diff --git a/TEST_MAPPING b/TEST_MAPPING
new file mode 100644
index 0000000..0c98c27
--- /dev/null
+++ b/TEST_MAPPING
@@ -0,0 +1,9 @@
+{
+  "presubmit": [
+    // recovery_host_test (imgdiff) relies on zlib for patch generation.
+    {
+      "name": "recovery_host_test",
+      "host": true
+    }
+  ]
+}