TEST_MAPPING: test dependers of this crate

Bug: 168167373
Test: TH
Change-Id: I05d260292da408851ad1c3f11798c4d26f617649
diff --git a/TEST_MAPPING b/TEST_MAPPING
new file mode 100644
index 0000000..1e756de
--- /dev/null
+++ b/TEST_MAPPING
@@ -0,0 +1,9 @@
+// Generated by cargo2android.py for tests in Android.bp
+{
+  "presubmit": [
+    {
+      "host": true,
+      "name": "structopt-derive_host_test_src_lib"
+    }
+  ]
+}