Add API tests for NamedDestsByName, DestGetPageIndex.

fpdfsdk/src/fpdfdoc_embeddertest.cpp

+// Copyright 2015 PDFium 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 <limits>
+#include <string>
+
+#include "../../testing/embedder_test.h"
+#include "../../fpdfsdk/include/fpdfview.h"
+#include "../../fpdfsdk/include/fpdfdoc.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+class FPDFDocEmbeddertest : public EmbedderTest {
+};
+
+TEST_F(FPDFDocEmbeddertest, DestGetPageIndex) {
+  EXPECT_TRUE(OpenDocument("testing/resources/named_dests.pdf"));
+
+  // NULL FPDF_DEST case.
+  EXPECT_EQ(0, FPDFDest_GetPageIndex(document(), nullptr));
+
+  // Item from Names array.
+  FPDF_DEST dest = FPDF_GetNamedDestByName(document(), "First");
+  EXPECT_EQ(1, FPDFDest_GetPageIndex(document(), dest));
+
+  // Item from alternate Dests dict.
+  dest = FPDF_GetNamedDestByName(document(), "FirstAlternate");
+  EXPECT_EQ(11, FPDFDest_GetPageIndex(document(), dest));
+}