Introduce printers for Node and Position for ease of developing GTest test files

Source/core/testing/CoreTestHelpers.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/testing/CoreTestHelpers.h"
+
+#include "core/dom/Document.h"
+#include "core/dom/Range.h"
+#include "core/dom/Text.h"
+#include "core/html/HTMLElement.h"
+#include "wtf/text/StringBuilder.h"
+#include <ios>
+#include <ostream> // NOLINT
+
+namespace blink {
+
+namespace {
+
+// Copied from "dom/Node.cpp".
+void appendAttributeDesc(const Node& node, StringBuilder& stringBuilder, const QualifiedName& name, const char* attrDesc)
+{
+    if (!node.isElementNode())
+        return;
+
+    String attr = toElement(node).getAttribute(name);
+    if (attr.isEmpty())
+        return;
+
+    stringBuilder.append(attrDesc);
+    stringBuilder.appendLiteral("=\"");
+    stringBuilder.append(attr);
+    stringBuilder.appendLiteral("\"");
+}
+
+template <typename PositionType>
+std::ostream& printPosition(std::ostream& ostream, const PositionType& position)
+{
+    if (position.isNull())
+        return ostream << "null";
+    ostream << position.anchorNode() << "@";
+    if (position.anchorType() == PositionType::PositionIsOffsetInAnchor)
+        return ostream << position.offsetInContainerNode();
+    return ostream << static_cast<Position::AnchorType>(position.anchorType());
+}
+
+} // namespace
+
+std::ostream& operator<<(std::ostream& ostream, Position::AnchorType anchorType)
+{
+    switch (anchorType) {
+    case Position::PositionIsAfterAnchor:
+        return ostream << "afterAnchor";
+    case Position::PositionIsAfterChildren:
+        return ostream << "afterChildren";
+    case Position::PositionIsBeforeAnchor:
+        return ostream << "beforeAnchor";
+    case Position::PositionIsBeforeChildren:
+        return ostream << "beforeChildren";
+    case Position::PositionIsOffsetInAnchor:
+        return ostream << "offsetInAnchor";
+    }
+    ASSERT_NOT_REACHED();
+    return ostream << "anchorType=" << static_cast<int>(anchorType);
+}
+
+// |std::ostream| version of |Node::showNode|
+std::ostream& operator<<(std::ostream& ostream, const Node& node)
+{
+    ostream << node.nodeName().utf8().data();
+    if (node.isTextNode())
+        return ostream << " " << node.nodeValue();
+    StringBuilder attrs;
+    appendAttributeDesc(node, attrs, HTMLNames::idAttr, " ID");
+    appendAttributeDesc(node, attrs, HTMLNames::classAttr, " CLASS");
+    appendAttributeDesc(node, attrs, HTMLNames::styleAttr, " STYLE");
+    return ostream << attrs.toString().utf8().data();
+}
+
+std::ostream& operator<<(std::ostream& ostream, const Node* node)
+{
+    if (!node)
+        return ostream << "null";
+    return ostream << *node;
+}
+
+std::ostream& operator<<(std::ostream& ostream, const Position& position)
+{
+    return printPosition(ostream, position);
+}
+
+} // namespace blink