support jquery style element / css style / id lookups of elements on a document/element - along with test cases

testlib/test/dom/DomBuilderTest.kt

@@ -20,8 +20,10 @@ class DomBuilderTest() : TestSupport() {
             style = "bold"
             cssClass = "bar"
             addElement("child") {
+                id = "id2"
                 cssClass = "another"
                 addElement("grandChild") {
+                    id = "id3"
                     cssClass = "tiny"
                     addText("Hello World!")
                 // TODO support neater syntax sugar for adding text?
@@ -31,6 +33,51 @@ class DomBuilderTest() : TestSupport() {
         }
         println("builder document: ${doc.toXmlString()}")
 
+
+        // test css selections on document
+        assertEquals(0, doc[".doesNotExist"].size())
+        assertEquals(1, doc[".another"].size())
+        assertEquals(1, doc[".tiny"].size())
+        assertEquals(1, doc[".bar"].size())
+
+        // element tag selections
+        assertEquals(0, doc["doesNotExist"].size())
+        assertEquals(1, doc["foo"].size())
+        assertEquals(1, doc["child"].size())
+        assertEquals(1, doc["grandChild"].size())
+
+        // id selections
+        assertEquals(1, doc["#id1"].size())
+        assertEquals(1, doc["#id2"].size())
+        assertEquals(1, doc["#id3"].size())
+
+        val root = doc.rootElement
+        if (root != null) {
+            assert {
+                root.hasClass("bar")
+            }
+
+            // test css selections on element
+            assertEquals(0, root[".doesNotExist"].size())
+            assertEquals(1, root[".another"].size())
+            assertEquals(1, root[".tiny"].size())
+            assertEquals(0, root[".bar"].size())
+
+            // element tag selections
+            assertEquals(0, root["doesNotExist"].size())
+            assertEquals(0, root["foo"].size())
+            assertEquals(1, root["child"].size())
+            assertEquals(1, root["grandChild"].size())
+
+            // id selections
+            assertEquals(1, root["#id1"].size())
+            assertEquals(1, root["#id2"].size())
+            assertEquals(1, root["#id3"].size())
+        } else {
+            fail("No root!")
+        }
+
+
         val grandChild = doc["grandChild"].first
         if (grandChild != null) {
             println("got element ${grandChild.toXmlString()} with text '${grandChild.text}`")