Add unit tests for libziparchive.

- Add a build rule for host tests
- Add basic tests for Find / Iterate and Extract
  for both deflated & stored entries.
- Fix an off by one error that the test uncovered.

Change-Id: If72009b1ea9791d5a265829f05c32ffe1c2752c4
diff --git a/libziparchive/Android.mk b/libziparchive/Android.mk
index 31c6051..d783747 100644
--- a/libziparchive/Android.mk
+++ b/libziparchive/Android.mk
@@ -51,3 +51,17 @@
 LOCAL_LDFLAGS := -llog
 LOCAL_STATIC_LIBRARIES := libziparchive libz libgtest libgtest_main
 include $(BUILD_NATIVE_TEST)
+
+include $(CLEAR_VARS)
+LOCAL_MODULE := ziparchive-tests-host
+LOCAL_CPP_EXTENSION := .cc
+LOCAL_CFLAGS += \
+    -DGTEST_OS_LINUX \
+    -DGTEST_HAS_STD_STRING
+LOCAL_SRC_FILES := zip_archive_test.cc
+LOCAL_STATIC_LIBRARIES := libziparchive-host \
+	libz \
+	libgtest_host \
+	libgtest_main_host \
+	liblog
+include $(BUILD_HOST_NATIVE_TEST)