Add conversion methods to hidl_string and hidl_vec

Add unit test for libhidl.

Test: mma
Test: make libhidl-test

Bug: 30471989
Bug: 31982575

Change-Id: Ic7d73a10e5cc178786c628e18d3659400b1afb92
diff --git a/test/Android.bp b/test/Android.bp
new file mode 100644
index 0000000..b645f59
--- /dev/null
+++ b/test/Android.bp
@@ -0,0 +1,19 @@
+cc_test {
+    name: "libhidl-test",
+    gtest: false,
+    srcs: ["main.cpp"],
+
+    shared_libs: [
+        "libbase",
+        "libhidl",
+        "libhwbinder",
+        "liblog",
+        "libutils",
+    ],
+    static_libs: ["libgtest"],
+
+    cflags: [
+        "-O0",
+        "-g",
+    ],
+}