Add more clap tests.

Bug: 260823636
Test: atest compos_verify.test fd_server.test initrd_bootconfig.test composd_cmd.test
Change-Id: I7fe3fbf5b8c349618ccdef2f096b77737eabed42
diff --git a/authfs/TEST_MAPPING b/authfs/TEST_MAPPING
index 5e144c7..450f133 100644
--- a/authfs/TEST_MAPPING
+++ b/authfs/TEST_MAPPING
@@ -4,6 +4,9 @@
       "name": "authfs_device_test_src_lib"
     },
     {
+      "name": "fd_server.test"
+    },
+    {
       "name": "open_then_run.test"
     },
     {
diff --git a/authfs/fd_server/Android.bp b/authfs/fd_server/Android.bp
index 44407a2..f7cb5e3 100644
--- a/authfs/fd_server/Android.bp
+++ b/authfs/fd_server/Android.bp
@@ -23,3 +23,25 @@
     ],
     apex_available: ["com.android.virt"],
 }
+
+rust_test {
+    name: "fd_server.test",
+    srcs: ["src/main.rs"],
+    rustlibs: [
+        "authfs_aidl_interface-rust",
+        "libandroid_logger",
+        "libanyhow",
+        "libauthfs_fsverity_metadata",
+        "libbinder_rs",
+        "libclap",
+        "liblibc",
+        "liblog_rust",
+        "libnix",
+        "librpcbinder_rs",
+    ],
+    prefer_rlib: true,
+    shared_libs: [
+        "libbinder_rpc_unstable",
+    ],
+    test_suites: ["general-tests"],
+}
diff --git a/authfs/fd_server/src/main.rs b/authfs/fd_server/src/main.rs
index 9d97423..f91ebec 100644
--- a/authfs/fd_server/src/main.rs
+++ b/authfs/fd_server/src/main.rs
@@ -148,3 +148,15 @@
     server.join();
     Ok(())
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use clap::CommandFactory;
+
+    #[test]
+    fn verify_args() {
+        // Check that the command parsing has been configured in a valid way.
+        Args::command().debug_assert();
+    }
+}