Adding upstream version 110.0.1.upstream/110.0.1upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

20 files changed, 5105 insertions, 0 deletions

diff --git a/testing/mozbase/rust/mozdevice/Cargo.toml b/testing/mozbase/rust/mozdevice/Cargo.toml
new file mode 100644
index 0000000000..df3eeb018c
--- /dev/null
+++ b/testing/mozbase/rust/mozdevice/Cargo.toml
@@ -0,0 +1,26 @@
+[package]
+edition = "2018"
+name = "mozdevice"
+version = "0.5.0"
+authors = ["Mozilla"]
+description = "Client library for the Android Debug Bridge (adb)"
+keywords = [
+    "adb",
+    "android",
+    "firefox",
+    "geckoview",
+    "mozilla",
+]
+license = "MPL-2.0"
+repository = "https://hg.mozilla.org/mozilla-central/file/tip/testing/mozbase/rust/mozdevice"
+
+[dependencies]
+log = { version = "0.4", features = ["std"] }
+once_cell = "1.4.0"
+regex = { version = "1", default-features = false, features = ["perf", "std"] }
+tempfile = "3"
+thiserror = "1.0.25"
+walkdir = "2"
+unix_path = "1.0"
+uuid = { version = "1.0", features = ["serde", "v4"] }
+
diff --git a/testing/mozbase/rust/mozdevice/src/adb.rs b/testing/mozbase/rust/mozdevice/src/adb.rs
new file mode 100644
index 0000000000..9d9c91fd07
--- /dev/null
+++ b/testing/mozbase/rust/mozdevice/src/adb.rs
@@ -0,0 +1,38 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#[derive(Debug, PartialEq)]
+pub enum SyncCommand {
+    Data,
+    Dent,
+    Done,
+    Fail,
+    List,
+    Okay,
+    Quit,
+    Recv,
+    Send,
+    Stat,
+}
+
+impl SyncCommand {
+    // Returns the byte serialisation of the protocol status.
+    pub fn code(&self) -> &'static [u8; 4] {
+        use self::SyncCommand::*;
+        match *self {
+            Data => b"DATA",
+            Dent => b"DENT",
+            Done => b"DONE",
+            Fail => b"FAIL",
+            List => b"LIST",
+            Okay => b"OKAY",
+            Quit => b"QUIT",
+            Recv => b"RECV",
+            Send => b"SEND",
+            Stat => b"STAT",
+        }
+    }
+}
+
+pub type DeviceSerial = String;
diff --git a/testing/mozbase/rust/mozdevice/src/lib.rs b/testing/mozbase/rust/mozdevice/src/lib.rs
new file mode 100644
index 0000000000..631c4acf2a
--- /dev/null
+++ b/testing/mozbase/rust/mozdevice/src/lib.rs
@@ -0,0 +1,1068 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+pub mod adb;
+pub mod shell;
+
+#[cfg(test)]
+pub mod test;
+
+use log::{debug, info, trace, warn};
+use once_cell::sync::Lazy;
+use regex::Regex;
+use std::collections::BTreeMap;
+use std::convert::TryFrom;
+use std::fs::File;
+use std::io::{self, Read, Write};
+use std::iter::FromIterator;
+use std::net::TcpStream;
+use std::num::{ParseIntError, TryFromIntError};
+use std::path::{Component, Path};
+use std::str::{FromStr, Utf8Error};
+use std::time::{Duration, SystemTime};
+use thiserror::Error;
+pub use unix_path::{Path as UnixPath, PathBuf as UnixPathBuf};
+use uuid::Uuid;
+use walkdir::WalkDir;
+
+use crate::adb::{DeviceSerial, SyncCommand};
+
+pub type Result<T> = std::result::Result<T, DeviceError>;
+
+static SYNC_REGEX: Lazy<Regex> = Lazy::new(|| Regex::new(r"[^A-Za-z0-9_@%+=:,./-]").unwrap());
+
+#[derive(Debug, Clone, Copy, PartialEq)]
+pub enum AndroidStorageInput {
+    Auto,
+    App,
+    Internal,
+    Sdcard,
+}
+
+impl FromStr for AndroidStorageInput {
+    type Err = DeviceError;
+
+    fn from_str(s: &str) -> Result<Self> {
+        match s {
+            "auto" => Ok(AndroidStorageInput::Auto),
+            "app" => Ok(AndroidStorageInput::App),
+            "internal" => Ok(AndroidStorageInput::Internal),
+            "sdcard" => Ok(AndroidStorageInput::Sdcard),
+            _ => Err(DeviceError::InvalidStorage),
+        }
+    }
+}
+
+impl Default for AndroidStorageInput {
+    fn default() -> Self {
+        AndroidStorageInput::Auto
+    }
+}
+
+#[derive(Debug, Clone, Copy, PartialEq)]
+pub enum AndroidStorage {
+    App,
+    Internal,
+    Sdcard,
+}
+
+#[derive(Debug, Error)]
+pub enum DeviceError {
+    #[error("{0}")]
+    Adb(String),
+    #[error(transparent)]
+    FromInt(#[from] TryFromIntError),
+    #[error("Invalid storage")]
+    InvalidStorage,
+    #[error(transparent)]
+    Io(#[from] io::Error),
+    #[error("Missing package")]
+    MissingPackage,
+    #[error("Multiple Android devices online")]
+    MultipleDevices,
+    #[error(transparent)]
+    ParseInt(#[from] ParseIntError),
+    #[error("Unknown Android device with serial '{0}'")]
+    UnknownDevice(String),
+    #[error(transparent)]
+    Utf8(#[from] Utf8Error),
+    #[error(transparent)]
+    WalkDir(#[from] walkdir::Error),
+}
+
+fn encode_message(payload: &str) -> Result<String> {
+    let hex_length = u16::try_from(payload.len()).map(|len| format!("{:0>4X}", len))?;
+
+    Ok(format!("{}{}", hex_length, payload))
+}
+
+fn parse_device_info(line: &str) -> Option<DeviceInfo> {
+    // Turn "serial\tdevice key1:value1 key2:value2 ..." into a `DeviceInfo`.
+    let mut pairs = line.split_whitespace();
+    let serial = pairs.next();
+    let state = pairs.next();
+    if let (Some(serial), Some("device")) = (serial, state) {
+        let info: BTreeMap<String, String> = pairs
+            .filter_map(|pair| {
+                let mut kv = pair.split(':');
+                if let (Some(k), Some(v), None) = (kv.next(), kv.next(), kv.next()) {
+                    Some((k.to_owned(), v.to_owned()))
+                } else {
+                    None
+                }
+            })
+            .collect();
+
+        Some(DeviceInfo {
+            serial: serial.to_owned(),
+            info,
+        })
+    } else {
+        None
+    }
+}
+
+/// Reads the payload length of a host message from the stream.
+fn read_length<R: Read>(stream: &mut R) -> Result<usize> {
+    let mut bytes: [u8; 4] = [0; 4];
+    stream.read_exact(&mut bytes)?;
+
+    let response = std::str::from_utf8(&bytes)?;
+
+    Ok(usize::from_str_radix(response, 16)?)
+}
+
+/// Reads the payload length of a device message from the stream.
+fn read_length_little_endian(reader: &mut dyn Read) -> Result<usize> {
+    let mut bytes: [u8; 4] = [0; 4];
+    reader.read_exact(&mut bytes)?;
+
+    let n: usize = (bytes[0] as usize)
+        + ((bytes[1] as usize) << 8)
+        + ((bytes[2] as usize) << 16)
+        + ((bytes[3] as usize) << 24);
+
+    Ok(n)
+}
+
+/// Writes the payload length of a device message to the stream.
+fn write_length_little_endian(writer: &mut dyn Write, n: usize) -> Result<usize> {
+    let mut bytes = [0; 4];
+    bytes[0] = (n & 0xFF) as u8;
+    bytes[1] = ((n >> 8) & 0xFF) as u8;
+    bytes[2] = ((n >> 16) & 0xFF) as u8;
+    bytes[3] = ((n >> 24) & 0xFF) as u8;
+
+    writer.write(&bytes[..]).map_err(DeviceError::Io)
+}
+
+fn read_response(stream: &mut TcpStream, has_output: bool, has_length: bool) -> Result<Vec<u8>> {
+    let mut bytes: [u8; 1024] = [0; 1024];
+
+    stream.read_exact(&mut bytes[0..4])?;
+
+    if !bytes.starts_with(SyncCommand::Okay.code()) {
+        let n = bytes.len().min(read_length(stream)?);
+        stream.read_exact(&mut bytes[0..n])?;
+
+        let message = std::str::from_utf8(&bytes[0..n]).map(|s| format!("adb error: {}", s))?;
+
+        return Err(DeviceError::Adb(message));
+    }
+
+    let mut response = Vec::new();
+
+    if has_output {
+        stream.read_to_end(&mut response)?;
+
+        if response.starts_with(SyncCommand::Okay.code()) {
+            // Sometimes the server produces OKAYOKAY.  Sometimes there is a transport OKAY and
+            // then the underlying command OKAY.  This is straight from `chromedriver`.
+            response = response.split_off(4);
+        }
+
+        if response.starts_with(SyncCommand::Fail.code()) {
+            // The server may even produce OKAYFAIL, which means the underlying
+            // command failed. First split-off the `FAIL` and length of the message.
+            response = response.split_off(8);
+
+            let message = std::str::from_utf8(&response).map(|s| format!("adb error: {}", s))?;
+
+            return Err(DeviceError::Adb(message));
+        }
+
+        if has_length {
+            if response.len() >= 4 {
+                let message = response.split_off(4);
+                let slice: &mut &[u8] = &mut &*response;
+
+                let n = read_length(slice)?;
+                if n != message.len() {
+                    warn!("adb server response contained hexstring len {} but remaining message length is {}", n, message.len());
+                }
+
+                trace!(
+                    "adb server response was {:?}",
+                    std::str::from_utf8(&message)?
+                );
+
+                return Ok(message);
+            } else {
+                return Err(DeviceError::Adb(format!(
+                    "adb server response did not contain expected hexstring length: {:?}",
+                    std::str::from_utf8(&response)?
+                )));
+            }
+        }
+    }
+
+    Ok(response)
+}
+
+/// Detailed information about an ADB device.
+#[derive(Debug, Eq, PartialEq, Ord, PartialOrd)]
+pub struct DeviceInfo {
+    pub serial: DeviceSerial,
+    pub info: BTreeMap<String, String>,
+}
+
+/// Represents a connection to an ADB host, which multiplexes the connections to
+/// individual devices.
+#[derive(Debug)]
+pub struct Host {
+    /// The TCP host to connect to.  Defaults to `"localhost"`.
+    pub host: Option<String>,
+    /// The TCP port to connect to.  Defaults to `5037`.
+    pub port: Option<u16>,
+    /// Optional TCP read timeout duration.  Defaults to 2s.
+    pub read_timeout: Option<Duration>,
+    /// Optional TCP write timeout duration.  Defaults to 2s.
+    pub write_timeout: Option<Duration>,
+}
+
+impl Default for Host {
+    fn default() -> Host {
+        Host {
+            host: Some("localhost".to_string()),
+            port: Some(5037),
+            read_timeout: Some(Duration::from_secs(2)),
+            write_timeout: Some(Duration::from_secs(2)),
+        }
+    }
+}
+
+impl Host {
+    /// Searches for available devices, and selects the one as specified by `device_serial`.
+    ///
+    /// If multiple devices are online, and no device has been specified,
+    /// the `ANDROID_SERIAL` environment variable can be used to select one.
+    pub fn device_or_default<T: AsRef<str>>(
+        self,
+        device_serial: Option<&T>,
+        storage: AndroidStorageInput,
+    ) -> Result<Device> {
+        let serials: Vec<String> = self
+            .devices::<Vec<_>>()?
+            .into_iter()
+            .map(|d| d.serial)
+            .collect();
+
+        if let Some(ref serial) = device_serial
+            .map(|v| v.as_ref().to_owned())
+            .or_else(|| std::env::var("ANDROID_SERIAL").ok())
+        {
+            if !serials.contains(serial) {
+                return Err(DeviceError::UnknownDevice(serial.clone()));
+            }
+
+            return Device::new(self, serial.to_owned(), storage);
+        }
+
+        if serials.len() > 1 {
+            return Err(DeviceError::MultipleDevices);
+        }
+
+        if let Some(ref serial) = serials.first() {
+            return Device::new(self, serial.to_owned().to_string(), storage);
+        }
+
+        Err(DeviceError::Adb("No Android devices are online".to_owned()))
+    }
+
+    pub fn connect(&self) -> Result<TcpStream> {
+        let stream = TcpStream::connect(format!(
+            "{}:{}",
+            self.host.clone().unwrap_or_else(|| "localhost".to_owned()),
+            self.port.unwrap_or(5037)
+        ))?;
+        stream.set_read_timeout(self.read_timeout)?;
+        stream.set_write_timeout(self.write_timeout)?;
+        Ok(stream)
+    }
+
+    pub fn execute_command(
+        &self,
+        command: &str,
+        has_output: bool,
+        has_length: bool,
+    ) -> Result<String> {
+        let mut stream = self.connect()?;
+
+        stream.write_all(encode_message(command)?.as_bytes())?;
+        let bytes = read_response(&mut stream, has_output, has_length)?;
+        // TODO: should we assert no bytes were read?
+
+        let response = std::str::from_utf8(&bytes)?;
+
+        Ok(response.to_owned())
+    }
+
+    pub fn execute_host_command(
+        &self,
+        host_command: &str,
+        has_length: bool,
+        has_output: bool,
+    ) -> Result<String> {
+        self.execute_command(&format!("host:{}", host_command), has_output, has_length)
+    }
+
+    pub fn features<B: FromIterator<String>>(&self) -> Result<B> {
+        let features = self.execute_host_command("features", true, true)?;
+        Ok(features.split(',').map(|x| x.to_owned()).collect())
+    }
+
+    pub fn devices<B: FromIterator<DeviceInfo>>(&self) -> Result<B> {
+        let response = self.execute_host_command("devices-l", true, true)?;
+
+        let infos: B = response.lines().filter_map(parse_device_info).collect();
+
+        Ok(infos)
+    }
+}
+
+/// Represents an ADB device.
+#[derive(Debug)]
+pub struct Device {
+    /// ADB host that controls this device.
+    pub host: Host,
+
+    /// Serial number uniquely identifying this ADB device.
+    pub serial: DeviceSerial,
+
+    /// adb running as root
+    pub adbd_root: bool,
+
+    /// Flag for rooted device
+    pub is_rooted: bool,
+
+    /// "su 0" command available
+    pub su_0_root: bool,
+
+    /// "su -c" command available
+    pub su_c_root: bool,
+
+    pub run_as_package: Option<String>,
+
+    pub storage: AndroidStorage,
+
+    /// Cache intermediate tempfile name used in pushing via run_as.
+    pub tempfile: UnixPathBuf,
+}
+
+#[derive(Debug, Eq, PartialEq, Ord, PartialOrd)]
+pub struct RemoteDirEntry {
+    depth: usize,
+    metadata: RemoteMetadata,
+    name: String,
+}
+
+#[derive(Debug, Eq, PartialEq, Ord, PartialOrd)]
+pub enum RemoteMetadata {
+    RemoteFile(RemoteFileMetadata),
+    RemoteDir,
+    RemoteSymlink,
+}
+#[derive(Debug, Eq, PartialEq, Ord, PartialOrd)]
+pub struct RemoteFileMetadata {
+    mode: usize,
+    size: usize,
+}
+
+impl Device {
+    pub fn new(host: Host, serial: DeviceSerial, storage: AndroidStorageInput) -> Result<Device> {
+        let mut device = Device {
+            host,
+            serial,
+            adbd_root: false,
+            is_rooted: false,
+            run_as_package: None,
+            storage: AndroidStorage::App,
+            su_c_root: false,
+            su_0_root: false,
+            tempfile: UnixPathBuf::from("/data/local/tmp"),
+        };
+        device
+            .tempfile
+            .push(Uuid::new_v4().as_hyphenated().to_string());
+
+        // check for rooted devices
+        let uid_check = |id: String| id.contains("uid=0");
+        device.adbd_root = device
+            .execute_host_shell_command("id")
+            .map_or(false, uid_check);
+        device.su_0_root = device
+            .execute_host_shell_command("su 0 id")
+            .map_or(false, uid_check);
+        device.su_c_root = device
+            .execute_host_shell_command("su -c id")
+            .map_or(false, uid_check);
+        device.is_rooted = device.adbd_root || device.su_0_root || device.su_c_root;
+
+        device.storage = match storage {
+            AndroidStorageInput::App => AndroidStorage::App,
+            AndroidStorageInput::Internal => AndroidStorage::Internal,
+            AndroidStorageInput::Sdcard => AndroidStorage::Sdcard,
+            AndroidStorageInput::Auto => AndroidStorage::Sdcard,
+        };
+
+        if device.is_rooted {
+            info!("Device is rooted");
+
+            // Set Permissive=1 if we have root.
+            device.execute_host_shell_command("setenforce permissive")?;
+        } else {
+            info!("Device is unrooted");
+        }
+
+        Ok(device)
+    }
+
+    pub fn clear_app_data(&self, package: &str) -> Result<bool> {
+        self.execute_host_shell_command(&format!("pm clear {}", package))
+            .map(|v| v.contains("Success"))
+    }
+
+    pub fn create_dir(&self, path: &UnixPath) -> Result<()> {
+        debug!("Creating {}", path.display());
+
+        let enable_run_as = self.enable_run_as_for_path(path);
+        self.execute_host_shell_command_as(&format!("mkdir -p {}", path.display()), enable_run_as)?;
+
+        Ok(())
+    }
+
+    pub fn chmod(&self, path: &UnixPath, mask: &str, recursive: bool) -> Result<()> {
+        let enable_run_as = self.enable_run_as_for_path(path);
+
+        let recursive = match recursive {
+            true => " -R",
+            false => "",
+        };
+
+        self.execute_host_shell_command_as(
+            &format!("chmod {} {} {}", recursive, mask, path.display()),
+            enable_run_as,
+        )?;
+
+        Ok(())
+    }
+
+    pub fn execute_host_command(
+        &self,
+        command: &str,
+        has_output: bool,
+        has_length: bool,
+    ) -> Result<String> {
+        let mut stream = self.host.connect()?;
+
+        let switch_command = format!("host:transport:{}", self.serial);
+        trace!("execute_host_command: >> {:?}", &switch_command);
+        stream.write_all(encode_message(&switch_command)?.as_bytes())?;
+        let _bytes = read_response(&mut stream, false, false)?;
+        trace!("execute_host_command: << {:?}", _bytes);
+        // TODO: should we assert no bytes were read?
+
+        trace!("execute_host_command: >> {:?}", &command);
+        stream.write_all(encode_message(command)?.as_bytes())?;
+        let bytes = read_response(&mut stream, has_output, has_length)?;
+        let response = std::str::from_utf8(&bytes)?;
+        trace!("execute_host_command: << {:?}", response);
+
+        // Unify new lines by removing possible carriage returns
+        Ok(response.replace("\r\n", "\n"))
+    }
+
+    pub fn enable_run_as_for_path(&self, path: &UnixPath) -> bool {
+        match &self.run_as_package {
+            Some(package) => {
+                let mut p = UnixPathBuf::from("/data/data/");
+                p.push(package);
+                path.starts_with(p)
+            }
+            None => false,
+        }
+    }
+
+    pub fn execute_host_shell_command(&self, shell_command: &str) -> Result<String> {
+        self.execute_host_shell_command_as(shell_command, false)
+    }
+
+    pub fn execute_host_shell_command_as(
+        &self,
+        shell_command: &str,
+        enable_run_as: bool,
+    ) -> Result<String> {
+        // We don't want to duplicate su invocations.
+        if shell_command.starts_with("su") {
+            return self.execute_host_command(&format!("shell:{}", shell_command), true, false);
+        }
+
+        let has_outer_quotes = shell_command.starts_with('"') && shell_command.ends_with('"')
+            || shell_command.starts_with('\'') && shell_command.ends_with('\'');
+
+        if self.adbd_root {
+            return self.execute_host_command(&format!("shell:{}", shell_command), true, false);
+        }
+
+        if self.su_0_root {
+            return self.execute_host_command(
+                &format!("shell:su 0 {}", shell_command),
+                true,
+                false,
+            );
+        }
+
+        if self.su_c_root {
+            if has_outer_quotes {
+                return self.execute_host_command(
+                    &format!("shell:su -c {}", shell_command),
+                    true,
+                    false,
+                );
+            }
+
+            if SYNC_REGEX.is_match(shell_command) {
+                let arg: &str = &shell_command.replace('\'', "'\"'\"'")[..];
+                return self.execute_host_command(&format!("shell:su -c '{}'", arg), true, false);
+            }
+
+            return self.execute_host_command(
+                &format!("shell:su -c \"{}\"", shell_command),
+                true,
+                false,
+            );
+        }
+
+        // Execute command as package
+        if enable_run_as {
+            let run_as_package = self
+                .run_as_package
+                .as_ref()
+                .ok_or(DeviceError::MissingPackage)?;
+
+            if has_outer_quotes {
+                return self.execute_host_command(
+                    &format!("shell:run-as {} {}", run_as_package, shell_command),
+                    true,
+                    false,
+                );
+            }
+
+            if SYNC_REGEX.is_match(shell_command) {
+                let arg: &str = &shell_command.replace('\'', "'\"'\"'")[..];
+                return self.execute_host_command(
+                    &format!("shell:run-as {} {}", run_as_package, arg),
+                    true,
+                    false,
+                );
+            }
+
+            return self.execute_host_command(
+                &format!("shell:run-as {} \"{}\"", run_as_package, shell_command),
+                true,
+                false,
+            );
+        }
+
+        self.execute_host_command(&format!("shell:{}", shell_command), true, false)
+    }
+
+    pub fn is_app_installed(&self, package: &str) -> Result<bool> {
+        self.execute_host_shell_command(&format!("pm path {}", package))
+            .map(|v| v.contains("package:"))
+    }
+
+    pub fn launch<T: AsRef<str>>(
+        &self,
+        package: &str,
+        activity: &str,
+        am_start_args: &[T],
+    ) -> Result<bool> {
+        let mut am_start = format!("am start -W -n {}/{}", package, activity);
+
+        for arg in am_start_args {
+            am_start.push(' ');
+            if SYNC_REGEX.is_match(arg.as_ref()) {
+                am_start.push_str(&format!("\"{}\"", &shell::escape(arg.as_ref())));
+            } else {
+                am_start.push_str(&shell::escape(arg.as_ref()));
+            };
+        }
+
+        self.execute_host_shell_command(&am_start)
+            .map(|v| v.contains("Complete"))
+    }
+
+    pub fn force_stop(&self, package: &str) -> Result<()> {
+        debug!("Force stopping Android package: {}", package);
+        self.execute_host_shell_command(&format!("am force-stop {}", package))
+            .and(Ok(()))
+    }
+
+    pub fn forward_port(&self, local: u16, remote: u16) -> Result<u16> {
+        let command = format!(
+            "host-serial:{}:forward:tcp:{};tcp:{}",
+            self.serial, local, remote
+        );
+        let response = self.host.execute_command(&command, true, false)?;
+
+        if local == 0 {
+            Ok(response.parse::<u16>()?)
+        } else {
+            Ok(local)
+        }
+    }
+
+    pub fn kill_forward_port(&self, local: u16) -> Result<()> {
+        let command = format!("host-serial:{}:killforward:tcp:{}", self.serial, local);
+        self.execute_host_command(&command, true, false).and(Ok(()))
+    }
+
+    pub fn kill_forward_all_ports(&self) -> Result<()> {
+        let command = format!("host-serial:{}:killforward-all", self.serial);
+        self.execute_host_command(&command, false, false)
+            .and(Ok(()))
+    }
+
+    pub fn reverse_port(&self, remote: u16, local: u16) -> Result<u16> {
+        let command = format!("reverse:forward:tcp:{};tcp:{}", remote, local);
+        let response = self.execute_host_command(&command, true, false)?;
+
+        if remote == 0 {
+            Ok(response.parse::<u16>()?)
+        } else {
+            Ok(remote)
+        }
+    }
+
+    pub fn kill_reverse_port(&self, remote: u16) -> Result<()> {
+        let command = format!("reverse:killforward:tcp:{}", remote);
+        self.execute_host_command(&command, true, true).and(Ok(()))
+    }
+
+    pub fn kill_reverse_all_ports(&self) -> Result<()> {
+        let command = "reverse:killforward-all".to_owned();
+        self.execute_host_command(&command, false, false)
+            .and(Ok(()))
+    }
+
+    pub fn list_dir(&self, src: &UnixPath) -> Result<Vec<RemoteDirEntry>> {
+        let src = src.to_path_buf();
+        let mut queue = vec![(src.clone(), 0, "".to_string())];
+
+        let mut listings = Vec::new();
+
+        while let Some((next, depth, prefix)) = queue.pop() {
+            for listing in self.list_dir_flat(&next, depth, prefix)? {
+                if listing.metadata == RemoteMetadata::RemoteDir {
+                    let mut child = src.clone();
+                    child.push(listing.name.clone());
+                    queue.push((child, depth + 1, listing.name.clone()));
+                }
+
+                listings.push(listing);
+            }
+        }
+
+        Ok(listings)
+    }
+
+    fn list_dir_flat(
+        &self,
+        src: &UnixPath,
+        depth: usize,
+        prefix: String,
+    ) -> Result<Vec<RemoteDirEntry>> {
+        // Implement the ADB protocol to list a directory from the device.
+        let mut stream = self.host.connect()?;
+
+        // Send "host:transport" command with device serial
+        let message = encode_message(&format!("host:transport:{}", self.serial))?;
+        stream.write_all(message.as_bytes())?;
+        let _bytes = read_response(&mut stream, false, true)?;
+
+        // Send "sync:" command to initialize file transfer
+        let message = encode_message("sync:")?;
+        stream.write_all(message.as_bytes())?;
+        let _bytes = read_response(&mut stream, false, true)?;
+
+        // Send "LIST" command with name of the directory
+        stream.write_all(SyncCommand::List.code())?;
+        let args_ = format!("{}", src.display());
+        let args = args_.as_bytes();
+        write_length_little_endian(&mut stream, args.len())?;
+        stream.write_all(args)?;
+
+        // Use the maximum 64KB buffer to transfer the file contents.
+        let mut buf = [0; 64 * 1024];
+
+        let mut listings = Vec::new();
+
+        // Read "DENT" command one or more times for the directory entries
+        loop {
+            stream.read_exact(&mut buf[0..4])?;
+
+            if &buf[0..4] == SyncCommand::Dent.code() {
+                // From https://github.com/cstyan/adbDocumentation/blob/6d025b3e4af41be6f93d37f516a8ac7913688623/README.md:
+                //
+                // A four-byte integer representing file mode - first 9 bits of this mode represent
+                // the file permissions, as with chmod mode. Bits 14 to 16 seem to represent the
+                // file type, one of 0b100 (file), 0b010 (directory), 0b101 (symlink)
+                // A four-byte integer representing file size.
+                // A four-byte integer representing last modified time in seconds since Unix Epoch.
+                // A four-byte integer representing file name length.
+                // A utf-8 string representing the file name.
+                let mode = read_length_little_endian(&mut stream)?;
+                let size = read_length_little_endian(&mut stream)?;
+                let _time = read_length_little_endian(&mut stream)?;
+                let name_length = read_length_little_endian(&mut stream)?;
+                stream.read_exact(&mut buf[0..name_length])?;
+
+                let mut name = std::str::from_utf8(&buf[0..name_length])?.to_owned();
+
+                if name == "." || name == ".." {
+                    continue;
+                }
+
+                if !prefix.is_empty() {
+                    name = format!("{}/{}", prefix, &name);
+                }
+
+                let file_type = (mode >> 13) & 0b111;
+                let metadata = match file_type {
+                    0b010 => RemoteMetadata::RemoteDir,
+                    0b100 => RemoteMetadata::RemoteFile(RemoteFileMetadata {
+                        mode: mode & 0b111111111,
+                        size,
+                    }),
+                    0b101 => RemoteMetadata::RemoteSymlink,
+                    _ => return Err(DeviceError::Adb(format!("Invalid file mode {}", file_type))),
+                };
+
+                listings.push(RemoteDirEntry {
+                    name,
+                    depth,
+                    metadata,
+                });
+            } else if &buf[0..4] == SyncCommand::Done.code() {
+                // "DONE" command indicates end of file transfer
+                break;
+            } else if &buf[0..4] == SyncCommand::Fail.code() {
+                let n = buf.len().min(read_length_little_endian(&mut stream)?);
+
+                stream.read_exact(&mut buf[0..n])?;
+
+                let message = std::str::from_utf8(&buf[0..n])
+                    .map(|s| format!("adb error: {}", s))
+                    .unwrap_or_else(|_| "adb error was not utf-8".into());
+
+                return Err(DeviceError::Adb(message));
+            } else {
+                return Err(DeviceError::Adb("FAIL (unknown)".to_owned()));
+            }
+        }
+
+        Ok(listings)
+    }
+
+    pub fn path_exists(&self, path: &UnixPath, enable_run_as: bool) -> Result<bool> {
+        self.execute_host_shell_command_as(format!("ls {}", path.display()).as_str(), enable_run_as)
+            .map(|path| !path.contains("No such file or directory"))
+    }
+
+    pub fn pull(&self, src: &UnixPath, buffer: &mut dyn Write) -> Result<()> {
+        // Implement the ADB protocol to receive a file from the device.
+        let mut stream = self.host.connect()?;
+
+        // Send "host:transport" command with device serial
+        let message = encode_message(&format!("host:transport:{}", self.serial))?;
+        stream.write_all(message.as_bytes())?;
+        let _bytes = read_response(&mut stream, false, true)?;
+
+        // Send "sync:" command to initialize file transfer
+        let message = encode_message("sync:")?;
+        stream.write_all(message.as_bytes())?;
+        let _bytes = read_response(&mut stream, false, true)?;
+
+        // Send "RECV" command with name of the file
+        stream.write_all(SyncCommand::Recv.code())?;
+        let args_string = format!("{}", src.display());
+        let args = args_string.as_bytes();
+        write_length_little_endian(&mut stream, args.len())?;
+        stream.write_all(args)?;
+
+        // Use the maximum 64KB buffer to transfer the file contents.
+        let mut buf = [0; 64 * 1024];
+
+        // Read "DATA" command one or more times for the file content
+        loop {
+            stream.read_exact(&mut buf[0..4])?;
+
+            if &buf[0..4] == SyncCommand::Data.code() {
+                let len = read_length_little_endian(&mut stream)?;
+                stream.read_exact(&mut buf[0..len])?;
+                buffer.write_all(&buf[0..len])?;
+            } else if &buf[0..4] == SyncCommand::Done.code() {
+                // "DONE" command indicates end of file transfer
+                break;
+            } else if &buf[0..4] == SyncCommand::Fail.code() {
+                let n = buf.len().min(read_length_little_endian(&mut stream)?);
+
+                stream.read_exact(&mut buf[0..n])?;
+
+                let message = std::str::from_utf8(&buf[0..n])
+                    .map(|s| format!("adb error: {}", s))
+                    .unwrap_or_else(|_| "adb error was not utf-8".into());
+
+                return Err(DeviceError::Adb(message));
+            } else {
+                return Err(DeviceError::Adb("FAIL (unknown)".to_owned()));
+            }
+        }
+
+        Ok(())
+    }
+
+    pub fn pull_dir(&self, src: &UnixPath, dest_dir: &Path) -> Result<()> {
+        let src = src.to_path_buf();
+        let dest_dir = dest_dir.to_path_buf();
+
+        for entry in self.list_dir(&src)? {
+            match entry.metadata {
+                RemoteMetadata::RemoteSymlink => {} // Ignored.
+                RemoteMetadata::RemoteDir => {
+                    let mut d = dest_dir.clone();
+                    d.push(&entry.name);
+
+                    std::fs::create_dir_all(&d)?;
+                }
+                RemoteMetadata::RemoteFile(_) => {
+                    let mut s = src.clone();
+                    s.push(&entry.name);
+                    let mut d = dest_dir.clone();
+                    d.push(&entry.name);
+
+                    self.pull(&s, &mut File::create(d)?)?;
+                }
+            }
+        }
+
+        Ok(())
+    }
+
+    pub fn push(&self, buffer: &mut dyn Read, dest: &UnixPath, mode: u32) -> Result<()> {
+        // Implement the ADB protocol to send a file to the device.
+        // The protocol consists of the following steps:
+        // * Send "host:transport" command with device serial
+        // * Send "sync:" command to initialize file transfer
+        // * Send "SEND" command with name and mode of the file
+        // * Send "DATA" command one or more times for the file content
+        // * Send "DONE" command to indicate end of file transfer
+
+        let enable_run_as = self.enable_run_as_for_path(&dest.to_path_buf());
+        let dest1 = match enable_run_as {
+            true => self.tempfile.as_path(),
+            false => UnixPath::new(dest),
+        };
+
+        // If the destination directory does not exist, adb will
+        // create it and any necessary ancestors however it will not
+        // set the directory permissions to 0o777.  In addition,
+        // Android 9 (P) has a bug in its push implementation which
+        // will cause a push which creates directories to fail with
+        // the error `secure_mkdirs failed: Operation not
+        // permitted`. We can work around this by creating the
+        // destination directories prior to the push.  Collect the
+        // ancestors of the destination directory which do not yet
+        // exist so we can create them and adjust their permissions
+        // prior to performing the push.
+        let mut current = dest.parent();
+        let mut leaf: Option<&UnixPath> = None;
+        let mut root: Option<&UnixPath> = None;
+
+        while let Some(path) = current {
+            if self.path_exists(path, enable_run_as)? {
+                break;
+            }
+            if leaf.is_none() {
+                leaf = Some(path);
+            }
+            root = Some(path);
+            current = path.parent();
+        }
+
+        if let Some(path) = leaf {
+            self.create_dir(path)?;
+        }
+
+        if let Some(path) = root {
+            self.chmod(path, "777", true)?;
+        }
+
+        let mut stream = self.host.connect()?;
+
+        let message = encode_message(&format!("host:transport:{}", self.serial))?;
+        stream.write_all(message.as_bytes())?;
+        let _bytes = read_response(&mut stream, false, true)?;
+
+        let message = encode_message("sync:")?;
+        stream.write_all(message.as_bytes())?;
+        let _bytes = read_response(&mut stream, false, true)?;
+
+        stream.write_all(SyncCommand::Send.code())?;
+        let args_ = format!("{},{}", dest1.display(), mode);
+        let args = args_.as_bytes();
+        write_length_little_endian(&mut stream, args.len())?;
+        stream.write_all(args)?;
+
+        // Use a 32KB buffer to transfer the file contents
+        // TODO: Maybe adjust to maxdata (256KB)
+        let mut buf = [0; 32 * 1024];
+
+        loop {
+            let len = buffer.read(&mut buf)?;
+
+            if len == 0 {
+                break;
+            }
+
+            stream.write_all(SyncCommand::Data.code())?;
+            write_length_little_endian(&mut stream, len)?;
+            stream.write_all(&buf[0..len])?;
+        }
+
+        // https://android.googlesource.com/platform/system/core/+/master/adb/SYNC.TXT#66
+        //
+        // When the file is transferred a sync request "DONE" is sent, where length is set
+        // to the last modified time for the file. The server responds to this last
+        // request (but not to chunk requests) with an "OKAY" sync response (length can
+        // be ignored).
+        let time: u32 = ((SystemTime::now().duration_since(SystemTime::UNIX_EPOCH))
+            .unwrap()
+            .as_secs()
+            & 0xFFFF_FFFF) as u32;
+
+        stream.write_all(SyncCommand::Done.code())?;
+        write_length_little_endian(&mut stream, time as usize)?;
+
+        // Status.
+        stream.read_exact(&mut buf[0..4])?;
+
+        if buf.starts_with(SyncCommand::Okay.code()) {
+            if enable_run_as {
+                // Use cp -a to preserve the permissions set by push.
+                let result = self.execute_host_shell_command_as(
+                    format!("cp -aR {} {}", dest1.display(), dest.display()).as_str(),
+                    enable_run_as,
+                );
+                if self.remove(dest1).is_err() {
+                    warn!("Failed to remove {}", dest1.display());
+                }
+                result?;
+            }
+            Ok(())
+        } else if buf.starts_with(SyncCommand::Fail.code()) {
+            if enable_run_as && self.remove(dest1).is_err() {
+                warn!("Failed to remove {}", dest1.display());
+            }
+            let n = buf.len().min(read_length_little_endian(&mut stream)?);
+
+            stream.read_exact(&mut buf[0..n])?;
+
+            let message = std::str::from_utf8(&buf[0..n])
+                .map(|s| format!("adb error: {}", s))
+                .unwrap_or_else(|_| "adb error was not utf-8".into());
+
+            Err(DeviceError::Adb(message))
+        } else {
+            if self.remove(dest1).is_err() {
+                warn!("Failed to remove {}", dest1.display());
+            }
+            Err(DeviceError::Adb("FAIL (unknown)".to_owned()))
+        }
+    }
+
+    pub fn push_dir(&self, source: &Path, dest_dir: &UnixPath, mode: u32) -> Result<()> {
+        debug!("Pushing {} to {}", source.display(), dest_dir.display());
+
+        let walker = WalkDir::new(source).follow_links(false).into_iter();
+
+        for entry in walker {
+            let entry = entry?;
+            let path = entry.path();
+
+            if !entry.metadata()?.is_file() {
+                continue;
+            }
+
+            let mut file = File::open(path)?;
+
+            let tail = path
+                .strip_prefix(source)
+                .map_err(|e| io::Error::new(io::ErrorKind::Other, e.to_string()))?;
+
+            let dest = append_components(dest_dir, tail)?;
+            self.push(&mut file, &dest, mode)?;
+        }
+
+        Ok(())
+    }
+
+    pub fn remove(&self, path: &UnixPath) -> Result<()> {
+        debug!("Deleting {}", path.display());
+
+        self.execute_host_shell_command_as(
+            &format!("rm -rf {}", path.display()),
+            self.enable_run_as_for_path(path),
+        )?;
+
+        Ok(())
+    }
+}
+
+pub(crate) fn append_components(
+    base: &UnixPath,
+    tail: &Path,
+) -> std::result::Result<UnixPathBuf, io::Error> {
+    let mut buf = base.to_path_buf();
+
+    for component in tail.components() {
+        if let Component::Normal(segment) = component {
+            let utf8 = segment.to_str().ok_or_else(|| {
+                io::Error::new(
+                    io::ErrorKind::Other,
+                    "Could not represent path segment as UTF-8",
+                )
+            })?;
+            buf.push(utf8);
+        } else {
+            return Err(io::Error::new(
+                io::ErrorKind::Other,
+                "Unexpected path component".to_owned(),
+            ));
+        }
+    }
+
+    Ok(buf)
+}
diff --git a/testing/mozbase/rust/mozdevice/src/shell.rs b/testing/mozbase/rust/mozdevice/src/shell.rs
new file mode 100644
index 0000000000..55a71c41d5
--- /dev/null
+++ b/testing/mozbase/rust/mozdevice/src/shell.rs
@@ -0,0 +1,66 @@
+// Copyright (c) 2017 Jimmy Cuadra
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+
+use regex::Regex;
+
+/// Escapes a string so it will be interpreted as a single word by the UNIX Bourne shell.
+///
+/// If the input string is empty, this function returns an empty quoted string.
+pub fn escape(input: &str) -> String {
+    // Stolen from
+    // https://docs.rs/shellwords/1.0.0/src/shellwords/lib.rs.html#24-37.
+    // Added space to the pattern to exclude spaces from being escaped
+    // which can cause problems when combining strings to form a full
+    // command.
+    let escape_pattern: Regex = Regex::new(r"([^A-Za-z0-9_\-.,:/@ \n])").unwrap();
+
+    if input.is_empty() {
+        return "''".to_owned();
+    }
+
+    let output = &escape_pattern.replace_all(input, "\\$1");
+
+    output.replace("'\n'", r"\n")
+}
+
+#[cfg(test)]
+mod tests {
+    use super::escape;
+
+    #[test]
+    fn empty_escape() {
+        assert_eq!(escape(""), "''");
+    }
+
+    #[test]
+    fn full_escape() {
+        assert_eq!(escape("foo '\"' bar"), "foo \\'\\\"\\' bar");
+    }
+
+    #[test]
+    fn escape_multibyte() {
+        assert_eq!(escape("あい"), "\\あ\\い");
+    }
+
+    #[test]
+    fn escape_newline() {
+        assert_eq!(escape(r"'\n'"), "\\\'\\\\n\\\'");
+    }
+}
diff --git a/testing/mozbase/rust/mozdevice/src/test.rs b/testing/mozbase/rust/mozdevice/src/test.rs
new file mode 100644
index 0000000000..b4173e3649
--- /dev/null
+++ b/testing/mozbase/rust/mozdevice/src/test.rs
@@ -0,0 +1,760 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// Currently the mozdevice API is not safe for multiple requests at the same
+// time. It is recommended to run each of the unit tests on its own. Also adb
+// specific tests cannot be run in CI yet. To check those locally, also run
+// the ignored tests.
+//
+// Use the following command to accomplish that:
+//
+//     $ cargo test -- --ignored --test-threads=1
+
+use crate::*;
+
+use std::collections::BTreeSet;
+use std::panic;
+use std::path::PathBuf;
+use tempfile::{tempdir, TempDir};
+
+#[test]
+fn read_length_from_valid_string() {
+    fn test(message: &str) -> Result<usize> {
+        read_length(&mut io::BufReader::new(message.as_bytes()))
+    }
+
+    assert_eq!(test("0000").unwrap(), 0);
+    assert_eq!(test("0001").unwrap(), 1);
+    assert_eq!(test("000F").unwrap(), 15);
+    assert_eq!(test("00FF").unwrap(), 255);
+    assert_eq!(test("0FFF").unwrap(), 4095);
+    assert_eq!(test("FFFF").unwrap(), 65535);
+
+    assert_eq!(test("FFFF0").unwrap(), 65535);
+}
+
+#[test]
+fn read_length_from_invalid_string() {
+    fn test(message: &str) -> Result<usize> {
+        read_length(&mut io::BufReader::new(message.as_bytes()))
+    }
+
+    test("").expect_err("empty string");
+    test("G").expect_err("invalid hex character");
+    test("-1").expect_err("negative number");
+    test("000").expect_err("shorter than 4 bytes");
+}
+
+#[test]
+fn encode_message_with_valid_string() {
+    assert_eq!(encode_message("").unwrap(), "0000".to_string());
+    assert_eq!(encode_message("a").unwrap(), "0001a".to_string());
+    assert_eq!(
+        encode_message(&"a".repeat(15)).unwrap(),
+        format!("000F{}", "a".repeat(15))
+    );
+    assert_eq!(
+        encode_message(&"a".repeat(255)).unwrap(),
+        format!("00FF{}", "a".repeat(255))
+    );
+    assert_eq!(
+        encode_message(&"a".repeat(4095)).unwrap(),
+        format!("0FFF{}", "a".repeat(4095))
+    );
+    assert_eq!(
+        encode_message(&"a".repeat(65535)).unwrap(),
+        format!("FFFF{}", "a".repeat(65535))
+    );
+}
+
+#[test]
+fn encode_message_with_invalid_string() {
+    encode_message(&"a".repeat(65536)).expect_err("string lengths exceeds 4 bytes");
+}
+
+fn run_device_test<F>(test: F)
+where
+    F: FnOnce(&Device, &TempDir, &UnixPath) + panic::UnwindSafe,
+{
+    let host = Host {
+        ..Default::default()
+    };
+    let device = host
+        .device_or_default::<String>(None, AndroidStorageInput::Auto)
+        .expect("device_or_default");
+
+    let tmp_dir = tempdir().expect("create temp dir");
+    let response = device
+        .execute_host_shell_command("echo $EXTERNAL_STORAGE")
+        .unwrap();
+    let mut test_root = UnixPathBuf::from(response.trim_end_matches('\n'));
+    test_root.push("mozdevice");
+
+    let _ = device.remove(&test_root);
+
+    let result = panic::catch_unwind(|| test(&device, &tmp_dir, &test_root));
+
+    let _ = device.kill_forward_all_ports();
+    // let _ = device.kill_reverse_all_ports();
+
+    assert!(result.is_ok())
+}
+
+#[test]
+#[ignore]
+fn host_features() {
+    let host = Host {
+        ..Default::default()
+    };
+
+    let set = host.features::<BTreeSet<_>>().expect("to query features");
+    assert!(set.contains("cmd"));
+    assert!(set.contains("shell_v2"));
+}
+
+#[test]
+#[ignore]
+fn host_devices() {
+    let host = Host {
+        ..Default::default()
+    };
+
+    let set: BTreeSet<_> = host.devices().expect("to query devices");
+    assert_eq!(1, set.len());
+}
+
+#[test]
+#[ignore]
+fn host_device_or_default() {
+    let host = Host {
+        ..Default::default()
+    };
+
+    let devices: Vec<_> = host.devices().expect("to query devices");
+    let expected_device = devices.first().expect("found a device");
+
+    let device = host
+        .device_or_default::<String>(Some(&expected_device.serial), AndroidStorageInput::App)
+        .expect("connected device with serial");
+    assert_eq!(device.run_as_package, None);
+    assert_eq!(device.serial, expected_device.serial);
+    assert!(device.tempfile.starts_with("/data/local/tmp"));
+}
+
+#[test]
+#[ignore]
+fn host_device_or_default_invalid_serial() {
+    let host = Host {
+        ..Default::default()
+    };
+
+    host.device_or_default::<String>(Some(&"foobar".to_owned()), AndroidStorageInput::Auto)
+        .expect_err("invalid serial");
+}
+
+#[test]
+#[ignore]
+fn host_device_or_default_no_serial() {
+    let host = Host {
+        ..Default::default()
+    };
+
+    let devices: Vec<_> = host.devices().expect("to query devices");
+    let expected_device = devices.first().expect("found a device");
+
+    let device = host
+        .device_or_default::<String>(None, AndroidStorageInput::Auto)
+        .expect("connected device with serial");
+    assert_eq!(device.serial, expected_device.serial);
+}
+
+#[test]
+#[ignore]
+fn host_device_or_default_storage_as_app() {
+    let host = Host {
+        ..Default::default()
+    };
+
+    let device = host
+        .device_or_default::<String>(None, AndroidStorageInput::App)
+        .expect("connected device");
+    assert_eq!(device.storage, AndroidStorage::App);
+}
+
+#[test]
+#[ignore]
+fn host_device_or_default_storage_as_auto() {
+    let host = Host {
+        ..Default::default()
+    };
+
+    let device = host
+        .device_or_default::<String>(None, AndroidStorageInput::Auto)
+        .expect("connected device");
+    assert_eq!(device.storage, AndroidStorage::Sdcard);
+}
+
+#[test]
+#[ignore]
+fn host_device_or_default_storage_as_internal() {
+    let host = Host {
+        ..Default::default()
+    };
+
+    let device = host
+        .device_or_default::<String>(None, AndroidStorageInput::Internal)
+        .expect("connected device");
+    assert_eq!(device.storage, AndroidStorage::Internal);
+}
+
+#[test]
+#[ignore]
+fn host_device_or_default_storage_as_sdcard() {
+    let host = Host {
+        ..Default::default()
+    };
+
+    let device = host
+        .device_or_default::<String>(None, AndroidStorageInput::Sdcard)
+        .expect("connected device");
+    assert_eq!(device.storage, AndroidStorage::Sdcard);
+}
+
+#[test]
+#[ignore]
+fn device_shell_command() {
+    run_device_test(|device: &Device, _: &TempDir, _: &UnixPath| {
+        assert_eq!(
+            "Linux\n",
+            device
+                .execute_host_shell_command("uname")
+                .expect("to have shell output")
+        );
+    });
+}
+
+#[test]
+#[ignore]
+fn device_forward_port_hardcoded() {
+    run_device_test(|device: &Device, _: &TempDir, _: &UnixPath| {
+        assert_eq!(
+            3035,
+            device
+                .forward_port(3035, 3036)
+                .expect("forwarded local port")
+        );
+        // TODO: check with forward --list
+    });
+}
+
+// #[test]
+// #[ignore]
+// TODO: "adb server response to `forward tcp:0 ...` was not a u16: \"000559464\"")
+// fn device_forward_port_system_allocated() {
+//     run_device_test(|device: &Device, _: &TempDir, _: &UnixPath| {
+//         let local_port = device.forward_port(0, 3037).expect("local_port");
+//         assert_ne!(local_port, 0);
+//         // TODO: check with forward --list
+//     });
+// }
+
+#[test]
+#[ignore]
+fn device_kill_forward_port_no_forwarded_port() {
+    run_device_test(|device: &Device, _: &TempDir, _: &UnixPath| {
+        device
+            .kill_forward_port(3038)
+            .expect_err("adb error: listener 'tcp:3038' ");
+    });
+}
+
+#[test]
+#[ignore]
+fn device_kill_forward_port_twice() {
+    run_device_test(|device: &Device, _: &TempDir, _: &UnixPath| {
+        let local_port = device
+            .forward_port(3039, 3040)
+            .expect("forwarded local port");
+        assert_eq!(local_port, 3039);
+        // TODO: check with forward --list
+        device
+            .kill_forward_port(local_port)
+            .expect("to remove forwarded port");
+        device
+            .kill_forward_port(local_port)
+            .expect_err("adb error: listener 'tcp:3039' ");
+    });
+}
+
+#[test]
+#[ignore]
+fn device_kill_forward_all_ports_no_forwarded_port() {
+    run_device_test(|device: &Device, _: &TempDir, _: &UnixPath| {
+        device
+            .kill_forward_all_ports()
+            .expect("to not fail for no forwarded ports");
+    });
+}
+
+#[test]
+#[ignore]
+fn device_kill_forward_all_ports_twice() {
+    run_device_test(|device: &Device, _: &TempDir, _: &UnixPath| {
+        let local_port1 = device
+            .forward_port(3039, 3040)
+            .expect("forwarded local port");
+        assert_eq!(local_port1, 3039);
+        let local_port2 = device
+            .forward_port(3041, 3042)
+            .expect("forwarded local port");
+        assert_eq!(local_port2, 3041);
+        // TODO: check with forward --list
+        device
+            .kill_forward_all_ports()
+            .expect("to remove all forwarded ports");
+        device
+            .kill_forward_all_ports()
+            .expect("to not fail for no forwarded ports");
+    });
+}
+
+#[test]
+#[ignore]
+fn device_reverse_port_hardcoded() {
+    run_device_test(|device: &Device, _: &TempDir, _: &UnixPath| {
+        assert_eq!(4035, device.reverse_port(4035, 4036).expect("remote_port"));
+        // TODO: check with reverse --list
+    });
+}
+
+// #[test]
+// #[ignore]
+// TODO: No adb response: ParseInt(ParseIntError { kind: Empty })
+// fn device_reverse_port_system_allocated() {
+//     run_device_test(|device: &Device, _: &TempDir, _: &UnixPath| {
+//         let reverse_port = device.reverse_port(0, 4037).expect("remote port");
+//         assert_ne!(reverse_port, 0);
+//         // TODO: check with reverse --list
+//     });
+// }
+
+#[test]
+#[ignore]
+fn device_kill_reverse_port_no_reverse_port() {
+    run_device_test(|device: &Device, _: &TempDir, _: &UnixPath| {
+        device
+            .kill_reverse_port(4038)
+            .expect_err("listener 'tcp:4038' not found");
+    });
+}
+
+// #[test]
+// #[ignore]
+// TODO: "adb error: adb server response did not contain expected hexstring length: \"\""
+// fn device_kill_reverse_port_twice() {
+//     run_device_test(|device: &Device, _: &TempDir, _: &UnixPath| {
+//         let remote_port = device
+//             .reverse_port(4039, 4040)
+//             .expect("reversed local port");
+//         assert_eq!(remote_port, 4039);
+//         // TODO: check with reverse --list
+//         device
+//             .kill_reverse_port(remote_port)
+//             .expect("to remove reverse port");
+//         device
+//             .kill_reverse_port(remote_port)
+//             .expect_err("listener 'tcp:4039' not found");
+//     });
+// }
+
+#[test]
+#[ignore]
+fn device_kill_reverse_all_ports_no_reversed_port() {
+    run_device_test(|device: &Device, _: &TempDir, _: &UnixPath| {
+        device
+            .kill_reverse_all_ports()
+            .expect("to not fail for no reversed ports");
+    });
+}
+
+#[test]
+#[ignore]
+fn device_kill_reverse_all_ports_twice() {
+    run_device_test(|device: &Device, _: &TempDir, _: &UnixPath| {
+        let local_port1 = device
+            .forward_port(4039, 4040)
+            .expect("forwarded local port");
+        assert_eq!(local_port1, 4039);
+        let local_port2 = device
+            .forward_port(4041, 4042)
+            .expect("forwarded local port");
+        assert_eq!(local_port2, 4041);
+        // TODO: check with reverse --list
+        device
+            .kill_reverse_all_ports()
+            .expect("to remove all reversed ports");
+        device
+            .kill_reverse_all_ports()
+            .expect("to not fail for no reversed ports");
+    });
+}
+
+#[test]
+#[ignore]
+fn device_push_pull_text_file() {
+    run_device_test(
+        |device: &Device, _: &TempDir, remote_root_path: &UnixPath| {
+            let content = "test";
+            let remote_path = remote_root_path.join("foo.txt");
+
+            device
+                .push(
+                    &mut io::BufReader::new(content.as_bytes()),
+                    &remote_path,
+                    0o777,
+                )
+                .expect("file has been pushed");
+
+            let file_content = device
+                .execute_host_shell_command(&format!("cat {}", remote_path.display()))
+                .expect("host shell command for 'cat' to succeed");
+
+            assert_eq!(file_content, content);
+
+            // And as second step pull it off the device.
+            let mut buffer = Vec::new();
+            device
+                .pull(&remote_path, &mut buffer)
+                .expect("file has been pulled");
+            assert_eq!(buffer, content.as_bytes());
+        },
+    );
+}
+
+#[test]
+#[ignore]
+fn device_push_pull_large_binary_file() {
+    run_device_test(
+        |device: &Device, _: &TempDir, remote_root_path: &UnixPath| {
+            let remote_path = remote_root_path.join("foo.binary");
+
+            let mut content = Vec::new();
+
+            // Needs to be larger than 64kB to test multiple chunks.
+            for i in 0..100000u32 {
+                content.push('0' as u8 + (i % 10) as u8);
+            }
+
+            device
+                .push(
+                    &mut std::io::Cursor::new(content.clone()),
+                    &remote_path,
+                    0o777,
+                )
+                .expect("large file has been pushed");
+
+            let output = device
+                .execute_host_shell_command(&format!("ls -l {}", remote_path.display()))
+                .expect("host shell command for 'ls' to succeed");
+
+            assert!(output.contains(remote_path.to_str().unwrap()));
+
+            let mut buffer = Vec::new();
+
+            device
+                .pull(&remote_path, &mut buffer)
+                .expect("large binary file has been pulled");
+            assert_eq!(buffer, content);
+        },
+    );
+}
+
+#[test]
+#[ignore]
+fn device_push_permission() {
+    run_device_test(
+        |device: &Device, _: &TempDir, remote_root_path: &UnixPath| {
+            fn adjust_mode(mode: u32) -> u32 {
+                // Adjust the mode by copying the user permissions to
+                // group and other as indicated in
+                // [send_impl](https://android.googlesource.com/platform/system/core/+/master/adb/daemon/file_sync_service.cpp#516).
+                // This ensures that group and other can both access a
+                // file if the user can access it.
+                let mut m = mode & 0o777;
+                m |= (m >> 3) & 0o070;
+                m |= (m >> 3) & 0o007;
+                m
+            }
+
+            fn get_permissions(mode: u32) -> String {
+                // Convert the mode integer into the string representation
+                // of the mode returned by `ls`. This assumes the object is
+                // a file and not a directory.
+                let mut perms = vec!["-", "r", "w", "x", "r", "w", "x", "r", "w", "x"];
+                let mut bit_pos = 0;
+                while bit_pos < 9 {
+                    if (1 << bit_pos) & mode == 0 {
+                        perms[9 - bit_pos] = "-"
+                    }
+                    bit_pos += 1;
+                }
+                perms.concat()
+            }
+            let content = "test";
+            let remote_path = remote_root_path.join("foo.bar");
+
+            // First push the file to the device
+            let modes = vec![0o421, 0o644, 0o666, 0o777];
+            for mode in modes {
+                let adjusted_mode = adjust_mode(mode);
+                let adjusted_perms = get_permissions(adjusted_mode);
+                device
+                    .push(
+                        &mut io::BufReader::new(content.as_bytes()),
+                        &remote_path,
+                        mode,
+                    )
+                    .expect("file has been pushed");
+
+                let output = device
+                    .execute_host_shell_command(&format!("ls -l {}", remote_path.display()))
+                    .expect("host shell command for 'ls' to succeed");
+
+                assert!(output.contains(remote_path.to_str().unwrap()));
+                assert!(output.starts_with(&adjusted_perms));
+            }
+
+            let output = device
+                .execute_host_shell_command(&format!("ls -ld {}", remote_root_path.display()))
+                .expect("host shell command for 'ls parent' to succeed");
+
+            assert!(output.contains(remote_root_path.to_str().unwrap()));
+            assert!(output.starts_with("drwxrwxrwx"));
+        },
+    );
+}
+
+#[test]
+#[ignore]
+fn device_pull_fails_for_missing_file() {
+    run_device_test(
+        |device: &Device, _: &TempDir, remote_root_path: &UnixPath| {
+            let mut buffer = Vec::new();
+
+            device
+                .pull(&remote_root_path.join("missing"), &mut buffer)
+                .expect_err("missing file should not be pulled");
+        },
+    );
+}
+
+#[test]
+#[ignore]
+fn device_push_and_list_dir() {
+    run_device_test(
+        |device: &Device, tmp_dir: &TempDir, remote_root_path: &UnixPath| {
+            let files = ["foo1.bar", "foo2.bar", "bar/foo3.bar", "bar/more/foo3.bar"];
+
+            for file in files.iter() {
+                let path = tmp_dir.path().join(Path::new(file));
+                let _ = std::fs::create_dir_all(path.parent().unwrap());
+
+                let f = File::create(path).expect("to create file");
+                let mut f = io::BufWriter::new(f);
+                f.write_all(file.as_bytes()).expect("to write data");
+            }
+
+            device
+                .push_dir(tmp_dir.path(), &remote_root_path, 0o777)
+                .expect("to push_dir");
+
+            for file in files.iter() {
+                let path = append_components(remote_root_path, Path::new(file)).unwrap();
+                let output = device
+                    .execute_host_shell_command(&format!("ls {}", path.display()))
+                    .expect("host shell command for 'ls' to succeed");
+
+                assert!(output.contains(path.to_str().unwrap()));
+            }
+
+            let mut listings = device.list_dir(&remote_root_path).expect("to list_dir");
+            listings.sort();
+            assert_eq!(
+                listings,
+                vec![
+                    RemoteDirEntry {
+                        depth: 0,
+                        name: "foo1.bar".to_string(),
+                        metadata: RemoteMetadata::RemoteFile(RemoteFileMetadata {
+                            mode: 0b110110000,
+                            size: 8
+                        })
+                    },
+                    RemoteDirEntry {
+                        depth: 0,
+                        name: "foo2.bar".to_string(),
+                        metadata: RemoteMetadata::RemoteFile(RemoteFileMetadata {
+                            mode: 0b110110000,
+                            size: 8
+                        })
+                    },
+                    RemoteDirEntry {
+                        depth: 0,
+                        name: "bar".to_string(),
+                        metadata: RemoteMetadata::RemoteDir
+                    },
+                    RemoteDirEntry {
+                        depth: 1,
+                        name: "bar/foo3.bar".to_string(),
+                        metadata: RemoteMetadata::RemoteFile(RemoteFileMetadata {
+                            mode: 0b110110000,
+                            size: 12
+                        })
+                    },
+                    RemoteDirEntry {
+                        depth: 1,
+                        name: "bar/more".to_string(),
+                        metadata: RemoteMetadata::RemoteDir
+                    },
+                    RemoteDirEntry {
+                        depth: 2,
+                        name: "bar/more/foo3.bar".to_string(),
+                        metadata: RemoteMetadata::RemoteFile(RemoteFileMetadata {
+                            mode: 0b110110000,
+                            size: 17
+                        })
+                    }
+                ]
+            );
+        },
+    );
+}
+
+#[test]
+#[ignore]
+fn device_push_and_pull_dir() {
+    run_device_test(
+        |device: &Device, tmp_dir: &TempDir, remote_root_path: &UnixPath| {
+            let files = ["foo1.bar", "foo2.bar", "bar/foo3.bar", "bar/more/foo3.bar"];
+
+            let src_dir = tmp_dir.path().join(Path::new("src"));
+            let dest_dir = tmp_dir.path().join(Path::new("src"));
+
+            for file in files.iter() {
+                let path = src_dir.join(Path::new(file));
+                let _ = std::fs::create_dir_all(path.parent().unwrap());
+
+                let f = File::create(path).expect("to create file");
+                let mut f = io::BufWriter::new(f);
+                f.write_all(file.as_bytes()).expect("to write data");
+            }
+
+            device
+                .push_dir(&src_dir, &remote_root_path, 0o777)
+                .expect("to push_dir");
+
+            device
+                .pull_dir(remote_root_path, &dest_dir)
+                .expect("to pull_dir");
+
+            for file in files.iter() {
+                let path = dest_dir.join(Path::new(file));
+                let mut f = File::open(path).expect("to open file");
+                let mut buf = String::new();
+                f.read_to_string(&mut buf).expect("to read content");
+                assert_eq!(buf, *file);
+            }
+        },
+    )
+}
+
+#[test]
+#[ignore]
+fn device_push_and_list_dir_flat() {
+    run_device_test(
+        |device: &Device, tmp_dir: &TempDir, remote_root_path: &UnixPath| {
+            let content = "test";
+
+            let files = [
+                PathBuf::from("foo1.bar"),
+                PathBuf::from("foo2.bar"),
+                PathBuf::from("bar").join("foo3.bar"),
+            ];
+
+            for file in files.iter() {
+                let path = tmp_dir.path().join(&file);
+                let _ = std::fs::create_dir_all(path.parent().unwrap());
+
+                let f = File::create(path).expect("to create file");
+                let mut f = io::BufWriter::new(f);
+                f.write_all(content.as_bytes()).expect("to write data");
+            }
+
+            device
+                .push_dir(tmp_dir.path(), &remote_root_path, 0o777)
+                .expect("to push_dir");
+
+            for file in files.iter() {
+                let path = append_components(remote_root_path, file).unwrap();
+                let output = device
+                    .execute_host_shell_command(&format!("ls {}", path.display()))
+                    .expect("host shell command for 'ls' to succeed");
+
+                assert!(output.contains(path.to_str().unwrap()));
+            }
+
+            let mut listings = device
+                .list_dir_flat(&remote_root_path, 7, "prefix".to_string())
+                .expect("to list_dir_flat");
+            listings.sort();
+            assert_eq!(
+                listings,
+                vec![
+                    RemoteDirEntry {
+                        depth: 7,
+                        metadata: RemoteMetadata::RemoteFile(RemoteFileMetadata {
+                            mode: 0b110110000,
+                            size: 4
+                        }),
+                        name: "prefix/foo1.bar".to_string(),
+                    },
+                    RemoteDirEntry {
+                        depth: 7,
+                        metadata: RemoteMetadata::RemoteFile(RemoteFileMetadata {
+                            mode: 0b110110000,
+                            size: 4
+                        }),
+                        name: "prefix/foo2.bar".to_string(),
+                    },
+                    RemoteDirEntry {
+                        depth: 7,
+                        metadata: RemoteMetadata::RemoteDir,
+                        name: "prefix/bar".to_string(),
+                    },
+                ]
+            );
+        },
+    );
+}
+
+#[test]
+fn format_own_device_error_types() {
+    assert_eq!(
+        format!("{}", DeviceError::InvalidStorage),
+        "Invalid storage".to_string()
+    );
+    assert_eq!(
+        format!("{}", DeviceError::MissingPackage),
+        "Missing package".to_string()
+    );
+    assert_eq!(
+        format!("{}", DeviceError::MultipleDevices),
+        "Multiple Android devices online".to_string()
+    );
+
+    assert_eq!(
+        format!("{}", DeviceError::Adb("foo".to_string())),
+        "foo".to_string()
+    );
+}
diff --git a/testing/mozbase/rust/mozprofile/Cargo.toml b/testing/mozbase/rust/mozprofile/Cargo.toml
new file mode 100644
index 0000000000..17920885bf
--- /dev/null
+++ b/testing/mozbase/rust/mozprofile/Cargo.toml
@@ -0,0 +1,15 @@
+[package]
+edition = "2018"
+name = "mozprofile"
+version = "0.9.0"
+authors = ["Mozilla"]
+description = "Library for working with Mozilla profiles."
+keywords = [
+    "firefox",
+    "mozilla",
+]
+license = "MPL-2.0"
+repository = "https://hg.mozilla.org/mozilla-central/file/tip/testing/mozbase/rust/mozprofile"
+
+[dependencies]
+tempfile = "3"
diff --git a/testing/mozbase/rust/mozprofile/fuzz/Cargo.toml b/testing/mozbase/rust/mozprofile/fuzz/Cargo.toml
new file mode 100644
index 0000000000..53e116143c
--- /dev/null
+++ b/testing/mozbase/rust/mozprofile/fuzz/Cargo.toml
@@ -0,0 +1,25 @@
+[package]
+name = "mozprofile-fuzz"
+version = "0.0.0"
+authors = ["Automatically generated"]
+publish = false
+edition = "2018"
+
+[package.metadata]
+cargo-fuzz = true
+
+[dependencies]
+libfuzzer-sys = "0.4"
+
+[dependencies.mozprofile]
+path = ".."
+
+# Prevent this from interfering with workspaces
+[workspace]
+members = ["."]
+
+[[bin]]
+name = "prefreader"
+path = "fuzz_targets/prefreader.rs"
+test = false
+doc = false
diff --git a/testing/mozbase/rust/mozprofile/fuzz/fuzz_targets/prefreader.rs b/testing/mozbase/rust/mozprofile/fuzz/fuzz_targets/prefreader.rs
new file mode 100644
index 0000000000..824eb3c31e
--- /dev/null
+++ b/testing/mozbase/rust/mozprofile/fuzz/fuzz_targets/prefreader.rs
@@ -0,0 +1,16 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#![no_main]
+use libfuzzer_sys::fuzz_target;
+use std::io::Cursor;
+extern crate mozprofile;
+
+fuzz_target!(|data: &[u8]| {
+    let buf = Vec::new();
+    let mut out = Cursor::new(buf);
+    mozprofile::prefreader::parse(data).map(|parsed| {
+        mozprofile::prefreader::serialize(&parsed, &mut out);
+    });
+});
diff --git a/testing/mozbase/rust/mozprofile/src/lib.rs b/testing/mozbase/rust/mozprofile/src/lib.rs
new file mode 100644
index 0000000000..346f291137
--- /dev/null
+++ b/testing/mozbase/rust/mozprofile/src/lib.rs
@@ -0,0 +1,241 @@
+#![forbid(unsafe_code)]
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+extern crate tempfile;
+
+pub mod preferences;
+pub mod prefreader;
+pub mod profile;
+
+#[cfg(test)]
+mod test {
+    //    use std::fs::File;
+    //    use profile::Profile;
+    use crate::preferences::Pref;
+    use crate::prefreader::{parse, serialize, tokenize};
+    use crate::prefreader::{Position, PrefToken};
+    use std::collections::BTreeMap;
+    use std::io::Cursor;
+    use std::str;
+
+    #[test]
+    fn tokenize_simple() {
+        let prefs = "  user_pref ( 'example.pref.string', 'value' )   ;\n \
+                     pref(\"example.pref.int\", -123); sticky_pref('example.pref.bool',false);";
+
+        let p = Position::new();
+
+        let expected = vec![
+            PrefToken::UserPrefFunction(p),
+            PrefToken::Paren('(', p),
+            PrefToken::String("example.pref.string".into(), p),
+            PrefToken::Comma(p),
+            PrefToken::String("value".into(), p),
+            PrefToken::Paren(')', p),
+            PrefToken::Semicolon(p),
+            PrefToken::PrefFunction(p),
+            PrefToken::Paren('(', p),
+            PrefToken::String("example.pref.int".into(), p),
+            PrefToken::Comma(p),
+            PrefToken::Int(-123, p),
+            PrefToken::Paren(')', p),
+            PrefToken::Semicolon(p),
+            PrefToken::StickyPrefFunction(p),
+            PrefToken::Paren('(', p),
+            PrefToken::String("example.pref.bool".into(), p),
+            PrefToken::Comma(p),
+            PrefToken::Bool(false, p),
+            PrefToken::Paren(')', p),
+            PrefToken::Semicolon(p),
+        ];
+
+        tokenize_test(prefs, &expected);
+    }
+
+    #[test]
+    fn tokenize_comments() {
+        let prefs = "# bash style comment\n /*block comment*/ user_pref/*block comment*/(/*block \
+                     comment*/ 'example.pref.string'  /*block comment*/,/*block comment*/ \
+                     'value'/*block comment*/ )// line comment";
+
+        let p = Position::new();
+
+        let expected = vec![
+            PrefToken::CommentBashLine(" bash style comment".into(), p),
+            PrefToken::CommentBlock("block comment".into(), p),
+            PrefToken::UserPrefFunction(p),
+            PrefToken::CommentBlock("block comment".into(), p),
+            PrefToken::Paren('(', p),
+            PrefToken::CommentBlock("block comment".into(), p),
+            PrefToken::String("example.pref.string".into(), p),
+            PrefToken::CommentBlock("block comment".into(), p),
+            PrefToken::Comma(p),
+            PrefToken::CommentBlock("block comment".into(), p),
+            PrefToken::String("value".into(), p),
+            PrefToken::CommentBlock("block comment".into(), p),
+            PrefToken::Paren(')', p),
+            PrefToken::CommentLine(" line comment".into(), p),
+        ];
+
+        tokenize_test(prefs, &expected);
+    }
+
+    #[test]
+    fn tokenize_escapes() {
+        let prefs = r#"user_pref('example\x20pref', "\u0020\u2603\uD800\uDC96\"\'\n\r\\\w)"#;
+
+        let p = Position::new();
+
+        let expected = vec![
+            PrefToken::UserPrefFunction(p),
+            PrefToken::Paren('(', p),
+            PrefToken::String("example pref".into(), p),
+            PrefToken::Comma(p),
+            PrefToken::String(" ☃𐂖\"'\n\r\\\\w".into(), p),
+            PrefToken::Paren(')', p),
+        ];
+
+        tokenize_test(prefs, &expected);
+    }
+
+    fn tokenize_test(prefs: &str, expected: &[PrefToken]) {
+        println!("{}\n", prefs);
+
+        for (e, a) in expected.iter().zip(tokenize(prefs.as_bytes())) {
+            let success = match (e, &a) {
+                (&PrefToken::PrefFunction(_), &PrefToken::PrefFunction(_)) => true,
+                (&PrefToken::UserPrefFunction(_), &PrefToken::UserPrefFunction(_)) => true,
+                (&PrefToken::StickyPrefFunction(_), &PrefToken::StickyPrefFunction(_)) => true,
+                (
+                    &PrefToken::CommentBlock(ref data_e, _),
+                    &PrefToken::CommentBlock(ref data_a, _),
+                ) => data_e == data_a,
+                (
+                    &PrefToken::CommentLine(ref data_e, _),
+                    &PrefToken::CommentLine(ref data_a, _),
+                ) => data_e == data_a,
+                (
+                    &PrefToken::CommentBashLine(ref data_e, _),
+                    &PrefToken::CommentBashLine(ref data_a, _),
+                ) => data_e == data_a,
+                (&PrefToken::Paren(data_e, _), &PrefToken::Paren(data_a, _)) => data_e == data_a,
+                (&PrefToken::Semicolon(_), &PrefToken::Semicolon(_)) => true,
+                (&PrefToken::Comma(_), &PrefToken::Comma(_)) => true,
+                (&PrefToken::String(ref data_e, _), &PrefToken::String(ref data_a, _)) => {
+                    data_e == data_a
+                }
+                (&PrefToken::Int(data_e, _), &PrefToken::Int(data_a, _)) => data_e == data_a,
+                (&PrefToken::Bool(data_e, _), &PrefToken::Bool(data_a, _)) => data_e == data_a,
+                (&PrefToken::Error(ref data_e, _), &PrefToken::Error(ref data_a, _)) => {
+                    *data_e == *data_a
+                }
+                (_, _) => false,
+            };
+            if !success {
+                println!("Expected {:?}, got {:?}", e, a);
+            }
+            assert!(success);
+        }
+    }
+
+    #[test]
+    fn parse_simple() {
+        let input = "  user_pref /* block comment */ ( 'example.pref.string', 'value' )   ;\n \
+                     pref(\"example.pref.int\", -123); sticky_pref('example.pref.bool',false)";
+
+        let mut expected: BTreeMap<String, Pref> = BTreeMap::new();
+        expected.insert("example.pref.string".into(), Pref::new("value"));
+        expected.insert("example.pref.int".into(), Pref::new(-123));
+        expected.insert("example.pref.bool".into(), Pref::new_sticky(false));
+
+        parse_test(input, expected);
+    }
+
+    #[test]
+    fn parse_escape() {
+        let input = r#"user_pref('example\\pref\"string', 'val\x20ue' )"#;
+
+        let mut expected: BTreeMap<String, Pref> = BTreeMap::new();
+        expected.insert("example\\pref\"string".into(), Pref::new("val ue"));
+
+        parse_test(input, expected);
+    }
+
+    #[test]
+    fn parse_empty() {
+        let inputs = ["", " ", "\n", "\n \n"];
+        for input in inputs {
+            let expected: BTreeMap<String, Pref> = BTreeMap::new();
+            parse_test(input, expected);
+        }
+    }
+
+    #[test]
+    fn parse_newline() {
+        let inputs = vec!["\na", "\n\nfoo"];
+        for input in inputs {
+            assert!(parse(input.as_bytes()).is_err());
+        }
+    }
+
+    #[test]
+    fn parse_minus() {
+        let inputs = ["pref(-", "user_pref(\"example.pref.int\", -);"];
+        for input in inputs {
+            assert!(parse(input.as_bytes()).is_err());
+        }
+    }
+
+    #[test]
+    fn parse_boolean_eof() {
+        let inputs = vec!["pref(true", "pref(false", "pref(false,", "pref(false)"];
+        for input in inputs {
+            assert!(parse(input.as_bytes()).is_err());
+        }
+    }
+
+    fn parse_test(input: &str, expected: BTreeMap<String, Pref>) {
+        match parse(input.as_bytes()) {
+            Ok(ref actual) => {
+                println!("Expected:\n{:?}\nActual\n{:?}", expected, actual);
+                assert_eq!(actual, &expected);
+            }
+            Err(e) => {
+                println!("{}", e);
+                assert!(false)
+            }
+        }
+    }
+
+    #[test]
+    fn serialize_simple() {
+        let input = "  user_pref /* block comment */ ( 'example.pref.string', 'value' )   ;\n \
+                     pref(\"example.pref.int\", -123); sticky_pref('example.pref.bool',false)";
+        let expected = "sticky_pref(\"example.pref.bool\", false);
+user_pref(\"example.pref.int\", -123);
+user_pref(\"example.pref.string\", \"value\");\n";
+
+        serialize_test(input, expected);
+    }
+
+    #[test]
+    fn serialize_quotes() {
+        let input = r#"user_pref('example\\with"quotes"', '"Value"')"#;
+        let expected = r#"user_pref("example\\with\"quotes\"", "\"Value\"");
+"#;
+
+        serialize_test(input, expected);
+    }
+
+    fn serialize_test(input: &str, expected: &str) {
+        let buf = Vec::with_capacity(expected.len());
+        let mut out = Cursor::new(buf);
+        serialize(&parse(input.as_bytes()).unwrap(), &mut out).unwrap();
+        let data = out.into_inner();
+        let actual = str::from_utf8(&*data).unwrap();
+        println!("Expected:\n{:?}\nActual\n{:?}", expected, actual);
+        assert_eq!(actual, expected);
+    }
+}
diff --git a/testing/mozbase/rust/mozprofile/src/preferences.rs b/testing/mozbase/rust/mozprofile/src/preferences.rs
new file mode 100644
index 0000000000..2489352384
--- /dev/null
+++ b/testing/mozbase/rust/mozprofile/src/preferences.rs
@@ -0,0 +1,138 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+use std::collections::BTreeMap;
+
+pub type Preferences = BTreeMap<String, Pref>;
+
+#[derive(Debug, PartialEq, Clone)]
+pub enum PrefValue {
+    Bool(bool),
+    String(String),
+    Int(i64),
+}
+
+impl From<bool> for PrefValue {
+    fn from(value: bool) -> Self {
+        PrefValue::Bool(value)
+    }
+}
+
+impl From<String> for PrefValue {
+    fn from(value: String) -> Self {
+        PrefValue::String(value)
+    }
+}
+
+impl From<&'static str> for PrefValue {
+    fn from(value: &'static str) -> Self {
+        PrefValue::String(value.into())
+    }
+}
+
+impl From<i8> for PrefValue {
+    fn from(value: i8) -> Self {
+        PrefValue::Int(value.into())
+    }
+}
+
+impl From<u8> for PrefValue {
+    fn from(value: u8) -> Self {
+        PrefValue::Int(value.into())
+    }
+}
+
+impl From<i16> for PrefValue {
+    fn from(value: i16) -> Self {
+        PrefValue::Int(value.into())
+    }
+}
+
+impl From<u16> for PrefValue {
+    fn from(value: u16) -> Self {
+        PrefValue::Int(value.into())
+    }
+}
+
+impl From<i32> for PrefValue {
+    fn from(value: i32) -> Self {
+        PrefValue::Int(value.into())
+    }
+}
+
+impl From<u32> for PrefValue {
+    fn from(value: u32) -> Self {
+        PrefValue::Int(value.into())
+    }
+}
+
+impl From<i64> for PrefValue {
+    fn from(value: i64) -> Self {
+        PrefValue::Int(value)
+    }
+}
+
+// Implementing From<u64> for PrefValue wouldn't be safe
+// because it might overflow.
+
+#[derive(Debug, PartialEq, Clone)]
+pub struct Pref {
+    pub value: PrefValue,
+    pub sticky: bool,
+}
+
+impl Pref {
+    /// Create a new preference with `value`.
+    pub fn new<T>(value: T) -> Pref
+    where
+        T: Into<PrefValue>,
+    {
+        Pref {
+            value: value.into(),
+            sticky: false,
+        }
+    }
+
+    /// Create a new sticky, or locked, preference with `value`.
+    /// These cannot be changed by the user in `about:config`.
+    pub fn new_sticky<T>(value: T) -> Pref
+    where
+        T: Into<PrefValue>,
+    {
+        Pref {
+            value: value.into(),
+            sticky: true,
+        }
+    }
+}
+
+#[cfg(test)]
+mod test {
+    use super::PrefValue;
+
+    #[test]
+    fn test_bool() {
+        assert_eq!(PrefValue::from(true), PrefValue::Bool(true));
+    }
+
+    #[test]
+    fn test_string() {
+        assert_eq!(PrefValue::from("foo"), PrefValue::String("foo".to_string()));
+        assert_eq!(
+            PrefValue::from("foo".to_string()),
+            PrefValue::String("foo".to_string())
+        );
+    }
+
+    #[test]
+    fn test_int() {
+        assert_eq!(PrefValue::from(42i8), PrefValue::Int(42i64));
+        assert_eq!(PrefValue::from(42u8), PrefValue::Int(42i64));
+        assert_eq!(PrefValue::from(42i16), PrefValue::Int(42i64));
+        assert_eq!(PrefValue::from(42u16), PrefValue::Int(42i64));
+        assert_eq!(PrefValue::from(42i32), PrefValue::Int(42i64));
+        assert_eq!(PrefValue::from(42u32), PrefValue::Int(42i64));
+        assert_eq!(PrefValue::from(42i64), PrefValue::Int(42i64));
+    }
+}
diff --git a/testing/mozbase/rust/mozprofile/src/prefreader.rs b/testing/mozbase/rust/mozprofile/src/prefreader.rs
new file mode 100644
index 0000000000..cff3edb617
--- /dev/null
+++ b/testing/mozbase/rust/mozprofile/src/prefreader.rs
@@ -0,0 +1,1064 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+use crate::preferences::{Pref, PrefValue, Preferences};
+use std::borrow::Borrow;
+use std::borrow::Cow;
+use std::char;
+use std::error::Error;
+use std::fmt;
+use std::io::{self, Write};
+use std::iter::Iterator;
+use std::mem;
+use std::str;
+
+impl PrefReaderError {
+    fn new(message: String, position: Position, parent: Option<Box<dyn Error>>) -> PrefReaderError {
+        PrefReaderError {
+            message,
+            position,
+            parent,
+        }
+    }
+}
+
+impl fmt::Display for PrefReaderError {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(
+            f,
+            "{} at line {}, column {}",
+            self.message, self.position.line, self.position.column
+        )
+    }
+}
+
+impl Error for PrefReaderError {
+    fn description(&self) -> &str {
+        &self.message
+    }
+
+    fn cause(&self) -> Option<&dyn Error> {
+        self.parent.as_deref()
+    }
+}
+
+impl From<io::Error> for PrefReaderError {
+    fn from(err: io::Error) -> PrefReaderError {
+        PrefReaderError::new("IOError".into(), Position::new(), Some(err.into()))
+    }
+}
+
+#[derive(Copy, Clone, Debug, PartialEq)]
+enum TokenizerState {
+    Junk,
+    CommentStart,
+    CommentLine,
+    CommentBlock,
+    FunctionName,
+    AfterFunctionName,
+    FunctionArgs,
+    FunctionArg,
+    DoubleQuotedString,
+    SingleQuotedString,
+    Number,
+    Bool,
+    AfterFunctionArg,
+    AfterFunction,
+    Error,
+}
+
+#[derive(Copy, Clone, Debug, Default, PartialEq)]
+pub struct Position {
+    line: u32,
+    column: u32,
+}
+
+impl Position {
+    pub fn new() -> Position {
+        Position { line: 1, column: 0 }
+    }
+}
+
+#[derive(Copy, Clone, Debug, PartialEq)]
+pub enum TokenType {
+    None,
+    PrefFunction,
+    UserPrefFunction,
+    StickyPrefFunction,
+    CommentBlock,
+    CommentLine,
+    CommentBashLine,
+    Paren,
+    Semicolon,
+    Comma,
+    String,
+    Int,
+    Bool,
+    Error,
+}
+
+#[derive(Debug, PartialEq)]
+pub enum PrefToken<'a> {
+    PrefFunction(Position),
+    UserPrefFunction(Position),
+    StickyPrefFunction(Position),
+    CommentBlock(Cow<'a, str>, Position),
+    CommentLine(Cow<'a, str>, Position),
+    CommentBashLine(Cow<'a, str>, Position),
+    Paren(char, Position),
+    Semicolon(Position),
+    Comma(Position),
+    String(Cow<'a, str>, Position),
+    Int(i64, Position),
+    Bool(bool, Position),
+    Error(String, Position),
+}
+
+impl<'a> PrefToken<'a> {
+    fn position(&self) -> Position {
+        match *self {
+            PrefToken::PrefFunction(position) => position,
+            PrefToken::UserPrefFunction(position) => position,
+            PrefToken::StickyPrefFunction(position) => position,
+            PrefToken::CommentBlock(_, position) => position,
+            PrefToken::CommentLine(_, position) => position,
+            PrefToken::CommentBashLine(_, position) => position,
+            PrefToken::Paren(_, position) => position,
+            PrefToken::Semicolon(position) => position,
+            PrefToken::Comma(position) => position,
+            PrefToken::String(_, position) => position,
+            PrefToken::Int(_, position) => position,
+            PrefToken::Bool(_, position) => position,
+            PrefToken::Error(_, position) => position,
+        }
+    }
+}
+
+#[derive(Debug)]
+pub struct PrefReaderError {
+    message: String,
+    position: Position,
+    parent: Option<Box<dyn Error>>,
+}
+
+struct TokenData<'a> {
+    token_type: TokenType,
+    complete: bool,
+    position: Position,
+    data: Cow<'a, str>,
+    start_pos: usize,
+}
+
+impl<'a> TokenData<'a> {
+    fn new(token_type: TokenType, position: Position, start_pos: usize) -> TokenData<'a> {
+        TokenData {
+            token_type,
+            complete: false,
+            position,
+            data: Cow::Borrowed(""),
+            start_pos,
+        }
+    }
+
+    fn start(&mut self, tokenizer: &PrefTokenizer, token_type: TokenType) {
+        self.token_type = token_type;
+        self.position = tokenizer.position;
+        self.start_pos = tokenizer.pos;
+    }
+
+    fn end(&mut self, buf: &'a [u8], end_pos: usize) -> Result<(), PrefReaderError> {
+        self.complete = true;
+        self.add_slice_to_token(buf, end_pos)
+    }
+
+    fn add_slice_to_token(&mut self, buf: &'a [u8], end_pos: usize) -> Result<(), PrefReaderError> {
+        let data = match str::from_utf8(&buf[self.start_pos..end_pos]) {
+            Ok(x) => x,
+            Err(_) => {
+                return Err(PrefReaderError::new(
+                    "Could not convert string to utf8".into(),
+                    self.position,
+                    None,
+                ));
+            }
+        };
+        if self.data != "" {
+            self.data.to_mut().push_str(data)
+        } else {
+            self.data = Cow::Borrowed(data)
+        };
+        Ok(())
+    }
+
+    fn push_char(&mut self, tokenizer: &PrefTokenizer, data: char) {
+        self.data.to_mut().push(data);
+        self.start_pos = tokenizer.pos + 1;
+    }
+}
+
+pub struct PrefTokenizer<'a> {
+    data: &'a [u8],
+    pos: usize,
+    cur: Option<char>,
+    position: Position,
+    state: TokenizerState,
+    next_state: Option<TokenizerState>,
+}
+
+impl<'a> PrefTokenizer<'a> {
+    pub fn new(data: &'a [u8]) -> PrefTokenizer<'a> {
+        PrefTokenizer {
+            data,
+            pos: 0,
+            cur: None,
+            position: Position::new(),
+            state: TokenizerState::Junk,
+            next_state: Some(TokenizerState::FunctionName),
+        }
+    }
+
+    fn make_token(&mut self, token_data: TokenData<'a>) -> PrefToken<'a> {
+        let buf = token_data.data;
+        let position = token_data.position;
+        // Note: the panic! here are for cases where the invalid input is regarded as
+        // a bug in the caller. In cases where `make_token` can legitimately be called
+        // with invalid data we must instead return a PrefToken::Error
+        match token_data.token_type {
+            TokenType::None => panic!("Got a token without a type"),
+            TokenType::PrefFunction => PrefToken::PrefFunction(position),
+            TokenType::UserPrefFunction => PrefToken::UserPrefFunction(position),
+            TokenType::StickyPrefFunction => PrefToken::StickyPrefFunction(position),
+            TokenType::CommentBlock => PrefToken::CommentBlock(buf, position),
+            TokenType::CommentLine => PrefToken::CommentLine(buf, position),
+            TokenType::CommentBashLine => PrefToken::CommentBashLine(buf, position),
+            TokenType::Paren => {
+                if buf.len() != 1 {
+                    panic!("Expected a buffer of length one");
+                }
+                PrefToken::Paren(buf.chars().next().unwrap(), position)
+            }
+            TokenType::Semicolon => PrefToken::Semicolon(position),
+            TokenType::Comma => PrefToken::Comma(position),
+            TokenType::String => PrefToken::String(buf, position),
+            TokenType::Int => {
+                return match buf.parse::<i64>() {
+                    Ok(value) => PrefToken::Int(value, position),
+                    Err(_) => PrefToken::Error(format!("Expected integer, got {}", buf), position),
+                }
+            }
+            TokenType::Bool => {
+                let value = match buf.borrow() {
+                    "true" => true,
+                    "false" => false,
+                    x => panic!("Boolean wasn't 'true' or 'false' (was {})", x),
+                };
+                PrefToken::Bool(value, position)
+            }
+            TokenType::Error => panic!("make_token can't construct errors"),
+        }
+    }
+
+    fn get_char(&mut self) -> Option<char> {
+        if self.pos + 1 >= self.data.len() {
+            self.cur = None;
+            return None;
+        };
+        if self.cur.is_some() {
+            self.pos += 1;
+        }
+        let c = self.data[self.pos] as char;
+        if self.cur == Some('\n') {
+            self.position.line += 1;
+            self.position.column = 0;
+        } else if self.cur.is_some() {
+            self.position.column += 1;
+        };
+        self.cur = Some(c);
+        self.cur
+    }
+
+    fn unget_char(&mut self) -> Option<char> {
+        if self.pos == 0 {
+            self.position.column = 0;
+            self.cur = None
+        } else {
+            self.pos -= 1;
+            let c = self.data[self.pos] as char;
+            if c == '\n' {
+                self.position.line -= 1;
+                let mut col_pos = self.pos;
+                while col_pos > 0 {
+                    col_pos -= 1;
+                    if self.data[col_pos] as char == '\n' {
+                        break;
+                    }
+                }
+                self.position.column = (self.pos - col_pos) as u32;
+            } else {
+                self.position.column -= 1;
+            }
+            self.cur = Some(c);
+        }
+        self.cur
+    }
+
+    fn is_space(c: char) -> bool {
+        matches!(c, ' ' | '\t' | '\r' | '\n')
+    }
+
+    fn skip_whitespace(&mut self) -> Option<char> {
+        while let Some(c) = self.cur {
+            if PrefTokenizer::is_space(c) {
+                self.get_char();
+            } else {
+                break;
+            };
+        }
+        self.cur
+    }
+
+    fn consume_escape(&mut self, token_data: &mut TokenData<'a>) -> Result<(), PrefReaderError> {
+        let pos = self.pos;
+        let escaped = self.read_escape()?;
+        if let Some(escape_char) = escaped {
+            token_data.add_slice_to_token(self.data, pos)?;
+            token_data.push_char(self, escape_char);
+        };
+        Ok(())
+    }
+
+    fn read_escape(&mut self) -> Result<Option<char>, PrefReaderError> {
+        let escape_char = match self.get_char() {
+            Some('u') => self.read_hex_escape(4, true)?,
+            Some('x') => self.read_hex_escape(2, true)?,
+            Some('\\') => '\\' as u32,
+            Some('"') => '"' as u32,
+            Some('\'') => '\'' as u32,
+            Some('r') => '\r' as u32,
+            Some('n') => '\n' as u32,
+            Some(_) => return Ok(None),
+            None => {
+                return Err(PrefReaderError::new(
+                    "EOF in character escape".into(),
+                    self.position,
+                    None,
+                ))
+            }
+        };
+        Ok(Some(char::from_u32(escape_char).ok_or_else(|| {
+            PrefReaderError::new(
+                "Invalid codepoint decoded from escape".into(),
+                self.position,
+                None,
+            )
+        })?))
+    }
+
+    fn read_hex_escape(&mut self, hex_chars: isize, first: bool) -> Result<u32, PrefReaderError> {
+        let mut value = 0;
+        for _ in 0..hex_chars {
+            match self.get_char() {
+                Some(x) => {
+                    value <<= 4;
+                    match x {
+                        '0'..='9' => value += x as u32 - '0' as u32,
+                        'a'..='f' => value += x as u32 - 'a' as u32,
+                        'A'..='F' => value += x as u32 - 'A' as u32,
+                        _ => {
+                            return Err(PrefReaderError::new(
+                                "Unexpected character in escape".into(),
+                                self.position,
+                                None,
+                            ))
+                        }
+                    }
+                }
+                None => {
+                    return Err(PrefReaderError::new(
+                        "Unexpected EOF in escape".into(),
+                        self.position,
+                        None,
+                    ))
+                }
+            }
+        }
+        if first && (0xD800..=0xDBFF).contains(&value) {
+            // First part of a surrogate pair
+            if self.get_char() != Some('\\') || self.get_char() != Some('u') {
+                return Err(PrefReaderError::new(
+                    "Lone high surrogate in surrogate pair".into(),
+                    self.position,
+                    None,
+                ));
+            }
+            self.unget_char();
+            let high_surrogate = value;
+            let low_surrogate = self.read_hex_escape(4, false)?;
+            let high_value = (high_surrogate - 0xD800) << 10;
+            let low_value = low_surrogate - 0xDC00;
+            value = high_value + low_value + 0x10000;
+        } else if first && (0xDC00..=0xDFFF).contains(&value) {
+            return Err(PrefReaderError::new(
+                "Lone low surrogate".into(),
+                self.position,
+                None,
+            ));
+        } else if !first && !(0xDC00..=0xDFFF).contains(&value) {
+            return Err(PrefReaderError::new(
+                "Invalid low surrogate in surrogate pair".into(),
+                self.position,
+                None,
+            ));
+        }
+        Ok(value)
+    }
+
+    fn get_match(&mut self, target: &str, separators: &str) -> bool {
+        let initial_pos = self.pos;
+        let mut matched = true;
+        for c in target.chars() {
+            if self.cur == Some(c) {
+                self.get_char();
+            } else {
+                matched = false;
+                break;
+            }
+        }
+
+        if !matched {
+            for _ in 0..(self.pos - initial_pos) {
+                self.unget_char();
+            }
+        } else {
+            // Check that the next character is whitespace or a separator
+            if let Some(c) = self.cur {
+                if !(PrefTokenizer::is_space(c) || separators.contains(c) || c == '/') {
+                    matched = false;
+                }
+                self.unget_char();
+            }
+            // Otherwise the token was followed by EOF. That's a valid match, but
+            // will presumably cause a parse error later.
+        }
+
+        matched
+    }
+
+    fn next_token(&mut self) -> Result<Option<TokenData<'a>>, PrefReaderError> {
+        let mut token_data = TokenData::new(TokenType::None, Position::new(), 0);
+
+        loop {
+            let mut c = match self.get_char() {
+                Some(x) => x,
+                None => return Ok(None),
+            };
+
+            self.state = match self.state {
+                TokenizerState::Junk => {
+                    c = match self.skip_whitespace() {
+                        Some(x) => x,
+                        None => return Ok(None),
+                    };
+                    match c {
+                        '/' => TokenizerState::CommentStart,
+                        '#' => {
+                            token_data.start(self, TokenType::CommentBashLine);
+                            token_data.start_pos = self.pos + 1;
+                            TokenizerState::CommentLine
+                        }
+                        _ => {
+                            self.unget_char();
+                            let next = match self.next_state {
+                                Some(x) => x,
+                                None => {
+                                    return Err(PrefReaderError::new(
+                                        "In Junk state without a next state defined".into(),
+                                        self.position,
+                                        None,
+                                    ))
+                                }
+                            };
+                            self.next_state = None;
+                            next
+                        }
+                    }
+                }
+                TokenizerState::CommentStart => match c {
+                    '*' => {
+                        token_data.start(self, TokenType::CommentBlock);
+                        token_data.start_pos = self.pos + 1;
+                        TokenizerState::CommentBlock
+                    }
+                    '/' => {
+                        token_data.start(self, TokenType::CommentLine);
+                        token_data.start_pos = self.pos + 1;
+                        TokenizerState::CommentLine
+                    }
+                    _ => {
+                        return Err(PrefReaderError::new(
+                            "Invalid character after /".into(),
+                            self.position,
+                            None,
+                        ))
+                    }
+                },
+                TokenizerState::CommentLine => match c {
+                    '\n' => {
+                        token_data.end(self.data, self.pos)?;
+                        TokenizerState::Junk
+                    }
+                    _ => TokenizerState::CommentLine,
+                },
+                TokenizerState::CommentBlock => match c {
+                    '*' => {
+                        if self.get_char() == Some('/') {
+                            token_data.end(self.data, self.pos - 1)?;
+                            TokenizerState::Junk
+                        } else {
+                            TokenizerState::CommentBlock
+                        }
+                    }
+                    _ => TokenizerState::CommentBlock,
+                },
+                TokenizerState::FunctionName => {
+                    let position = self.position;
+                    let start_pos = self.pos;
+                    match c {
+                        'u' => {
+                            if self.get_match("user_pref", "(") {
+                                token_data.start(self, TokenType::UserPrefFunction);
+                            }
+                        }
+                        's' => {
+                            if self.get_match("sticky_pref", "(") {
+                                token_data.start(self, TokenType::StickyPrefFunction);
+                            }
+                        }
+                        'p' => {
+                            if self.get_match("pref", "(") {
+                                token_data.start(self, TokenType::PrefFunction);
+                            }
+                        }
+                        _ => {}
+                    };
+                    if token_data.token_type == TokenType::None {
+                        // We didn't match anything
+                        return Err(PrefReaderError::new(
+                            "Expected a pref function name".into(),
+                            position,
+                            None,
+                        ));
+                    } else {
+                        token_data.start_pos = start_pos;
+                        token_data.position = position;
+                        token_data.end(self.data, self.pos + 1)?;
+                        self.next_state = Some(TokenizerState::AfterFunctionName);
+                        TokenizerState::Junk
+                    }
+                }
+                TokenizerState::AfterFunctionName => match c {
+                    '(' => {
+                        self.next_state = Some(TokenizerState::FunctionArgs);
+                        token_data.start(self, TokenType::Paren);
+                        token_data.end(self.data, self.pos + 1)?;
+                        self.next_state = Some(TokenizerState::FunctionArgs);
+                        TokenizerState::Junk
+                    }
+                    _ => {
+                        return Err(PrefReaderError::new(
+                            "Expected an opening paren".into(),
+                            self.position,
+                            None,
+                        ))
+                    }
+                },
+                TokenizerState::FunctionArgs => match c {
+                    ')' => {
+                        token_data.start(self, TokenType::Paren);
+                        token_data.end(self.data, self.pos + 1)?;
+                        self.next_state = Some(TokenizerState::AfterFunction);
+                        TokenizerState::Junk
+                    }
+                    _ => {
+                        self.unget_char();
+                        TokenizerState::FunctionArg
+                    }
+                },
+                TokenizerState::FunctionArg => match c {
+                    '"' => {
+                        token_data.start(self, TokenType::String);
+                        token_data.start_pos = self.pos + 1;
+                        TokenizerState::DoubleQuotedString
+                    }
+                    '\'' => {
+                        token_data.start(self, TokenType::String);
+                        token_data.start_pos = self.pos + 1;
+                        TokenizerState::SingleQuotedString
+                    }
+                    't' | 'f' => {
+                        self.unget_char();
+                        TokenizerState::Bool
+                    }
+                    '0'..='9' | '-' | '+' => {
+                        token_data.start(self, TokenType::Int);
+                        TokenizerState::Number
+                    }
+                    _ => {
+                        return Err(PrefReaderError::new(
+                            "Invalid character at start of function argument".into(),
+                            self.position,
+                            None,
+                        ))
+                    }
+                },
+                TokenizerState::DoubleQuotedString => match c {
+                    '"' => {
+                        token_data.end(self.data, self.pos)?;
+                        self.next_state = Some(TokenizerState::AfterFunctionArg);
+                        TokenizerState::Junk
+                    }
+                    '\n' => {
+                        return Err(PrefReaderError::new(
+                            "EOL in double quoted string".into(),
+                            self.position,
+                            None,
+                        ))
+                    }
+                    '\\' => {
+                        self.consume_escape(&mut token_data)?;
+                        TokenizerState::DoubleQuotedString
+                    }
+                    _ => TokenizerState::DoubleQuotedString,
+                },
+                TokenizerState::SingleQuotedString => match c {
+                    '\'' => {
+                        token_data.end(self.data, self.pos)?;
+                        self.next_state = Some(TokenizerState::AfterFunctionArg);
+                        TokenizerState::Junk
+                    }
+                    '\n' => {
+                        return Err(PrefReaderError::new(
+                            "EOL in single quoted string".into(),
+                            self.position,
+                            None,
+                        ))
+                    }
+                    '\\' => {
+                        self.consume_escape(&mut token_data)?;
+                        TokenizerState::SingleQuotedString
+                    }
+                    _ => TokenizerState::SingleQuotedString,
+                },
+                TokenizerState::Number => match c {
+                    '0'..='9' => TokenizerState::Number,
+                    ')' | ',' => {
+                        token_data.end(self.data, self.pos)?;
+                        self.unget_char();
+                        self.next_state = Some(TokenizerState::AfterFunctionArg);
+                        TokenizerState::Junk
+                    }
+                    x if PrefTokenizer::is_space(x) => {
+                        token_data.end(self.data, self.pos)?;
+                        self.next_state = Some(TokenizerState::AfterFunctionArg);
+                        TokenizerState::Junk
+                    }
+                    _ => {
+                        return Err(PrefReaderError::new(
+                            "Invalid character in number literal".into(),
+                            self.position,
+                            None,
+                        ))
+                    }
+                },
+                TokenizerState::Bool => {
+                    let start_pos = self.pos;
+                    let position = self.position;
+                    match c {
+                        't' => {
+                            if self.get_match("true", ",)") {
+                                token_data.start(self, TokenType::Bool)
+                            }
+                        }
+                        'f' => {
+                            if self.get_match("false", ",)") {
+                                token_data.start(self, TokenType::Bool)
+                            }
+                        }
+                        _ => {}
+                    };
+                    if token_data.token_type == TokenType::None {
+                        return Err(PrefReaderError::new(
+                            "Unexpected characters in function argument".into(),
+                            position,
+                            None,
+                        ));
+                    } else {
+                        token_data.start_pos = start_pos;
+                        token_data.position = position;
+                        token_data.end(self.data, self.pos + 1)?;
+                        self.next_state = Some(TokenizerState::AfterFunctionArg);
+                        TokenizerState::Junk
+                    }
+                }
+                TokenizerState::AfterFunctionArg => match c {
+                    ',' => {
+                        token_data.start(self, TokenType::Comma);
+                        token_data.end(self.data, self.pos + 1)?;
+                        self.next_state = Some(TokenizerState::FunctionArg);
+                        TokenizerState::Junk
+                    }
+                    ')' => {
+                        token_data.start(self, TokenType::Paren);
+                        token_data.end(self.data, self.pos + 1)?;
+                        self.next_state = Some(TokenizerState::AfterFunction);
+                        TokenizerState::Junk
+                    }
+                    _ => {
+                        return Err(PrefReaderError::new(
+                            "Unexpected character after function argument".into(),
+                            self.position,
+                            None,
+                        ))
+                    }
+                },
+                TokenizerState::AfterFunction => match c {
+                    ';' => {
+                        token_data.start(self, TokenType::Semicolon);
+                        token_data.end(self.data, self.pos)?;
+                        self.next_state = Some(TokenizerState::FunctionName);
+                        TokenizerState::Junk
+                    }
+                    _ => {
+                        return Err(PrefReaderError::new(
+                            "Unexpected character after function".into(),
+                            self.position,
+                            None,
+                        ))
+                    }
+                },
+                TokenizerState::Error => TokenizerState::Error,
+            };
+            if token_data.complete {
+                return Ok(Some(token_data));
+            }
+        }
+    }
+}
+
+impl<'a> Iterator for PrefTokenizer<'a> {
+    type Item = PrefToken<'a>;
+
+    fn next(&mut self) -> Option<PrefToken<'a>> {
+        if let TokenizerState::Error = self.state {
+            return None;
+        }
+        let token_data = match self.next_token() {
+            Err(e) => {
+                self.state = TokenizerState::Error;
+                return Some(PrefToken::Error(e.message.clone(), e.position));
+            }
+            Ok(Some(token_data)) => token_data,
+            Ok(None) => return None,
+        };
+        let token = self.make_token(token_data);
+        Some(token)
+    }
+}
+
+pub fn tokenize(data: &[u8]) -> PrefTokenizer {
+    PrefTokenizer::new(data)
+}
+
+pub fn serialize_token<T: Write>(token: &PrefToken, output: &mut T) -> Result<(), PrefReaderError> {
+    let mut data_buf = String::new();
+
+    let data = match *token {
+        PrefToken::PrefFunction(_) => "pref",
+        PrefToken::UserPrefFunction(_) => "user_pref",
+        PrefToken::StickyPrefFunction(_) => "sticky_pref",
+        PrefToken::CommentBlock(ref data, _) => {
+            data_buf.reserve(data.len() + 4);
+            data_buf.push_str("/*");
+            data_buf.push_str(data.borrow());
+            data_buf.push('*');
+            &*data_buf
+        }
+        PrefToken::CommentLine(ref data, _) => {
+            data_buf.reserve(data.len() + 2);
+            data_buf.push_str("//");
+            data_buf.push_str(data.borrow());
+            &*data_buf
+        }
+        PrefToken::CommentBashLine(ref data, _) => {
+            data_buf.reserve(data.len() + 1);
+            data_buf.push('#');
+            data_buf.push_str(data.borrow());
+            &*data_buf
+        }
+        PrefToken::Paren(data, _) => {
+            data_buf.push(data);
+            &*data_buf
+        }
+        PrefToken::Comma(_) => ",",
+        PrefToken::Semicolon(_) => ";\n",
+        PrefToken::String(ref data, _) => {
+            data_buf.reserve(data.len() + 2);
+            data_buf.push('"');
+            data_buf.push_str(escape_quote(data.borrow()).borrow());
+            data_buf.push('"');
+            &*data_buf
+        }
+        PrefToken::Int(data, _) => {
+            data_buf.push_str(&data.to_string());
+            &*data_buf
+        }
+        PrefToken::Bool(data, _) => {
+            if data {
+                "true"
+            } else {
+                "false"
+            }
+        }
+        PrefToken::Error(ref data, pos) => {
+            return Err(PrefReaderError::new(data.clone(), pos, None))
+        }
+    };
+    output.write_all(data.as_bytes())?;
+    Ok(())
+}
+
+pub fn serialize_tokens<'a, I, W>(tokens: I, output: &mut W) -> Result<(), PrefReaderError>
+where
+    I: Iterator<Item = &'a PrefToken<'a>>,
+    W: Write,
+{
+    for token in tokens {
+        serialize_token(token, output)?;
+    }
+    Ok(())
+}
+
+fn escape_quote(data: &str) -> Cow<str> {
+    // Not very efficient…
+    if data.contains('"') || data.contains('\\') {
+        Cow::Owned(data.replace('\\', r#"\\"#).replace('"', r#"\""#))
+    } else {
+        Cow::Borrowed(data)
+    }
+}
+
+#[derive(Debug, PartialEq)]
+enum ParserState {
+    Function,
+    Key,
+    Value,
+}
+
+struct PrefBuilder {
+    key: Option<String>,
+    value: Option<PrefValue>,
+    sticky: bool,
+}
+
+impl PrefBuilder {
+    fn new() -> PrefBuilder {
+        PrefBuilder {
+            key: None,
+            value: None,
+            sticky: false,
+        }
+    }
+}
+
+fn skip_comments<'a>(tokenizer: &mut PrefTokenizer<'a>) -> Option<PrefToken<'a>> {
+    loop {
+        match tokenizer.next() {
+            Some(PrefToken::CommentBashLine(_, _))
+            | Some(PrefToken::CommentBlock(_, _))
+            | Some(PrefToken::CommentLine(_, _)) => {}
+            Some(x) => return Some(x),
+            None => return None,
+        }
+    }
+}
+
+pub fn parse_tokens(tokenizer: &mut PrefTokenizer<'_>) -> Result<Preferences, PrefReaderError> {
+    let mut state = ParserState::Function;
+    let mut current_pref = PrefBuilder::new();
+    let mut rv = Preferences::new();
+
+    loop {
+        // Not just using a for loop here seems strange, but this restricts the
+        // scope of the borrow
+        let token = {
+            match tokenizer.next() {
+                Some(x) => x,
+                None => break,
+            }
+        };
+        // First deal with comments and errors
+        match token {
+            PrefToken::Error(msg, position) => {
+                return Err(PrefReaderError::new(msg, position, None));
+            }
+            PrefToken::CommentBashLine(_, _)
+            | PrefToken::CommentLine(_, _)
+            | PrefToken::CommentBlock(_, _) => continue,
+            _ => {}
+        }
+        state = match state {
+            ParserState::Function => {
+                match token {
+                    PrefToken::PrefFunction(_) => {
+                        current_pref.sticky = false;
+                    }
+                    PrefToken::UserPrefFunction(_) => {
+                        current_pref.sticky = false;
+                    }
+                    PrefToken::StickyPrefFunction(_) => {
+                        current_pref.sticky = true;
+                    }
+                    _ => {
+                        return Err(PrefReaderError::new(
+                            "Expected pref function".into(),
+                            token.position(),
+                            None,
+                        ));
+                    }
+                }
+                let next = skip_comments(tokenizer);
+                match next {
+                    Some(PrefToken::Paren('(', _)) => ParserState::Key,
+                    _ => {
+                        return Err(PrefReaderError::new(
+                            "Expected open paren".into(),
+                            next.map(|x| x.position()).unwrap_or(tokenizer.position),
+                            None,
+                        ))
+                    }
+                }
+            }
+            ParserState::Key => {
+                match token {
+                    PrefToken::String(data, _) => current_pref.key = Some(data.into_owned()),
+                    _ => {
+                        return Err(PrefReaderError::new(
+                            "Expected string".into(),
+                            token.position(),
+                            None,
+                        ));
+                    }
+                }
+                let next = skip_comments(tokenizer);
+                match next {
+                    Some(PrefToken::Comma(_)) => ParserState::Value,
+                    _ => {
+                        return Err(PrefReaderError::new(
+                            "Expected comma".into(),
+                            next.map(|x| x.position()).unwrap_or(tokenizer.position),
+                            None,
+                        ))
+                    }
+                }
+            }
+            ParserState::Value => {
+                match token {
+                    PrefToken::String(data, _) => {
+                        current_pref.value = Some(PrefValue::String(data.into_owned()))
+                    }
+                    PrefToken::Int(data, _) => current_pref.value = Some(PrefValue::Int(data)),
+                    PrefToken::Bool(data, _) => current_pref.value = Some(PrefValue::Bool(data)),
+                    _ => {
+                        return Err(PrefReaderError::new(
+                            "Expected value".into(),
+                            token.position(),
+                            None,
+                        ))
+                    }
+                }
+                let next = skip_comments(tokenizer);
+                match next {
+                    Some(PrefToken::Paren(')', _)) => {}
+                    _ => {
+                        return Err(PrefReaderError::new(
+                            "Expected close paren".into(),
+                            next.map(|x| x.position()).unwrap_or(tokenizer.position),
+                            None,
+                        ))
+                    }
+                }
+                let next = skip_comments(tokenizer);
+                match next {
+                    Some(PrefToken::Semicolon(_)) | None => {}
+                    _ => {
+                        return Err(PrefReaderError::new(
+                            "Expected semicolon".into(),
+                            next.map(|x| x.position()).unwrap_or(tokenizer.position),
+                            None,
+                        ))
+                    }
+                }
+                let key = mem::replace(&mut current_pref.key, None);
+                let value = mem::replace(&mut current_pref.value, None);
+                let pref = if current_pref.sticky {
+                    Pref::new_sticky(value.unwrap())
+                } else {
+                    Pref::new(value.unwrap())
+                };
+                rv.insert(key.unwrap(), pref);
+                current_pref.sticky = false;
+                ParserState::Function
+            }
+        }
+    }
+    match state {
+        ParserState::Key | ParserState::Value => {
+            return Err(PrefReaderError::new(
+                "EOF in middle of function".into(),
+                tokenizer.position,
+                None,
+            ));
+        }
+        _ => {}
+    }
+    Ok(rv)
+}
+
+pub fn serialize<W: Write>(prefs: &Preferences, output: &mut W) -> io::Result<()> {
+    let mut p: Vec<_> = prefs.iter().collect();
+    p.sort_by(|a, b| a.0.cmp(b.0));
+    for &(key, pref) in &p {
+        let func = if pref.sticky {
+            "sticky_pref("
+        } else {
+            "user_pref("
+        }
+        .as_bytes();
+        output.write_all(func)?;
+        output.write_all(b"\"")?;
+        output.write_all(escape_quote(key).as_bytes())?;
+        output.write_all(b"\"")?;
+        output.write_all(b", ")?;
+        match pref.value {
+            PrefValue::Bool(x) => {
+                output.write_all(if x { b"true" } else { b"false" })?;
+            }
+            PrefValue::Int(x) => {
+                output.write_all(x.to_string().as_bytes())?;
+            }
+            PrefValue::String(ref x) => {
+                output.write_all(b"\"")?;
+                output.write_all(escape_quote(x).as_bytes())?;
+                output.write_all(b"\"")?;
+            }
+        };
+        output.write_all(b");\n")?;
+    }
+    Ok(())
+}
+
+pub fn parse(data: &[u8]) -> Result<Preferences, PrefReaderError> {
+    let mut tokenizer = tokenize(data);
+    parse_tokens(&mut tokenizer)
+}
diff --git a/testing/mozbase/rust/mozprofile/src/profile.rs b/testing/mozbase/rust/mozprofile/src/profile.rs
new file mode 100644
index 0000000000..f4037adfa9
--- /dev/null
+++ b/testing/mozbase/rust/mozprofile/src/profile.rs
@@ -0,0 +1,135 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+use crate::preferences::{Pref, Preferences};
+use crate::prefreader::{parse, serialize, PrefReaderError};
+use std::collections::btree_map::Iter;
+use std::fs::File;
+use std::io::prelude::*;
+use std::io::Result as IoResult;
+use std::path::{Path, PathBuf};
+use tempfile::{Builder, TempDir};
+
+#[derive(Debug)]
+pub struct Profile {
+    pub path: PathBuf,
+    pub temp_dir: Option<TempDir>,
+    prefs: Option<PrefFile>,
+    user_prefs: Option<PrefFile>,
+}
+
+impl PartialEq for Profile {
+    fn eq(&self, other: &Profile) -> bool {
+        self.path == other.path
+    }
+}
+
+impl Profile {
+    pub fn new(temp_root: Option<&Path>) -> IoResult<Profile> {
+        let mut dir_builder = Builder::new();
+        dir_builder.prefix("rust_mozprofile");
+        let dir = if let Some(temp_root) = temp_root {
+            dir_builder.tempdir_in(temp_root)
+        } else {
+            dir_builder.tempdir()
+        }?;
+        let path = dir.path().to_path_buf();
+        let temp_dir = Some(dir);
+        Ok(Profile {
+            path,
+            temp_dir,
+            prefs: None,
+            user_prefs: None,
+        })
+    }
+
+    pub fn new_from_path(p: &Path) -> IoResult<Profile> {
+        let path = p.to_path_buf();
+        let temp_dir = None;
+        Ok(Profile {
+            path,
+            temp_dir,
+            prefs: None,
+            user_prefs: None,
+        })
+    }
+
+    pub fn prefs(&mut self) -> Result<&mut PrefFile, PrefReaderError> {
+        if self.prefs.is_none() {
+            let mut pref_path = PathBuf::from(&self.path);
+            pref_path.push("prefs.js");
+            self.prefs = Some(PrefFile::new(pref_path)?)
+        };
+        // This error handling doesn't make much sense
+        Ok(self.prefs.as_mut().unwrap())
+    }
+
+    pub fn user_prefs(&mut self) -> Result<&mut PrefFile, PrefReaderError> {
+        if self.user_prefs.is_none() {
+            let mut pref_path = PathBuf::from(&self.path);
+            pref_path.push("user.js");
+            self.user_prefs = Some(PrefFile::new(pref_path)?)
+        };
+        // This error handling doesn't make much sense
+        Ok(self.user_prefs.as_mut().unwrap())
+    }
+}
+
+#[derive(Debug)]
+pub struct PrefFile {
+    pub path: PathBuf,
+    pub prefs: Preferences,
+}
+
+impl PrefFile {
+    pub fn new(path: PathBuf) -> Result<PrefFile, PrefReaderError> {
+        let prefs = if !path.exists() {
+            Preferences::new()
+        } else {
+            let mut f = File::open(&path)?;
+            let mut buf = String::with_capacity(4096);
+            f.read_to_string(&mut buf)?;
+            parse(buf.as_bytes())?
+        };
+
+        Ok(PrefFile { path, prefs })
+    }
+
+    pub fn write(&self) -> IoResult<()> {
+        let mut f = File::create(&self.path)?;
+        serialize(&self.prefs, &mut f)
+    }
+
+    pub fn insert_slice<K>(&mut self, preferences: &[(K, Pref)])
+    where
+        K: Into<String> + Clone,
+    {
+        for &(ref name, ref value) in preferences.iter() {
+            self.insert((*name).clone(), (*value).clone());
+        }
+    }
+
+    pub fn insert<K>(&mut self, key: K, value: Pref)
+    where
+        K: Into<String>,
+    {
+        self.prefs.insert(key.into(), value);
+    }
+
+    pub fn remove(&mut self, key: &str) -> Option<Pref> {
+        self.prefs.remove(key)
+    }
+
+    pub fn get(&mut self, key: &str) -> Option<&Pref> {
+        self.prefs.get(key)
+    }
+
+    pub fn contains_key(&self, key: &str) -> bool {
+        self.prefs.contains_key(key)
+    }
+
+    pub fn iter(&self) -> Iter<String, Pref> {
+        self.prefs.iter()
+    }
+}
diff --git a/testing/mozbase/rust/mozrunner/Cargo.toml b/testing/mozbase/rust/mozrunner/Cargo.toml
new file mode 100644
index 0000000000..6cd682a06c
--- /dev/null
+++ b/testing/mozbase/rust/mozrunner/Cargo.toml
@@ -0,0 +1,27 @@
+[package]
+edition = "2018"
+name = "mozrunner"
+version = "0.15.0"
+authors = ["Mozilla"]
+description = "Reliable Firefox process management."
+keywords = [
+    "firefox",
+    "mozilla",
+    "process-manager",
+]
+license = "MPL-2.0"
+repository = "https://hg.mozilla.org/mozilla-central/file/tip/testing/mozbase/rust/mozrunner"
+
+[dependencies]
+log = "0.4"
+mozprofile = { path = "../mozprofile", version = "0.9" }
+plist = "1.0"
+
+[target.'cfg(target_os = "windows")'.dependencies]
+winreg = "0.10.1"
+
+[target.'cfg(target_os = "macos")'.dependencies]
+dirs = "4"
+
+[[bin]]
+name = "firefox-default-path"
diff --git a/testing/mozbase/rust/mozrunner/src/bin/firefox-default-path.rs b/testing/mozbase/rust/mozrunner/src/bin/firefox-default-path.rs
new file mode 100644
index 0000000000..94958aac90
--- /dev/null
+++ b/testing/mozbase/rust/mozrunner/src/bin/firefox-default-path.rs
@@ -0,0 +1,21 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+extern crate mozrunner;
+
+use mozrunner::runner::platform;
+use std::io::Write;
+
+fn main() {
+    let (path, code) = platform::firefox_default_path()
+        .map(|x| (x.to_string_lossy().into_owned(), 0))
+        .unwrap_or(("Firefox binary not found".to_owned(), 1));
+
+    let mut writer: Box<dyn Write> = match code {
+        0 => Box::new(std::io::stdout()),
+        _ => Box::new(std::io::stderr()),
+    };
+    writeln!(&mut writer, "{}", &*path).unwrap();
+    std::process::exit(code);
+}
diff --git a/testing/mozbase/rust/mozrunner/src/firefox_args.rs b/testing/mozbase/rust/mozrunner/src/firefox_args.rs
new file mode 100644
index 0000000000..49f873f9dc
--- /dev/null
+++ b/testing/mozbase/rust/mozrunner/src/firefox_args.rs
@@ -0,0 +1,384 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+//! Argument string parsing and matching functions for Firefox.
+//!
+//! Which arguments Firefox accepts and in what style depends on the platform.
+//! On Windows only, arguments can be prefixed with `/` (slash), such as
+//! `/screenshot`.  Elsewhere, including Windows, arguments may be prefixed
+//! with both single (`-screenshot`) and double (`--screenshot`) dashes.
+//!
+//! An argument's name is determined by a space or an assignment operator (`=`)
+//! so that for the string `-foo=bar`, `foo` is considered the argument's
+//! basename.
+
+use crate::runner::platform;
+use std::ffi::{OsStr, OsString};
+use std::fmt;
+
+/// Parse an argument string into a name and value
+///
+/// Given an argument like `"--arg=value"` this will split it into
+/// `(Some("arg"), Some("value")). For a case like `"--arg"` it will
+/// return `(Some("arg"), None)` and where the input doesn't look like
+/// an argument e.g. `"value"` it will return `(None, Some("value"))`
+fn parse_arg_name_value<T>(arg: T) -> (Option<String>, Option<String>)
+where
+    T: AsRef<OsStr>,
+{
+    let arg_os_str: &OsStr = arg.as_ref();
+    let arg_str = arg_os_str.to_string_lossy();
+
+    let mut name_start = 0;
+    let mut name_end = 0;
+
+    // Look for an argument name at the start of the
+    // string
+    for (i, c) in arg_str.chars().enumerate() {
+        if i == 0 {
+            if !platform::arg_prefix_char(c) {
+                break;
+            }
+        } else if i == 1 {
+            if name_end_char(c) {
+                break;
+            } else if c != '-' {
+                name_start = i;
+                name_end = name_start + 1;
+            } else {
+                name_start = i + 1;
+                name_end = name_start;
+            }
+        } else {
+            name_end += 1;
+            if name_end_char(c) {
+                name_end -= 1;
+                break;
+            }
+        }
+    }
+
+    let name = if name_start > 0 && name_end > name_start {
+        Some(arg_str[name_start..name_end].into())
+    } else {
+        None
+    };
+
+    // If there are characters in the string after the argument, read
+    // them as the value, excluding the seperator (e.g. "=") if
+    // present.
+    let mut value_start = name_end;
+    let value_end = arg_str.len();
+    let value = if value_start < value_end {
+        if let Some(c) = arg_str[value_start..value_end].chars().next() {
+            if name_end_char(c) {
+                value_start += 1;
+            }
+        }
+        Some(arg_str[value_start..value_end].into())
+    } else {
+        None
+    };
+    (name, value)
+}
+
+fn name_end_char(c: char) -> bool {
+    c == ' ' || c == '='
+}
+
+/// Represents a Firefox command-line argument.
+#[derive(Debug, PartialEq)]
+pub enum Arg {
+    /// `-foreground` ensures application window gets focus, which is not the
+    /// default on macOS. As such Firefox only supports it on MacOS.
+    Foreground,
+
+    /// --marionette enables Marionette in the application which is used
+    /// by WebDriver HTTP.
+    Marionette,
+
+    /// `-no-remote` prevents remote commands to this instance of Firefox, and
+    /// ensure we always start a new instance.
+    NoRemote,
+
+    /// `-P NAME` starts Firefox with a profile with a given name.
+    NamedProfile,
+
+    /// `-profile PATH` starts Firefox with the profile at the specified path.
+    Profile,
+
+    /// `-ProfileManager` starts Firefox with the profile chooser dialogue.
+    ProfileManager,
+
+    /// All other arguments.
+    Other(String),
+
+    /// --remote-allow-hosts contains comma-separated values of the Host header
+    /// to allow for incoming WebSocket requests of the Remote Agent.
+    RemoteAllowHosts,
+
+    /// --remote-allow-origins contains comma-separated values of the Origin header
+    /// to allow for incoming WebSocket requests of the Remote Agent.
+    RemoteAllowOrigins,
+
+    /// --remote-debugging-port enables the Remote Agent in the application
+    /// which is used for the WebDriver BiDi and CDP remote debugging protocols.
+    RemoteDebuggingPort,
+
+    /// Not an argument.
+    None,
+}
+
+impl Arg {
+    pub fn new(name: &str) -> Arg {
+        match name {
+            "foreground" => Arg::Foreground,
+            "marionette" => Arg::Marionette,
+            "no-remote" => Arg::NoRemote,
+            "profile" => Arg::Profile,
+            "P" => Arg::NamedProfile,
+            "ProfileManager" => Arg::ProfileManager,
+            "remote-allow-hosts" => Arg::RemoteAllowHosts,
+            "remote-allow-origins" => Arg::RemoteAllowOrigins,
+            "remote-debugging-port" => Arg::RemoteDebuggingPort,
+            _ => Arg::Other(name.into()),
+        }
+    }
+}
+
+impl<'a> From<&'a OsString> for Arg {
+    fn from(arg_str: &OsString) -> Arg {
+        if let (Some(name), _) = parse_arg_name_value(arg_str) {
+            Arg::new(&name)
+        } else {
+            Arg::None
+        }
+    }
+}
+
+impl fmt::Display for Arg {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.write_str(&match self {
+            Arg::Foreground => "--foreground".to_string(),
+            Arg::Marionette => "--marionette".to_string(),
+            Arg::NamedProfile => "-P".to_string(),
+            Arg::None => "".to_string(),
+            Arg::NoRemote => "--no-remote".to_string(),
+            Arg::Other(x) => format!("--{}", x),
+            Arg::Profile => "--profile".to_string(),
+            Arg::ProfileManager => "--ProfileManager".to_string(),
+            Arg::RemoteAllowHosts => "--remote-allow-hosts".to_string(),
+            Arg::RemoteAllowOrigins => "--remote-allow-origins".to_string(),
+            Arg::RemoteDebuggingPort => "--remote-debugging-port".to_string(),
+        })
+    }
+}
+
+/// Parse an iterator over arguments into an vector of (name, value)
+/// tuples
+///
+/// Each entry in the input argument will produce a single item in the
+/// output. Because we don't know anything about the specific
+/// arguments, something that doesn't parse as a named argument may
+/// either be the value of a previous named argument, or may be a
+/// positional argument.
+pub fn parse_args<'a>(
+    args: impl Iterator<Item = &'a OsString>,
+) -> Vec<(Option<Arg>, Option<String>)> {
+    args.map(parse_arg_name_value)
+        .map(|(name, value)| {
+            if let Some(arg_name) = name {
+                (Some(Arg::new(&arg_name)), value)
+            } else {
+                (None, value)
+            }
+        })
+        .collect()
+}
+
+/// Given an iterator over all arguments, get the value of an argument
+///
+/// This assumes that the argument takes a single value and that is
+/// either provided as a single argument entry
+/// (e.g. `["--name=value"]`) or as the following argument
+/// (e.g. `["--name", "value"])
+pub fn get_arg_value<'a>(
+    mut parsed_args: impl Iterator<Item = &'a (Option<Arg>, Option<String>)>,
+    arg: Arg,
+) -> Option<String> {
+    let mut found_value = None;
+    for (arg_name, arg_value) in &mut parsed_args {
+        if let (Some(name), value) = (arg_name, arg_value) {
+            if *name == arg {
+                found_value = value.clone();
+                break;
+            }
+        }
+    }
+    if found_value.is_none() {
+        // If there wasn't a value, check if the following argument is a value
+        if let Some((None, value)) = parsed_args.next() {
+            found_value = value.clone();
+        }
+    }
+    found_value
+}
+
+#[cfg(test)]
+mod tests {
+    use super::{get_arg_value, parse_arg_name_value, parse_args, Arg};
+    use std::ffi::OsString;
+
+    fn parse(arg: &str, name: Option<&str>) {
+        let (result, _) = parse_arg_name_value(arg);
+        assert_eq!(result, name.map(|x| x.to_string()));
+    }
+
+    #[test]
+    fn test_parse_arg_name_value() {
+        parse("-p", Some("p"));
+        parse("--p", Some("p"));
+        parse("--profile foo", Some("profile"));
+        parse("--profile", Some("profile"));
+        parse("--", None);
+        parse("", None);
+        parse("-=", None);
+        parse("--=", None);
+        parse("-- foo", None);
+        parse("foo", None);
+        parse("/ foo", None);
+        parse("/- foo", None);
+        parse("/=foo", None);
+        parse("foo", None);
+        parse("-profile", Some("profile"));
+        parse("-profile=foo", Some("profile"));
+        parse("-profile = foo", Some("profile"));
+        parse("-profile abc", Some("profile"));
+        parse("-profile /foo", Some("profile"));
+    }
+
+    #[cfg(target_os = "windows")]
+    #[test]
+    fn test_parse_arg_name_value_windows() {
+        parse("/profile", Some("profile"));
+    }
+
+    #[cfg(not(target_os = "windows"))]
+    #[test]
+    fn test_parse_arg_name_value_non_windows() {
+        parse("/profile", None);
+    }
+
+    #[test]
+    fn test_arg_from_osstring() {
+        assert_eq!(Arg::from(&OsString::from("--foreground")), Arg::Foreground);
+        assert_eq!(Arg::from(&OsString::from("-foreground")), Arg::Foreground);
+
+        assert_eq!(Arg::from(&OsString::from("--marionette")), Arg::Marionette);
+        assert_eq!(Arg::from(&OsString::from("-marionette")), Arg::Marionette);
+
+        assert_eq!(Arg::from(&OsString::from("--no-remote")), Arg::NoRemote);
+        assert_eq!(Arg::from(&OsString::from("-no-remote")), Arg::NoRemote);
+
+        assert_eq!(Arg::from(&OsString::from("-- profile")), Arg::None);
+        assert_eq!(Arg::from(&OsString::from("profile")), Arg::None);
+        assert_eq!(Arg::from(&OsString::from("profile -P")), Arg::None);
+        assert_eq!(
+            Arg::from(&OsString::from("-profiled")),
+            Arg::Other("profiled".into())
+        );
+        assert_eq!(
+            Arg::from(&OsString::from("-PROFILEMANAGER")),
+            Arg::Other("PROFILEMANAGER".into())
+        );
+
+        assert_eq!(Arg::from(&OsString::from("--profile")), Arg::Profile);
+        assert_eq!(Arg::from(&OsString::from("-profile foo")), Arg::Profile);
+
+        assert_eq!(
+            Arg::from(&OsString::from("--ProfileManager")),
+            Arg::ProfileManager
+        );
+        assert_eq!(
+            Arg::from(&OsString::from("-ProfileManager")),
+            Arg::ProfileManager
+        );
+
+        // TODO: -Ptest is valid
+        //assert_eq!(Arg::from(&OsString::from("-Ptest")), Arg::NamedProfile);
+        assert_eq!(Arg::from(&OsString::from("-P")), Arg::NamedProfile);
+        assert_eq!(Arg::from(&OsString::from("-P test")), Arg::NamedProfile);
+
+        assert_eq!(
+            Arg::from(&OsString::from("--remote-debugging-port")),
+            Arg::RemoteDebuggingPort
+        );
+        assert_eq!(
+            Arg::from(&OsString::from("-remote-debugging-port")),
+            Arg::RemoteDebuggingPort
+        );
+        assert_eq!(
+            Arg::from(&OsString::from("--remote-debugging-port 9222")),
+            Arg::RemoteDebuggingPort
+        );
+
+        assert_eq!(
+            Arg::from(&OsString::from("--remote-allow-hosts")),
+            Arg::RemoteAllowHosts
+        );
+        assert_eq!(
+            Arg::from(&OsString::from("-remote-allow-hosts")),
+            Arg::RemoteAllowHosts
+        );
+        assert_eq!(
+            Arg::from(&OsString::from("--remote-allow-hosts 9222")),
+            Arg::RemoteAllowHosts
+        );
+
+        assert_eq!(
+            Arg::from(&OsString::from("--remote-allow-origins")),
+            Arg::RemoteAllowOrigins
+        );
+        assert_eq!(
+            Arg::from(&OsString::from("-remote-allow-origins")),
+            Arg::RemoteAllowOrigins
+        );
+        assert_eq!(
+            Arg::from(&OsString::from("--remote-allow-origins http://foo")),
+            Arg::RemoteAllowOrigins
+        );
+    }
+
+    #[test]
+    fn test_get_arg_value() {
+        let args = vec!["-P", "ProfileName", "--profile=/path/", "--no-remote"]
+            .iter()
+            .map(|x| OsString::from(x))
+            .collect::<Vec<OsString>>();
+        let parsed_args = parse_args(args.iter());
+        assert_eq!(
+            get_arg_value(parsed_args.iter(), Arg::NamedProfile),
+            Some("ProfileName".into())
+        );
+        assert_eq!(
+            get_arg_value(parsed_args.iter(), Arg::Profile),
+            Some("/path/".into())
+        );
+        assert_eq!(get_arg_value(parsed_args.iter(), Arg::NoRemote), None);
+
+        let args = vec!["--profile=", "-P test"]
+            .iter()
+            .map(|x| OsString::from(x))
+            .collect::<Vec<OsString>>();
+        let parsed_args = parse_args(args.iter());
+        assert_eq!(
+            get_arg_value(parsed_args.iter(), Arg::NamedProfile),
+            Some("test".into())
+        );
+        assert_eq!(
+            get_arg_value(parsed_args.iter(), Arg::Profile),
+            Some("".into())
+        );
+    }
+}
diff --git a/testing/mozbase/rust/mozrunner/src/lib.rs b/testing/mozbase/rust/mozrunner/src/lib.rs
new file mode 100644
index 0000000000..5634de11bf
--- /dev/null
+++ b/testing/mozbase/rust/mozrunner/src/lib.rs
@@ -0,0 +1,20 @@
+#![forbid(unsafe_code)]
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#[macro_use]
+extern crate log;
+#[cfg(target_os = "macos")]
+extern crate dirs;
+extern crate mozprofile;
+#[cfg(target_os = "macos")]
+extern crate plist;
+#[cfg(target_os = "windows")]
+extern crate winreg;
+
+pub mod firefox_args;
+pub mod path;
+pub mod runner;
+
+pub use crate::runner::platform::firefox_default_path;
diff --git a/testing/mozbase/rust/mozrunner/src/path.rs b/testing/mozbase/rust/mozrunner/src/path.rs
new file mode 100644
index 0000000000..0bf1eda9ed
--- /dev/null
+++ b/testing/mozbase/rust/mozrunner/src/path.rs
@@ -0,0 +1,48 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+//! Provides utilities for searching the system path.
+
+use std::env;
+use std::path::{Path, PathBuf};
+
+#[cfg(unix)]
+fn is_executable(path: &Path) -> bool {
+    use std::fs;
+    use std::os::unix::fs::PermissionsExt;
+
+    // Permissions are a set of four 4-bit bitflags, represented by a single octal
+    // digit.  The lowest bit of each of the last three values represents the
+    // executable permission for all, group and user, repsectively.  We assume the
+    // file is executable if any of these are set.
+    match fs::metadata(path).ok() {
+        Some(meta) => meta.permissions().mode() & 0o111 != 0,
+        None => false,
+    }
+}
+
+#[cfg(not(unix))]
+fn is_executable(_: &Path) -> bool {
+    true
+}
+
+/// Determines if the path is an executable binary.  That is, if it exists, is
+/// a file, and is executable where applicable.
+pub fn is_binary(path: &Path) -> bool {
+    path.exists() && path.is_file() && is_executable(path)
+}
+
+/// Searches the system path (`PATH`) for an executable binary and returns the
+/// first match, or `None` if not found.
+pub fn find_binary(binary_name: &str) -> Option<PathBuf> {
+    env::var_os("PATH").and_then(|path_env| {
+        for mut path in env::split_paths(&path_env) {
+            path.push(binary_name);
+            if is_binary(&path) {
+                return Some(path);
+            }
+        }
+        None
+    })
+}
diff --git a/testing/mozbase/rust/mozrunner/src/runner.rs b/testing/mozbase/rust/mozrunner/src/runner.rs
new file mode 100644
index 0000000000..b3deafe27b
--- /dev/null
+++ b/testing/mozbase/rust/mozrunner/src/runner.rs
@@ -0,0 +1,570 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+use mozprofile::prefreader::PrefReaderError;
+use mozprofile::profile::Profile;
+use std::collections::HashMap;
+use std::convert::From;
+use std::error::Error;
+use std::ffi::{OsStr, OsString};
+use std::fmt;
+use std::io;
+use std::io::ErrorKind;
+use std::path::{Path, PathBuf};
+use std::process;
+use std::process::{Child, Command, Stdio};
+use std::thread;
+use std::time;
+
+use crate::firefox_args::Arg;
+
+pub trait Runner {
+    type Process;
+
+    fn arg<S>(&mut self, arg: S) -> &mut Self
+    where
+        S: AsRef<OsStr>;
+
+    fn args<I, S>(&mut self, args: I) -> &mut Self
+    where
+        I: IntoIterator<Item = S>,
+        S: AsRef<OsStr>;
+
+    fn env<K, V>(&mut self, key: K, value: V) -> &mut Self
+    where
+        K: AsRef<OsStr>,
+        V: AsRef<OsStr>;
+
+    fn envs<I, K, V>(&mut self, envs: I) -> &mut Self
+    where
+        I: IntoIterator<Item = (K, V)>,
+        K: AsRef<OsStr>,
+        V: AsRef<OsStr>;
+
+    fn stdout<T>(&mut self, stdout: T) -> &mut Self
+    where
+        T: Into<Stdio>;
+
+    fn stderr<T>(&mut self, stderr: T) -> &mut Self
+    where
+        T: Into<Stdio>;
+
+    fn start(self) -> Result<Self::Process, RunnerError>;
+}
+
+pub trait RunnerProcess {
+    /// Attempts to collect the exit status of the process if it has already exited.
+    ///
+    /// This function will not block the calling thread and will only advisorily check to see if
+    /// the child process has exited or not.  If the process has exited then on Unix the process ID
+    /// is reaped.  This function is guaranteed to repeatedly return a successful exit status so
+    /// long as the child has already exited.
+    ///
+    /// If the process has exited, then `Ok(Some(status))` is returned.  If the exit status is not
+    /// available at this time then `Ok(None)` is returned.  If an error occurs, then that error is
+    /// returned.
+    fn try_wait(&mut self) -> io::Result<Option<process::ExitStatus>>;
+
+    /// Waits for the process to exit completely, killing it if it does not stop within `timeout`,
+    /// and returns the status that it exited with.
+    ///
+    /// Firefox' integrated background monitor observes long running threads during shutdown and
+    /// kills these after 63 seconds.  If the process fails to exit within the duration of
+    /// `timeout`, it is forcefully killed.
+    ///
+    /// This function will continue to have the same return value after it has been called at least
+    /// once.
+    fn wait(&mut self, timeout: time::Duration) -> io::Result<process::ExitStatus>;
+
+    /// Determine if the process is still running.
+    fn running(&mut self) -> bool;
+
+    /// Forces the process to exit and returns the exit status.  This is
+    /// equivalent to sending a SIGKILL on Unix platforms.
+    fn kill(&mut self) -> io::Result<process::ExitStatus>;
+}
+
+#[derive(Debug)]
+pub enum RunnerError {
+    Io(io::Error),
+    PrefReader(PrefReaderError),
+}
+
+impl fmt::Display for RunnerError {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        match *self {
+            RunnerError::Io(ref err) => match err.kind() {
+                ErrorKind::NotFound => "no such file or directory".fmt(f),
+                _ => err.fmt(f),
+            },
+            RunnerError::PrefReader(ref err) => err.fmt(f),
+        }
+    }
+}
+
+impl Error for RunnerError {
+    fn cause(&self) -> Option<&dyn Error> {
+        Some(match *self {
+            RunnerError::Io(ref err) => err as &dyn Error,
+            RunnerError::PrefReader(ref err) => err as &dyn Error,
+        })
+    }
+}
+
+impl From<io::Error> for RunnerError {
+    fn from(value: io::Error) -> RunnerError {
+        RunnerError::Io(value)
+    }
+}
+
+impl From<PrefReaderError> for RunnerError {
+    fn from(value: PrefReaderError) -> RunnerError {
+        RunnerError::PrefReader(value)
+    }
+}
+
+#[derive(Debug)]
+pub struct FirefoxProcess {
+    process: Child,
+    // The profile field is not directly used, but it is kept to avoid its
+    // Drop removing the (temporary) profile directory.
+    #[allow(dead_code)]
+    profile: Option<Profile>,
+}
+
+impl RunnerProcess for FirefoxProcess {
+    fn try_wait(&mut self) -> io::Result<Option<process::ExitStatus>> {
+        self.process.try_wait()
+    }
+
+    fn wait(&mut self, timeout: time::Duration) -> io::Result<process::ExitStatus> {
+        let start = time::Instant::now();
+        loop {
+            match self.try_wait() {
+                // child has already exited, reap its exit code
+                Ok(Some(status)) => return Ok(status),
+
+                // child still running and timeout elapsed, kill it
+                Ok(None) if start.elapsed() >= timeout => return self.kill(),
+
+                // child still running, let's give it more time
+                Ok(None) => thread::sleep(time::Duration::from_millis(100)),
+
+                Err(e) => return Err(e),
+            }
+        }
+    }
+
+    fn running(&mut self) -> bool {
+        self.try_wait().unwrap().is_none()
+    }
+
+    fn kill(&mut self) -> io::Result<process::ExitStatus> {
+        match self.try_wait() {
+            // child has already exited, reap its exit code
+            Ok(Some(status)) => Ok(status),
+
+            // child still running, kill it
+            Ok(None) => {
+                debug!("Killing process {}", self.process.id());
+                self.process.kill()?;
+                self.process.wait()
+            }
+
+            Err(e) => Err(e),
+        }
+    }
+}
+
+#[derive(Debug)]
+pub struct FirefoxRunner {
+    path: PathBuf,
+    profile: Option<Profile>,
+    args: Vec<OsString>,
+    envs: HashMap<OsString, OsString>,
+    stdout: Option<Stdio>,
+    stderr: Option<Stdio>,
+}
+
+impl FirefoxRunner {
+    /// Initialise Firefox process runner.
+    ///
+    /// On macOS, `path` can optionally point to an application bundle,
+    /// i.e. _/Applications/Firefox.app_, as well as to an executable program
+    /// such as _/Applications/Firefox.app/Content/MacOS/firefox-bin_.
+    pub fn new(path: &Path, profile: Option<Profile>) -> FirefoxRunner {
+        let mut envs: HashMap<OsString, OsString> = HashMap::new();
+        envs.insert("MOZ_NO_REMOTE".into(), "1".into());
+
+        FirefoxRunner {
+            path: path.to_path_buf(),
+            envs,
+            profile,
+            args: vec![],
+            stdout: None,
+            stderr: None,
+        }
+    }
+}
+
+impl Runner for FirefoxRunner {
+    type Process = FirefoxProcess;
+
+    fn arg<S>(&mut self, arg: S) -> &mut FirefoxRunner
+    where
+        S: AsRef<OsStr>,
+    {
+        self.args.push((&arg).into());
+        self
+    }
+
+    fn args<I, S>(&mut self, args: I) -> &mut FirefoxRunner
+    where
+        I: IntoIterator<Item = S>,
+        S: AsRef<OsStr>,
+    {
+        for arg in args {
+            self.args.push((&arg).into());
+        }
+        self
+    }
+
+    fn env<K, V>(&mut self, key: K, value: V) -> &mut FirefoxRunner
+    where
+        K: AsRef<OsStr>,
+        V: AsRef<OsStr>,
+    {
+        self.envs.insert((&key).into(), (&value).into());
+        self
+    }
+
+    fn envs<I, K, V>(&mut self, envs: I) -> &mut FirefoxRunner
+    where
+        I: IntoIterator<Item = (K, V)>,
+        K: AsRef<OsStr>,
+        V: AsRef<OsStr>,
+    {
+        for (key, value) in envs {
+            self.envs.insert((&key).into(), (&value).into());
+        }
+        self
+    }
+
+    fn stdout<T>(&mut self, stdout: T) -> &mut Self
+    where
+        T: Into<Stdio>,
+    {
+        self.stdout = Some(stdout.into());
+        self
+    }
+
+    fn stderr<T>(&mut self, stderr: T) -> &mut Self
+    where
+        T: Into<Stdio>,
+    {
+        self.stderr = Some(stderr.into());
+        self
+    }
+
+    fn start(mut self) -> Result<FirefoxProcess, RunnerError> {
+        if let Some(ref mut profile) = self.profile {
+            profile.user_prefs()?.write()?;
+        }
+
+        let stdout = self.stdout.unwrap_or_else(Stdio::inherit);
+        let stderr = self.stderr.unwrap_or_else(Stdio::inherit);
+
+        let binary_path = platform::resolve_binary_path(&mut self.path);
+        let mut cmd = Command::new(binary_path);
+        cmd.args(&self.args[..])
+            .envs(&self.envs)
+            .stdout(stdout)
+            .stderr(stderr);
+
+        let mut seen_foreground = false;
+        let mut seen_no_remote = false;
+        let mut seen_profile = false;
+        for arg in self.args.iter() {
+            match arg.into() {
+                Arg::Foreground => seen_foreground = true,
+                Arg::NoRemote => seen_no_remote = true,
+                Arg::Profile | Arg::NamedProfile | Arg::ProfileManager => seen_profile = true,
+                Arg::Marionette
+                | Arg::None
+                | Arg::Other(_)
+                | Arg::RemoteAllowHosts
+                | Arg::RemoteAllowOrigins
+                | Arg::RemoteDebuggingPort => {}
+            }
+        }
+        // -foreground is only supported on Mac, and shouldn't be passed
+        // to Firefox on other platforms (bug 1720502).
+        if cfg!(target_os = "macos") && !seen_foreground {
+            cmd.arg("-foreground");
+        }
+        if !seen_no_remote {
+            cmd.arg("-no-remote");
+        }
+        if let Some(ref profile) = self.profile {
+            if !seen_profile {
+                cmd.arg("-profile").arg(&profile.path);
+            }
+        }
+
+        info!("Running command: {:?}", cmd);
+        let process = cmd.spawn()?;
+        Ok(FirefoxProcess {
+            process,
+            profile: self.profile,
+        })
+    }
+}
+
+#[cfg(all(not(target_os = "macos"), unix))]
+pub mod platform {
+    use crate::path::find_binary;
+    use std::path::PathBuf;
+
+    pub fn resolve_binary_path(path: &mut PathBuf) -> &PathBuf {
+        path
+    }
+
+    fn running_as_snap() -> bool {
+        std::env::var("SNAP_INSTANCE_NAME")
+            .or_else(|_| {
+                // Compatibility for snapd <= 2.35
+                std::env::var("SNAP_NAME")
+            })
+            .map(|name| !name.is_empty())
+            .unwrap_or(false)
+    }
+
+    /// Searches the system path for `firefox`.
+    pub fn firefox_default_path() -> Option<PathBuf> {
+        if running_as_snap() {
+            return Some(PathBuf::from("/snap/firefox/current/firefox.launcher"));
+        }
+        find_binary("firefox")
+    }
+
+    pub fn arg_prefix_char(c: char) -> bool {
+        c == '-'
+    }
+
+    #[cfg(test)]
+    mod tests {
+        use crate::firefox_default_path;
+        use std::env;
+        use std::ops::Drop;
+        use std::path::PathBuf;
+
+        static SNAP_KEY: &str = "SNAP_INSTANCE_NAME";
+        static SNAP_LEGACY_KEY: &str = "SNAP_NAME";
+
+        struct SnapEnvironment {
+            initial_environment: (Option<String>, Option<String>),
+        }
+
+        impl SnapEnvironment {
+            fn new() -> SnapEnvironment {
+                SnapEnvironment {
+                    initial_environment: (env::var(SNAP_KEY).ok(), env::var(SNAP_LEGACY_KEY).ok()),
+                }
+            }
+
+            fn set(&self, value: Option<String>, legacy_value: Option<String>) {
+                fn set_env(key: &str, value: Option<String>) {
+                    match value {
+                        Some(value) => env::set_var(key, value),
+                        None => env::remove_var(key),
+                    }
+                }
+                set_env(SNAP_KEY, value);
+                set_env(SNAP_LEGACY_KEY, legacy_value);
+            }
+        }
+
+        impl Drop for SnapEnvironment {
+            fn drop(&mut self) {
+                self.set(
+                    self.initial_environment.0.clone(),
+                    self.initial_environment.1.clone(),
+                )
+            }
+        }
+
+        #[test]
+        fn test_default_path() {
+            let snap_path = Some(PathBuf::from("/snap/firefox/current/firefox.launcher"));
+
+            let snap_env = SnapEnvironment::new();
+
+            snap_env.set(None, None);
+            assert_ne!(firefox_default_path(), snap_path);
+
+            snap_env.set(Some("value".into()), None);
+            assert_eq!(firefox_default_path(), snap_path);
+
+            snap_env.set(None, Some("value".into()));
+            assert_eq!(firefox_default_path(), snap_path);
+        }
+    }
+}
+
+#[cfg(target_os = "macos")]
+pub mod platform {
+    use crate::path::{find_binary, is_binary};
+    use dirs;
+    use plist::Value;
+    use std::path::PathBuf;
+
+    /// Searches for the binary file inside the path passed as parameter.
+    /// If the binary is not found, the path remains unaltered.
+    /// Else, it gets updated by the new binary path.
+    pub fn resolve_binary_path(path: &mut PathBuf) -> &PathBuf {
+        if path.as_path().is_dir() {
+            let mut info_plist = path.clone();
+            info_plist.push("Contents");
+            info_plist.push("Info.plist");
+            if let Ok(plist) = Value::from_file(&info_plist) {
+                if let Some(dict) = plist.as_dictionary() {
+                    if let Some(Value::String(s)) = dict.get("CFBundleExecutable") {
+                        path.push("Contents");
+                        path.push("MacOS");
+                        path.push(s);
+                    }
+                }
+            }
+        }
+        path
+    }
+
+    /// Searches the system path for `firefox-bin`, then looks for
+    /// `Applications/Firefox.app/Contents/MacOS/firefox-bin` as well
+    /// as `Applications/Firefox Nightly.app/Contents/MacOS/firefox-bin`
+    /// under both `/` (system root) and the user home directory.
+    pub fn firefox_default_path() -> Option<PathBuf> {
+        if let Some(path) = find_binary("firefox-bin") {
+            return Some(path);
+        }
+
+        let home = dirs::home_dir();
+        for &(prefix_home, trial_path) in [
+            (
+                false,
+                "/Applications/Firefox.app/Contents/MacOS/firefox-bin",
+            ),
+            (true, "Applications/Firefox.app/Contents/MacOS/firefox-bin"),
+            (
+                false,
+                "/Applications/Firefox Nightly.app/Contents/MacOS/firefox-bin",
+            ),
+            (
+                true,
+                "Applications/Firefox Nightly.app/Contents/MacOS/firefox-bin",
+            ),
+        ]
+        .iter()
+        {
+            let path = match (home.as_ref(), prefix_home) {
+                (Some(home_dir), true) => home_dir.join(trial_path),
+                (None, true) => continue,
+                (_, false) => PathBuf::from(trial_path),
+            };
+            if is_binary(&path) {
+                return Some(path);
+            }
+        }
+
+        None
+    }
+
+    pub fn arg_prefix_char(c: char) -> bool {
+        c == '-'
+    }
+}
+
+#[cfg(target_os = "windows")]
+pub mod platform {
+    use crate::path::{find_binary, is_binary};
+    use std::io::Error;
+    use std::path::PathBuf;
+    use winreg::enums::*;
+    use winreg::RegKey;
+
+    pub fn resolve_binary_path(path: &mut PathBuf) -> &PathBuf {
+        path
+    }
+
+    /// Searches the Windows registry, then the system path for `firefox.exe`.
+    ///
+    /// It _does not_ currently check the `HKEY_CURRENT_USER` tree.
+    pub fn firefox_default_path() -> Option<PathBuf> {
+        if let Ok(Some(path)) = firefox_registry_path() {
+            if is_binary(&path) {
+                return Some(path);
+            }
+        };
+        find_binary("firefox.exe")
+    }
+
+    fn firefox_registry_path() -> Result<Option<PathBuf>, Error> {
+        let hklm = RegKey::predef(HKEY_LOCAL_MACHINE);
+        for subtree_key in ["SOFTWARE", "SOFTWARE\\WOW6432Node"].iter() {
+            let subtree = hklm.open_subkey_with_flags(subtree_key, KEY_READ)?;
+            let mozilla_org = match subtree.open_subkey_with_flags("mozilla.org\\Mozilla", KEY_READ)
+            {
+                Ok(val) => val,
+                Err(_) => continue,
+            };
+            let current_version: String = mozilla_org.get_value("CurrentVersion")?;
+            let mozilla = subtree.open_subkey_with_flags("Mozilla", KEY_READ)?;
+            for key_res in mozilla.enum_keys() {
+                let key = key_res?;
+                let section_data = mozilla.open_subkey_with_flags(&key, KEY_READ)?;
+                let version: Result<String, _> = section_data.get_value("GeckoVer");
+                if let Ok(ver) = version {
+                    if ver == current_version {
+                        let mut bin_key = key.to_owned();
+                        bin_key.push_str("\\bin");
+                        if let Ok(bin_subtree) = mozilla.open_subkey_with_flags(bin_key, KEY_READ) {
+                            let path_to_exe: Result<String, _> = bin_subtree.get_value("PathToExe");
+                            if let Ok(path_to_exe) = path_to_exe {
+                                let path = PathBuf::from(path_to_exe);
+                                if is_binary(&path) {
+                                    return Ok(Some(path));
+                                }
+                            }
+                        }
+                    }
+                }
+            }
+        }
+        Ok(None)
+    }
+
+    pub fn arg_prefix_char(c: char) -> bool {
+        c == '/' || c == '-'
+    }
+}
+
+#[cfg(not(any(unix, target_os = "windows")))]
+pub mod platform {
+    use std::path::PathBuf;
+
+    /// Returns an unaltered path for all operating systems other than macOS.
+    pub fn resolve_binary_path(path: &mut PathBuf) -> &PathBuf {
+        path
+    }
+
+    /// Returns `None` for all other operating systems than Linux, macOS, and
+    /// Windows.
+    pub fn firefox_default_path() -> Option<PathBuf> {
+        None
+    }
+
+    pub fn arg_prefix_char(c: char) -> bool {
+        c == '-'
+    }
+}
diff --git a/testing/mozbase/rust/mozversion/Cargo.toml b/testing/mozbase/rust/mozversion/Cargo.toml
new file mode 100644
index 0000000000..09ca6f3c61
--- /dev/null
+++ b/testing/mozbase/rust/mozversion/Cargo.toml
@@ -0,0 +1,17 @@
+[package]
+edition = "2018"
+name = "mozversion"
+version = "0.5.0"
+authors = ["Mozilla"]
+description = "Utility for accessing Firefox version metadata"
+keywords = [
+    "firefox",
+    "mozilla",
+]
+license = "MPL-2.0"
+repository = "https://hg.mozilla.org/mozilla-central/file/tip/testing/mozbase/rust/mozversion"
+
+[dependencies]
+regex = { version = "1", default-features = false, features = ["perf", "std"] }
+rust-ini = "0.10"
+semver = "1.0"
diff --git a/testing/mozbase/rust/mozversion/src/lib.rs b/testing/mozbase/rust/mozversion/src/lib.rs
new file mode 100644
index 0000000000..75a40fe779
--- /dev/null
+++ b/testing/mozbase/rust/mozversion/src/lib.rs
@@ -0,0 +1,426 @@
+#![forbid(unsafe_code)]
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+extern crate ini;
+extern crate regex;
+extern crate semver;
+
+use crate::platform::ini_path;
+use ini::Ini;
+use regex::Regex;
+use std::default::Default;
+use std::error;
+use std::fmt::{self, Display, Formatter};
+use std::path::Path;
+use std::process::{Command, Stdio};
+use std::str::{self, FromStr};
+
+/// Details about the version of a Firefox build.
+#[derive(Clone, Default)]
+pub struct AppVersion {
+    /// Unique date-based id for a build
+    pub build_id: Option<String>,
+    /// Channel name
+    pub code_name: Option<String>,
+    /// Version number e.g. 55.0a1
+    pub version_string: Option<String>,
+    /// Url of the respoistory from which the build was made
+    pub source_repository: Option<String>,
+    /// Commit ID of the build
+    pub source_stamp: Option<String>,
+}
+
+impl AppVersion {
+    pub fn new() -> AppVersion {
+        Default::default()
+    }
+
+    fn update_from_application_ini(&mut self, ini_file: &Ini) {
+        if let Some(section) = ini_file.section(Some("App")) {
+            if let Some(build_id) = section.get("BuildID") {
+                self.build_id = Some(build_id.clone());
+            }
+            if let Some(code_name) = section.get("CodeName") {
+                self.code_name = Some(code_name.clone());
+            }
+            if let Some(version) = section.get("Version") {
+                self.version_string = Some(version.clone());
+            }
+            if let Some(source_repository) = section.get("SourceRepository") {
+                self.source_repository = Some(source_repository.clone());
+            }
+            if let Some(source_stamp) = section.get("SourceStamp") {
+                self.source_stamp = Some(source_stamp.clone());
+            }
+        }
+    }
+
+    fn update_from_platform_ini(&mut self, ini_file: &Ini) {
+        if let Some(section) = ini_file.section(Some("Build")) {
+            if let Some(build_id) = section.get("BuildID") {
+                self.build_id = Some(build_id.clone());
+            }
+            if let Some(version) = section.get("Milestone") {
+                self.version_string = Some(version.clone());
+            }
+            if let Some(source_repository) = section.get("SourceRepository") {
+                self.source_repository = Some(source_repository.clone());
+            }
+            if let Some(source_stamp) = section.get("SourceStamp") {
+                self.source_stamp = Some(source_stamp.clone());
+            }
+        }
+    }
+
+    pub fn version(&self) -> Option<Version> {
+        self.version_string
+            .as_ref()
+            .and_then(|x| Version::from_str(x).ok())
+    }
+}
+
+#[derive(Default, Clone)]
+/// Version number information
+pub struct Version {
+    /// Major version number (e.g. 55 in 55.0)
+    pub major: u64,
+    /// Minor version number (e.g. 1 in 55.1)
+    pub minor: u64,
+    /// Patch version number (e.g. 2 in 55.1.2)
+    pub patch: u64,
+    /// Prerelase information (e.g. Some(("a", 1)) in 55.0a1)
+    pub pre: Option<(String, u64)>,
+    /// Is build an ESR build
+    pub esr: bool,
+}
+
+impl Version {
+    fn to_semver(&self) -> semver::Version {
+        // The way the semver crate handles prereleases isn't what we want here
+        // This should be fixed in the long term by implementing our own comparison
+        // operators, but for now just act as if prerelease metadata was missing,
+        // otherwise it is almost impossible to use this with nightly
+        semver::Version {
+            major: self.major,
+            minor: self.minor,
+            patch: self.patch,
+            pre: semver::Prerelease::EMPTY,
+            build: semver::BuildMetadata::EMPTY,
+        }
+    }
+
+    pub fn matches(&self, version_req: &str) -> VersionResult<bool> {
+        let req = semver::VersionReq::parse(version_req)?;
+        Ok(req.matches(&self.to_semver()))
+    }
+}
+
+impl FromStr for Version {
+    type Err = Error;
+
+    fn from_str(version_string: &str) -> VersionResult<Version> {
+        let mut version: Version = Default::default();
+        let version_re = Regex::new(r"^(?P<major>[[:digit:]]+)\.(?P<minor>[[:digit:]]+)(?:\.(?P<patch>[[:digit:]]+))?(?:(?P<esr>esr)|(?P<pre0>[a-z]+)(?P<pre1>[[:digit:]]*))?$").unwrap();
+        if let Some(captures) = version_re.captures(version_string) {
+            match captures
+                .name("major")
+                .and_then(|x| u64::from_str(x.as_str()).ok())
+            {
+                Some(x) => version.major = x,
+                None => return Err(Error::VersionError("No major version number found".into())),
+            }
+            match captures
+                .name("minor")
+                .and_then(|x| u64::from_str(x.as_str()).ok())
+            {
+                Some(x) => version.minor = x,
+                None => return Err(Error::VersionError("No minor version number found".into())),
+            }
+            if let Some(x) = captures
+                .name("patch")
+                .and_then(|x| u64::from_str(x.as_str()).ok())
+            {
+                version.patch = x
+            }
+            if captures.name("esr").is_some() {
+                version.esr = true;
+            }
+            if let Some(pre_0) = captures.name("pre0").map(|x| x.as_str().to_string()) {
+                if captures.name("pre1").is_some() {
+                    if let Some(pre_1) = captures
+                        .name("pre1")
+                        .and_then(|x| u64::from_str(x.as_str()).ok())
+                    {
+                        version.pre = Some((pre_0, pre_1))
+                    } else {
+                        return Err(Error::VersionError(
+                            "Failed to convert prelease number to u64".into(),
+                        ));
+                    }
+                } else {
+                    return Err(Error::VersionError(
+                        "Failed to convert prelease number to u64".into(),
+                    ));
+                }
+            }
+        } else {
+            return Err(Error::VersionError(format!(
+                "Failed to parse {} as version string",
+                version_string
+            )));
+        }
+        Ok(version)
+    }
+}
+
+impl Display for Version {
+    fn fmt(&self, f: &mut Formatter) -> fmt::Result {
+        match self.patch {
+            0 => write!(f, "{}.{}", self.major, self.minor)?,
+            _ => write!(f, "{}.{}.{}", self.major, self.minor, self.patch)?,
+        }
+        if self.esr {
+            write!(f, "esr")?;
+        }
+        if let Some(ref pre) = self.pre {
+            write!(f, "{}{}", pre.0, pre.1)?;
+        };
+        Ok(())
+    }
+}
+
+/// Determine the version of Firefox using associated metadata files.
+///
+/// Given the path to a Firefox binary, read the associated application.ini
+/// and platform.ini files to extract information about the version of Firefox
+/// at that path.
+pub fn firefox_version(binary: &Path) -> VersionResult<AppVersion> {
+    let mut version = AppVersion::new();
+    let mut updated = false;
+
+    if let Some(dir) = ini_path(binary) {
+        let mut application_ini = dir.clone();
+        application_ini.push("application.ini");
+
+        if Path::exists(&application_ini) {
+            let ini_file = Ini::load_from_file(application_ini).ok();
+            if let Some(ini) = ini_file {
+                updated = true;
+                version.update_from_application_ini(&ini);
+            }
+        }
+
+        let mut platform_ini = dir;
+        platform_ini.push("platform.ini");
+
+        if Path::exists(&platform_ini) {
+            let ini_file = Ini::load_from_file(platform_ini).ok();
+            if let Some(ini) = ini_file {
+                updated = true;
+                version.update_from_platform_ini(&ini);
+            }
+        }
+
+        if !updated {
+            return Err(Error::MetadataError(
+                "Neither platform.ini nor application.ini found".into(),
+            ));
+        }
+    } else {
+        return Err(Error::MetadataError("Invalid binary path".into()));
+    }
+    Ok(version)
+}
+
+/// Determine the version of Firefox by executing the binary.
+///
+/// Given the path to a Firefox binary, run firefox --version and extract the
+/// version string from the output
+pub fn firefox_binary_version(binary: &Path) -> VersionResult<Version> {
+    let output = Command::new(binary)
+        .args(["--version"])
+        .stdout(Stdio::piped())
+        .spawn()
+        .and_then(|child| child.wait_with_output())
+        .ok();
+
+    if let Some(x) = output {
+        let output_str = str::from_utf8(&x.stdout)
+            .map_err(|_| Error::VersionError("Couldn't parse version output as UTF8".into()))?;
+        parse_binary_version(output_str)
+    } else {
+        Err(Error::VersionError("Running binary failed".into()))
+    }
+}
+
+fn parse_binary_version(version_str: &str) -> VersionResult<Version> {
+    let version_regexp = Regex::new(r#"Mozilla Firefox[[:space:]]+(?P<version>.+)"#)
+        .expect("Error parsing version regexp");
+
+    let version_match = version_regexp
+        .captures(version_str)
+        .and_then(|captures| captures.name("version"))
+        .ok_or_else(|| Error::VersionError("--version output didn't match expectations".into()))?;
+
+    Version::from_str(version_match.as_str())
+}
+
+#[derive(Clone, Debug)]
+pub enum Error {
+    /// Error parsing a version string
+    VersionError(String),
+    /// Error reading application metadata
+    MetadataError(String),
+    /// Error processing a string as a semver comparator
+    SemVerError(String),
+}
+
+impl Display for Error {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        match *self {
+            Error::VersionError(ref x) => {
+                "VersionError: ".fmt(f)?;
+                x.fmt(f)
+            }
+            Error::MetadataError(ref x) => {
+                "MetadataError: ".fmt(f)?;
+                x.fmt(f)
+            }
+            Error::SemVerError(ref e) => {
+                "SemVerError: ".fmt(f)?;
+                e.fmt(f)
+            }
+        }
+    }
+}
+
+impl From<semver::Error> for Error {
+    fn from(err: semver::Error) -> Error {
+        Error::SemVerError(err.to_string())
+    }
+}
+
+impl error::Error for Error {
+    fn cause(&self) -> Option<&dyn error::Error> {
+        None
+    }
+}
+
+pub type VersionResult<T> = Result<T, Error>;
+
+#[cfg(target_os = "macos")]
+mod platform {
+    use std::path::{Path, PathBuf};
+
+    pub fn ini_path(binary: &Path) -> Option<PathBuf> {
+        binary
+            .canonicalize()
+            .ok()
+            .as_ref()
+            .and_then(|dir| dir.parent())
+            .and_then(|dir| dir.parent())
+            .map(|dir| dir.join("Resources"))
+    }
+}
+
+#[cfg(not(target_os = "macos"))]
+mod platform {
+    use std::path::{Path, PathBuf};
+
+    pub fn ini_path(binary: &Path) -> Option<PathBuf> {
+        binary
+            .canonicalize()
+            .ok()
+            .as_ref()
+            .and_then(|dir| dir.parent())
+            .map(|dir| dir.to_path_buf())
+    }
+}
+
+#[cfg(test)]
+mod test {
+    use super::{parse_binary_version, Version};
+    use std::str::FromStr;
+
+    fn parse_version(input: &str) -> String {
+        Version::from_str(input).unwrap().to_string()
+    }
+
+    fn compare(version: &str, comparison: &str) -> bool {
+        let v = Version::from_str(version).unwrap();
+        v.matches(comparison).unwrap()
+    }
+
+    #[test]
+    fn test_parser() {
+        assert!(parse_version("50.0a1") == "50.0a1");
+        assert!(parse_version("50.0.1a1") == "50.0.1a1");
+        assert!(parse_version("50.0.0") == "50.0");
+        assert!(parse_version("78.0.11esr") == "78.0.11esr");
+    }
+
+    #[test]
+    fn test_matches() {
+        assert!(compare("50.0", "=50"));
+        assert!(compare("50.1", "=50"));
+        assert!(compare("50.1", "=50.1"));
+        assert!(compare("50.1.1", "=50.1"));
+        assert!(compare("50.0.0", "=50.0.0"));
+        assert!(compare("51.0.0", ">50"));
+        assert!(compare("49.0", "<50"));
+        assert!(compare("50.0", "<50.1"));
+        assert!(compare("50.0.0", "<50.0.1"));
+        assert!(!compare("50.1.0", ">50"));
+        assert!(!compare("50.1.0", "<50"));
+        assert!(compare("50.1.0", ">=50,<51"));
+        assert!(compare("50.0a1", ">49.0"));
+        assert!(compare("50.0a2", "=50"));
+        assert!(compare("78.1.0esr", ">=78"));
+        assert!(compare("78.1.0esr", "<79"));
+        assert!(compare("78.1.11esr", "<79"));
+        // This is the weird one
+        assert!(!compare("50.0a2", ">50.0"));
+    }
+
+    #[test]
+    fn test_binary_parser() {
+        assert!(
+            parse_binary_version("Mozilla Firefox 50.0a1")
+                .unwrap()
+                .to_string()
+                == "50.0a1"
+        );
+        assert!(
+            parse_binary_version("Mozilla Firefox 50.0.1a1")
+                .unwrap()
+                .to_string()
+                == "50.0.1a1"
+        );
+        assert!(
+            parse_binary_version("Mozilla Firefox 50.0.0")
+                .unwrap()
+                .to_string()
+                == "50.0"
+        );
+        assert!(
+            parse_binary_version("Mozilla Firefox 78.0.11esr")
+                .unwrap()
+                .to_string()
+                == "78.0.11esr"
+        );
+        assert!(
+            parse_binary_version("Mozilla Firefox 78.0esr")
+                .unwrap()
+                .to_string()
+                == "78.0esr"
+        );
+        assert!(
+            parse_binary_version("Mozilla Firefox 78.0")
+                .unwrap()
+                .to_string()
+                == "78.0"
+        );
+    }
+}