diff --git a/authfs/tests/Android.bp b/authfs/tests/Android.bp
index 8061c56..fd45e13 100644
--- a/authfs/tests/Android.bp
+++ b/authfs/tests/Android.bp
@@ -14,8 +14,26 @@
         "VirtualizationTestHelper",
     ],
     test_suites: ["general-tests"],
+    target_required: ["open_then_run"],
     data: [
         ":authfs_test_files",
         ":MicrodroidTestApp.signed",
     ],
 }
+
+rust_test {
+    name: "open_then_run",
+    crate_name: "open_then_run",
+    srcs: ["open_then_run.rs"],
+    edition: "2018",
+    rustlibs: [
+        "libandroid_logger",
+        "libanyhow",
+        "libclap",
+        "libcommand_fds",
+        "liblog_rust",
+        "libnix",
+    ],
+    test_suites: ["general-tests"],
+    test_harness: false,
+}
diff --git a/authfs/tests/AndroidTest.xml b/authfs/tests/AndroidTest.xml
index 6100ab9..9deab5b 100644
--- a/authfs/tests/AndroidTest.xml
+++ b/authfs/tests/AndroidTest.xml
@@ -31,6 +31,11 @@
     <target_preparer class="com.android.tradefed.targetprep.PushFilePreparer">
         <option name="cleanup" value="true" />
         <option name="abort-on-push-failure" value="true" />
+
+        <!-- Test executable -->
+        <option name="push-file" key="open_then_run" value="/data/local/tmp/authfs/open_then_run" />
+
+        <!-- Test data files -->
         <option name="push-file" key="cert.der" value="/data/local/tmp/authfs/cert.der" />
         <option name="push-file" key="input.4m" value="/data/local/tmp/authfs/input.4m" />
         <option name="push-file" key="input.4k1" value="/data/local/tmp/authfs/input.4k1" />
diff --git a/authfs/tests/java/src/com/android/fs/AuthFsHostTest.java b/authfs/tests/java/src/com/android/fs/AuthFsHostTest.java
index f06c8f5..2d518a0 100644
--- a/authfs/tests/java/src/com/android/fs/AuthFsHostTest.java
+++ b/authfs/tests/java/src/com/android/fs/AuthFsHostTest.java
@@ -75,6 +75,7 @@
     private static boolean sAssumptionFailed;
 
     private ExecutorService mThreadPool = Executors.newCachedThreadPool();
+    private String mAbi;
 
     @BeforeClassWithInfo
     public static void beforeClassWithDevice(TestInformation testInfo)
@@ -138,6 +139,7 @@
     @Before
     public void setUp() {
         assumeFalse(sAssumptionFailed);
+        mAbi = getAbi().getName();
     }
 
     @After
@@ -154,7 +156,8 @@
             throws DeviceNotAvailableException, InterruptedException {
         // Setup
         runFdServerOnAndroid(
-                "3<input.4m 4<input.4m.merkle_dump 5<input.4m.fsv_sig 6<input.4m",
+                "--open-ro 3:input.4m --open-ro 4:input.4m.merkle_dump --open-ro 5:input.4m.fsv_sig"
+                        + " --open-ro 6:input.4m",
                 "--ro-fds 3:4:5 --ro-fds 6");
 
         runAuthFsOnMicrodroid(
@@ -179,8 +182,9 @@
             throws DeviceNotAvailableException, InterruptedException {
         // Setup
         runFdServerOnAndroid(
-                "3<input.4k 4<input.4k.merkle_dump 5<input.4k.fsv_sig"
-                        + " 6<input.4k1 7<input.4k1.merkle_dump 8<input.4k1.fsv_sig",
+                "--open-ro 3:input.4k --open-ro 4:input.4k.merkle_dump --open-ro"
+                    + " 5:input.4k.fsv_sig --open-ro 6:input.4k1 --open-ro 7:input.4k1.merkle_dump"
+                    + " --open-ro 8:input.4k1.fsv_sig",
                 "--ro-fds 3:4:5 --ro-fds 6:7:8");
         runAuthFsOnMicrodroid(
                 "--remote-ro-file 10:3:cert.der --remote-ro-file 11:6:cert.der --cid "
@@ -203,7 +207,9 @@
             throws DeviceNotAvailableException, InterruptedException {
         // Setup
         runFdServerOnAndroid(
-                "3<input.4m 4<input.4m.merkle_dump.bad 5<input.4m.fsv_sig", "--ro-fds 3:4:5");
+                "--open-ro 3:input.4m --open-ro 4:input.4m.merkle_dump.bad "
+                        + "--open-ro 5:input.4m.fsv_sig",
+                "--ro-fds 3:4:5");
         runAuthFsOnMicrodroid("--remote-ro-file 10:3:cert.der --cid " + VMADDR_CID_HOST);
 
         // Verify
@@ -214,7 +220,7 @@
     public void testWriteThroughCorrectly()
             throws DeviceNotAvailableException, InterruptedException {
         // Setup
-        runFdServerOnAndroid("3<>output", "--rw-fds 3");
+        runFdServerOnAndroid("--open-rw 3:output", "--rw-fds 3");
         runAuthFsOnMicrodroid("--remote-new-rw-file 20:3 --cid " + VMADDR_CID_HOST);
 
         // Action
@@ -232,7 +238,7 @@
     public void testWriteFailedIfDetectsTampering()
             throws DeviceNotAvailableException, InterruptedException {
         // Setup
-        runFdServerOnAndroid("3<>output", "--rw-fds 3");
+        runFdServerOnAndroid("--open-rw 3:output", "--rw-fds 3");
         runAuthFsOnMicrodroid("--remote-new-rw-file 20:3 --cid " + VMADDR_CID_HOST);
 
         String srcPath = "/system/bin/linker64";
@@ -263,7 +269,7 @@
     @Test
     public void testFileResize() throws DeviceNotAvailableException, InterruptedException {
         // Setup
-        runFdServerOnAndroid("3<>output", "--rw-fds 3");
+        runFdServerOnAndroid("--open-rw 3:output", "--rw-fds 3");
         runAuthFsOnMicrodroid("--remote-new-rw-file 20:3 --cid " + VMADDR_CID_HOST);
         String outputPath = MOUNT_DIR + "/20";
         String backendPath = TEST_DIR + "/output";
@@ -367,10 +373,25 @@
         }
     }
 
-    private void runFdServerOnAndroid(String execParamsForOpeningFds, String flags)
+    private String getOpenThenRunPath() {
+        // Construct path to match PushFilePreparer's upload path.
+        return TEST_DIR + "/open_then_run/" + mAbi + "/open_then_run";
+    }
+
+    private void runFdServerOnAndroid(String helperFlags, String fdServerFlags)
             throws DeviceNotAvailableException {
-        String cmd = "cd " + TEST_DIR + " && exec " + execParamsForOpeningFds + " " + FD_SERVER_BIN
-                + " " + flags;
+        String cmd =
+                "cd "
+                        + TEST_DIR
+                        + " && "
+                        + getOpenThenRunPath()
+                        + " "
+                        + helperFlags
+                        + " -- "
+                        + FD_SERVER_BIN
+                        + " "
+                        + fdServerFlags;
+
         mThreadPool.submit(
                 () -> {
                     try {
diff --git a/authfs/tests/open_then_run.rs b/authfs/tests/open_then_run.rs
new file mode 100644
index 0000000..ba3ed38
--- /dev/null
+++ b/authfs/tests/open_then_run.rs
@@ -0,0 +1,159 @@
+/*
+ * Copyright (C) 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+//! This is a test helper program that opens files and/or directories, then passes the file
+//! descriptors to the specified command. When passing the file descriptors, they are mapped to the
+//! specified numbers in the child process.
+
+use anyhow::{bail, Context, Result};
+use clap::{App, Arg, Values};
+use command_fds::{CommandFdExt, FdMapping};
+use log::{debug, error};
+use nix::{dir::Dir, fcntl::OFlag, sys::stat::Mode};
+use std::fs::{File, OpenOptions};
+use std::os::unix::io::{AsRawFd, RawFd};
+use std::process::Command;
+
+// `PseudoRawFd` is just an integer and not necessarily backed by a real FD. It is used to denote
+// the expecting FD number, when trying to set up FD mapping in the child process. The intention
+// with this alias is to improve readability by distinguishing from actual RawFd.
+type PseudoRawFd = RawFd;
+
+struct FileMapping<T: AsRawFd> {
+    file: T,
+    target_fd: PseudoRawFd,
+}
+
+impl<T: AsRawFd> FileMapping<T> {
+    fn as_fd_mapping(&self) -> FdMapping {
+        FdMapping { parent_fd: self.file.as_raw_fd(), child_fd: self.target_fd }
+    }
+}
+
+struct Args {
+    ro_files: Vec<FileMapping<File>>,
+    rw_files: Vec<FileMapping<File>>,
+    dir_files: Vec<FileMapping<Dir>>,
+    cmdline_args: Vec<String>,
+}
+
+fn parse_and_create_file_mapping<F, T>(
+    values: Option<Values<'_>>,
+    opener: F,
+) -> Result<Vec<FileMapping<T>>>
+where
+    F: Fn(&str) -> Result<T>,
+    T: AsRawFd,
+{
+    if let Some(options) = values {
+        options
+            .map(|option| {
+                // Example option: 10:/some/path
+                let strs: Vec<&str> = option.split(':').collect();
+                if strs.len() != 2 {
+                    bail!("Invalid option: {}", option);
+                }
+                let fd = strs[0].parse::<PseudoRawFd>().context("Invalid FD format")?;
+                let path = strs[1];
+                Ok(FileMapping { target_fd: fd, file: opener(path)? })
+            })
+            .collect::<Result<_>>()
+    } else {
+        Ok(Vec::new())
+    }
+}
+
+fn parse_args() -> Result<Args> {
+    #[rustfmt::skip]
+    let matches = App::new("open_then_run")
+        .arg(Arg::with_name("open-ro")
+             .long("open-ro")
+             .value_name("FD:PATH")
+             .help("Open <PATH> read-only to pass as fd <FD>")
+             .multiple(true)
+             .number_of_values(1))
+        .arg(Arg::with_name("open-rw")
+             .long("open-rw")
+             .value_name("FD:PATH")
+             .help("Open/create <PATH> read-write to pass as fd <FD>")
+             .multiple(true)
+             .number_of_values(1))
+        .arg(Arg::with_name("open-dir")
+             .long("open-dir")
+             .value_name("FD:DIR")
+             .help("Open <DIR> to pass as fd <FD>")
+             .multiple(true)
+             .number_of_values(1))
+        .arg(Arg::with_name("args")
+             .help("Command line to execute with pre-opened FD inherited")
+             .last(true)
+             .required(true)
+             .multiple(true))
+        .get_matches();
+
+    let ro_files = parse_and_create_file_mapping(matches.values_of("open-ro"), |path| {
+        OpenOptions::new().read(true).open(path).with_context(|| format!("Open {} read-only", path))
+    })?;
+
+    let rw_files = parse_and_create_file_mapping(matches.values_of("open-rw"), |path| {
+        OpenOptions::new()
+            .read(true)
+            .write(true)
+            .create(true)
+            .open(path)
+            .with_context(|| format!("Open {} read-write", path))
+    })?;
+
+    let dir_files = parse_and_create_file_mapping(matches.values_of("open-dir"), |path| {
+        Dir::open(path, OFlag::O_DIRECTORY | OFlag::O_RDWR, Mode::S_IRWXU)
+            .with_context(|| format!("Open {} directory", path))
+    })?;
+
+    let cmdline_args: Vec<_> = matches.values_of("args").unwrap().map(|s| s.to_string()).collect();
+
+    Ok(Args { ro_files, rw_files, dir_files, cmdline_args })
+}
+
+fn try_main() -> Result<()> {
+    let args = parse_args()?;
+
+    let mut command = Command::new(&args.cmdline_args[0]);
+    command.args(&args.cmdline_args[1..]);
+
+    // Set up FD mappings in the child process.
+    let mut fd_mappings = Vec::new();
+    fd_mappings.extend(args.ro_files.iter().map(FileMapping::as_fd_mapping));
+    fd_mappings.extend(args.rw_files.iter().map(FileMapping::as_fd_mapping));
+    fd_mappings.extend(args.dir_files.iter().map(FileMapping::as_fd_mapping));
+    command.fd_mappings(fd_mappings)?;
+
+    debug!("Spawning {:?}", command);
+    command.spawn()?;
+    Ok(())
+}
+
+fn main() {
+    android_logger::init_once(
+        android_logger::Config::default()
+            .with_tag("open_then_run")
+            .with_min_level(log::Level::Debug),
+    );
+
+    if let Err(e) = try_main() {
+        error!("Failed with {:?}", e);
+        std::process::exit(1);
+    }
+}