AAPT2: Better debugging output

Test: make aapt2_tests
Change-Id: I7778b773201381538dc1f2e376abee4eb33e44c0
diff --git a/tools/aapt2/text/Printer_test.cpp b/tools/aapt2/text/Printer_test.cpp
new file mode 100644
index 0000000..58beae7
--- /dev/null
+++ b/tools/aapt2/text/Printer_test.cpp
@@ -0,0 +1,67 @@
+/*
+ * Copyright (C) 2017 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "text/Printer.h"
+
+#include "io/StringStream.h"
+#include "test/Test.h"
+
+using ::aapt::io::StringOutputStream;
+using ::android::StringPiece;
+using ::testing::StrEq;
+
+namespace aapt {
+namespace text {
+
+TEST(PrinterTest, PrintsToStreamWithIndents) {
+  std::string result;
+  StringOutputStream out(&result);
+  Printer printer(&out);
+
+  printer.Print("Hello");
+  out.Flush();
+  EXPECT_THAT(result, StrEq("Hello"));
+
+  printer.Println();
+  out.Flush();
+  EXPECT_THAT(result, StrEq("Hello\n"));
+
+  // This shouldn't print anything yet.
+  printer.Indent();
+  out.Flush();
+  EXPECT_THAT(result, StrEq("Hello\n"));
+
+  // Now we should see the indent.
+  printer.Print("world!");
+  out.Flush();
+  EXPECT_THAT(result, StrEq("Hello\n  world!"));
+
+  printer.Println(" What a\nlovely day.");
+  out.Flush();
+  EXPECT_THAT(result, StrEq("Hello\n  world! What a\n  lovely day.\n"));
+
+  // This shouldn't print anything yet.
+  printer.Undent();
+  out.Flush();
+  EXPECT_THAT(result, StrEq("Hello\n  world! What a\n  lovely day.\n"));
+
+  printer.Println("Isn't it?");
+  out.Flush();
+  EXPECT_THAT(result, StrEq("Hello\n  world! What a\n  lovely day.\nIsn't it?\n"));
+}
+
+}  // namespace text
+}  // namespace aapt