Never cast Attr to ContainerNode based on nodeType ATTRIBUTE_NODE

Source/core/dom/AttrTest.cpp

+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "config.h"
+#include "core/dom/Attr.h"
+
+#include "core/dom/Document.h"
+#include <gmock/gmock.h>
+#include <gtest/gtest.h>
+
+using namespace blink;
+
+namespace {
+
+class AttrTest : public ::testing::Test {
+protected:
+    virtual void SetUp() override;
+
+    PassRefPtrWillBeRawPtr<Attr> createAttribute();
+    const AtomicString& value() const { return m_value; }
+
+private:
+    RefPtrWillBePersistent<Document> m_document;
+    AtomicString m_value;
+};
+
+void AttrTest::SetUp()
+{
+    m_document = Document::create();
+    m_value = "value";
+}
+
+PassRefPtrWillBeRawPtr<Attr> AttrTest::createAttribute()
+{
+    return m_document->createAttribute("name", ASSERT_NO_EXCEPTION);
+}
+
+TEST_F(AttrTest, InitialValueState)
+{
+    RefPtrWillBeRawPtr<Attr> attr = createAttribute();
+    EXPECT_EQ(emptyAtom, attr->value());
+    EXPECT_EQ(emptyString(), attr->toNode()->nodeValue());
+    EXPECT_EQ(String(), attr->textContent());
+}
+
+TEST_F(AttrTest, SetValue)
+{
+    RefPtrWillBeRawPtr<Attr> attr = createAttribute();
+    attr->setValue(value());
+    EXPECT_EQ(value(), attr->value());
+    EXPECT_EQ(value(), attr->toNode()->nodeValue());
+    // Node::textContent() always returns String() for Attr.
+    EXPECT_EQ(String(), attr->textContent());
+}
+
+TEST_F(AttrTest, SetNodeValue)
+{
+    RefPtrWillBeRawPtr<Attr> attr = createAttribute();
+    attr->toNode()->setNodeValue(value());
+    EXPECT_EQ(value(), attr->value());
+    EXPECT_EQ(value(), attr->toNode()->nodeValue());
+    // Node::textContent() always returns String() for Attr.
+    EXPECT_EQ(String(), attr->textContent());
+}
+
+TEST_F(AttrTest, SetTextContent)
+{
+    RefPtrWillBeRawPtr<Attr> attr = createAttribute();
+    // Node::setTextContent() does nothing for Attr.
+    attr->setTextContent(value());
+    EXPECT_EQ(emptyAtom, attr->value());
+    EXPECT_EQ(emptyString(), attr->toNode()->nodeValue());
+    EXPECT_EQ(String(), attr->textContent());
+}
+
+TEST_F(AttrTest, LengthOfContents)
+{
+    RefPtrWillBeRawPtr<Attr> attr = createAttribute();
+    EXPECT_EQ(0u, attr->lengthOfContents());
+    attr->setValue(value());
+    EXPECT_EQ(0u, attr->lengthOfContents());
+}
+
+} // unnamed namespace