Add innerHTML attribute support to HtmlUnitDriver

Signed-off-by: Luke Inman-Semerau <luke.semerau@gmail.com>

Author: Toilal

java/client/src/org/openqa/selenium/htmlunit/HtmlUnitWebElement.java

@@ -418,6 +418,10 @@ public String getAttribute(String name) {
       return element.getTextContent();
     }
 
+    if ("innerHTML".equalsIgnoreCase(lowerName)) {
+      return element.asXml();
+    }
+
     if ("value".equals(lowerName)) {
       if (element instanceof HtmlTextArea) {
         return ((HtmlTextArea) element).getText();

java/client/test/org/openqa/selenium/ElementAttributeTest.java

@@ -26,6 +26,7 @@
 import java.util.List;
 
 import static org.hamcrest.Matchers.anyOf;
+import static org.hamcrest.Matchers.containsString;
 import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.Matchers.is;
 import static org.hamcrest.Matchers.nullValue;
@@ -226,6 +227,14 @@ public void testShouldReturnTheContentsOfATextAreaAsItsValue() {
     assertThat(value, equalTo("Example text"));
   }
 
+  @Test
+  public void testShouldReturnInnerHtml() {
+    driver.get(pages.simpleTestPage);
+
+    String html = driver.findElement(By.id("wrappingtext")).getAttribute("innerHTML");
+    assertThat(html, containsString("<tbody>"));
+  }
+
   @Test
   public void testShouldTreatReadonlyAsAValue() {
     driver.get(pages.formPage);