ describe 'Guest', ->
 
     it "doesn't mark an annotation in which at least one target anchors as an orphan", ->
       guest = createGuest()
-      annotation = {target: [{selector: []}, {selector: []}]}
+      annotation = {
+        target: [
+          {selector: [{type: 'TextQuoteSelector', exact: 'notinhere'}]},
+          {selector: [{type: 'TextQuoteSelector', exact: 'hello'}]},
+        ]
+      }
       sandbox.stub(anchoring, 'anchor')
         .onFirstCall().returns(Promise.reject())
         .onSecondCall().returns(Promise.resolve(range))
@@ -359,7 +368,11 @@ describe 'Guest', ->
 
     it "marks an annotation in which the target fails to anchor as an orphan", ->
       guest = createGuest()
-      annotation = target: [{selector: []}]
+      annotation = {
+        target: [
+          {selector: [{type: 'TextQuoteSelector', exact: 'notinhere'}]},
+        ]
+      }
       sandbox.stub(anchoring, 'anchor').returns(Promise.reject())
 
       guest.anchor(annotation).then ->
@@ -367,12 +380,43 @@ describe 'Guest', ->
 
     it "marks an annotation in which all (suitable) targets fail to anchor as an orphan", ->
       guest = createGuest()
-      annotation = target: [{selector: []}, {selector: []}]
+      annotation = {
+        target: [
+          {selector: [{type: 'TextQuoteSelector', exact: 'notinhere'}]},
+          {selector: [{type: 'TextQuoteSelector', exact: 'neitherami'}]},
+        ]
+      }
       sandbox.stub(anchoring, 'anchor').returns(Promise.reject())
 
       guest.anchor(annotation).then ->
         assert.isTrue(annotation.$orphan)
 
+    it "marks an annotation where the target has no TextQuoteSelectors as an orphan", ->
+      guest = createGuest()
+      annotation = {
+        target: [
+          {selector: [{type: 'TextPositionSelector', start: 0, end: 5}]},
+        ]
+      }
+      # This shouldn't be called, but if it is, we successfully anchor so that
+      # this test is guaranteed to fail.
+      sandbox.stub(anchoring, 'anchor').returns(Promise.resolve(range))
+
+      guest.anchor(annotation).then ->
+        assert.isTrue(annotation.$orphan)
+
+    it "does not attempt to anchor targets which have no TextQuoteSelector", ->
+      guest = createGuest()
+      annotation = {
+        target: [
+          {selector: [{type: 'TextPositionSelector', start: 0, end: 5}]},
+        ]
+      }
+      sandbox.spy(anchoring, 'anchor')
+
+      guest.anchor(annotation).then ->
+        assert.notCalled(anchoring.anchor)
+
     it 'updates the cross frame and bucket bar plugins', (done) ->
       guest = createGuest()
       guest.plugins.CrossFrame =
@@ -390,7 +434,7 @@ describe 'Guest', ->
       highlights = [document.createElement('span')]
       sandbox.stub(anchoring, 'anchor').returns(Promise.resolve(range))
       sandbox.stub(highlighter, 'highlightRange').returns(highlights)
-      target = [{selector: []}]
+      target = {selector: [{type: 'TextQuoteSelector', exact: 'hello'}]}
       guest.anchor({target: [target]}).then (anchors) ->
         assert.equal(anchors.length, 1)
       .then(done, done)
@@ -400,7 +444,7 @@ describe 'Guest', ->
       highlights = [document.createElement('span')]
       sandbox.stub(anchoring, 'anchor').returns(Promise.resolve(range))
       sandbox.stub(highlighter, 'highlightRange').returns(highlights)
-      target = [{selector: []}]
+      target = {selector: [{type: 'TextQuoteSelector', exact: 'hello'}]}
       annotation = {target: [target]}
       guest.anchor(annotation).then ->
         assert.equal(guest.anchors.length, 1)
@@ -426,7 +470,7 @@ describe 'Guest', ->
 
     it 'does not reanchor targets that are already anchored', (done) ->
       guest = createGuest()
-      annotation = target: [{selector: "test"}]
+      annotation = target: [{selector: [{type: 'TextQuoteSelector', exact: 'hello'}]}]
       stub = sandbox.stub(anchoring, 'anchor').returns(Promise.resolve(range))
       guest.anchor(annotation).then ->
         guest.anchor(annotation).then ->

h/static/scripts/annotator/test/integration/anchoring-test.js

@@ -99,22 +99,4 @@ describe('anchoring', function () {
     ],
     expectFail: true,
   }]);
-
-  unroll('should silently fail when an annotation does not have a quote selector', function (testCase) {
-    var annotation = testCase.annotation;
-    var anchored = guest.anchor(annotation);
-
-    return anchored.then(function (result) {
-      assert.deepEqual(result, []);
-    });
-  }, [{
-    annotation: [{
-      target: [{
-        selector: [{
-          type: 'FragmentSelector',
-          value: 't=30,60'
-        }]
-      }]
-    }],
-  }]);
 });