Change ASCII conversion for hash and add tests

Hash was printed using snprintf(), but we can just write yet another hex
conversion utility!

Change-Id: I04f1992deaf5bf1b3e2751c8f07072f8ed6660e9
diff --git a/tests/Android.mk b/tests/Android.mk
new file mode 100644
index 0000000..8ae4b5d
--- /dev/null
+++ b/tests/Android.mk
@@ -0,0 +1,36 @@
+# Build the unit tests.
+LOCAL_PATH := $(call my-dir)
+include $(CLEAR_VARS)
+
+test_src_files := \
+	VolumeManager_test.cpp
+
+shared_libraries := \
+	liblog \
+	libstlport \
+	libcrypto
+
+static_libraries := \
+	libvold \
+	libgtest \
+	libgtest_main
+
+c_includes := \
+	external/openssl/include \
+	bionic \
+	bionic/libstdc++/include \
+	external/gtest/include \
+	external/stlport/stlport
+
+module_tags := eng tests
+
+$(foreach file,$(test_src_files), \
+    $(eval include $(CLEAR_VARS)) \
+    $(eval LOCAL_SHARED_LIBRARIES := $(shared_libraries)) \
+    $(eval LOCAL_STATIC_LIBRARIES := $(static_libraries)) \
+    $(eval LOCAL_C_INCLUDES := $(c_includes)) \
+    $(eval LOCAL_SRC_FILES := $(file)) \
+    $(eval LOCAL_MODULE := $(notdir $(file:%.cpp=%))) \
+    $(eval LOCAL_MODULE_TAGS := $(module_tags)) \
+    $(eval include $(BUILD_EXECUTABLE)) \
+)