Dom text scanner fixes (#505)

* Fix test case

* Add test-dom-text-scanner

* Ensure that DOMTextScanner._node never becomes null

* Add remainder

2 files changed, 5 insertions, 3 deletions

diff --git a/test/data/html/test-dom-text-scanner.html b/test/data/html/test-dom-text-scanner.html
index 6b78570a..dc06eb64 100644
--- a/test/data/html/test-dom-text-scanner.html
+++ b/test/data/html/test-dom-text-scanner.html
@@ -85,7 +85,7 @@
             "expected": {
                 "node": "span:nth-of-type(2)::text",
                 "offset": 6,
-                "content": "小ぢんまり1\n小ぢんまり2"
+                "content": "小ぢんまり1 小ぢんまり2"
             }
         }'
     >
diff --git a/test/test-dom-text-scanner.js b/test/test-dom-text-scanner.js
index 41d6e307..7374ff87 100644
--- a/test/test-dom-text-scanner.js
+++ b/test/test-dom-text-scanner.js
@@ -103,7 +103,8 @@ async function testDomTextScanner(dom, {DOMTextScanner}) {
                 expected: {
                     node: expectedNode,
                     offset: expectedOffset,
-                    content: expectedContent
+                    content: expectedContent,
+                    remainder: expectedRemainder
                 }
             } = testDataItem;
 
@@ -115,10 +116,11 @@ async function testDomTextScanner(dom, {DOMTextScanner}) {
                 const scanner = new DOMTextScanner(node, offset, forcePreserveWhitespace, generateLayoutContent);
                 scanner.seek(length);
 
-                const {node: actualNode1, offset: actualOffset1, content: actualContent1} = scanner;
+                const {node: actualNode1, offset: actualOffset1, content: actualContent1, remainder: actualRemainder1} = scanner;
                 assert.strictEqual(actualContent1, expectedContent);
                 assert.strictEqual(actualOffset1, expectedOffset);
                 assert.strictEqual(actualNode1, expectedNode);
+                assert.strictEqual(actualRemainder1, expectedRemainder || 0);
             }
 
             // Substring tests