--- a/testing/geckodriver/.travis.yml
+++ b/testing/geckodriver/.travis.yml
@@ -1,36 +1,41 @@
 language: generic
 
 matrix:
   include:
-    - env: TARGET=armv7-unknown-linux-gnueabihf
+    - os: linux
+      env: TARGET=armv7-unknown-linux-gnueabihf
       addons:
         apt:
           packages: &armhf
           - gcc-arm-linux-gnueabihf
           - libc6-armhf-cross
           - libc6-dev-armhf-cross
-    - env: TARGET=x86_64-unknown-linux-musl
+    - os: linux
+      env: TARGET=x86_64-unknown-linux-musl
       dist: trusty
       sudo: required
       addons:
         apt:
           packages:
           - musl-tools
           - libbz2-dev
-    - env: TARGET=x86_64-pc-windows-gnu
+    - os: linux
+      env: TARGET=x86_64-pc-windows-gnu
       dist: trusty
       addons:
         apt:
           packages:
           - gcc-mingw-w64
           - gcc-mingw-w64-x86-64
           - binutils-mingw-w64-x86-64
           - libbz2-dev
+    - os: osx
+      env: TARGET=x86_64-apple-darwin
 
 install:
   - export PATH="$PATH:$HOME/.cargo/bin"
   - curl https://sh.rustup.rs -sSf | sh -s -- -y --default-toolchain=stable
   - rustc -V
   - cargo -V
 
 script:
@@ -43,14 +48,15 @@ branches:
 deploy:
   provider: releases
   api_key:
     secure:
       OY6y0xRhlGSBH+3+7+7K6s4pp0Tf3BA61NAubEK4gpO23AKfyJUK+vqqCbdo06Z0E4QO4O1ke6fot7Gq9EdxJmsl/Kk5LDd9Rv3BXSYdjPupzs7coYuD8wv10NfAX6ETd9ITyPim2Zq6bq8nx1S2ESTpos/js1HCtVW3nrlCV58=
   skip_cleanup: true
   file:
     - "geckodriver-$TRAVIS_TAG.tar.gz"
-    - "geckodriver-$TRAVIS_TAG-arm7hf.zip"
+    - "geckodriver-$TRAVIS_TAG-arm7hf.tar.gz"
+    - "geckodriver-$TRAVIS_TAG-linux64.tar.gz"
+    - "geckodriver-$TRAVIS_TAG-mac.tar.gz"
     - "geckodriver-$TRAVIS_TAG-win64.zip"
-    - "geckodriver-$TRAVIS_TAG-linux64.tar.gz"
   on:
     tags: true
     repo: mozilla/geckodriver

--- a/testing/geckodriver/ci.sh
+++ b/testing/geckodriver/ci.sh
@@ -1,140 +1,143 @@
 set -ex
 
 # Add provided target to current Rust toolchain if it is not already
 # the default or installed.
 rustup_target_add() {
-	if ! rustup target list | grep -E "$1 \((default|installed)\)"
-	then
-		rustup target add $1
-	fi
+    if ! rustup target list | grep -E "$1 \((default|installed)\)"
+    then
+        rustup target add $1
+    fi
 }
 
 # Configure rustc target for cross compilation.  Provided with a build
 # target, this will determine which linker to use for cross compilation.
 cargo_config() {
-	local prefix
+    local prefix
 
-	case "$TARGET" in
-	aarch64-unknown-linux-gnu)
-		prefix=aarch64-linux-gnu
-		;;
-	arm*-unknown-linux-gnueabihf)
-		prefix=arm-linux-gnueabihf
-		;;
-	arm-unknown-linux-gnueabi)
-		prefix=arm-linux-gnueabi
-		;;
-	mipsel-unknown-linux-musl)
-		prefix=mipsel-openwrt-linux
-		;;
-	x86_64-pc-windows-gnu)
-		prefix=x86_64-w64-mingw32
-		;;
-	*)
-		return
-		;;
-	esac
+    case "$TARGET" in
+    aarch64-unknown-linux-gnu)
+        prefix=aarch64-linux-gnu
+        ;;
+    arm*-unknown-linux-gnueabihf)
+        prefix=arm-linux-gnueabihf
+        ;;
+    arm-unknown-linux-gnueabi)
+        prefix=arm-linux-gnueabi
+        ;;
+    mipsel-unknown-linux-musl)
+        prefix=mipsel-openwrt-linux
+        ;;
+    x86_64-pc-windows-gnu)
+        prefix=x86_64-w64-mingw32
+        ;;
+    *)
+        return
+        ;;
+    esac
 
-	mkdir -p ~/.cargo
-	cat >>~/.cargo/config <<EOF
+    mkdir -p ~/.cargo
+    cat >>~/.cargo/config <<EOF
 [target.$TARGET]
 linker = "$prefix-gcc"
 EOF
 }
 
 # Build current crate for given target and print file type information.
 # If the second argument is set, a release build will be made.
 cargo_build() {
-	local mode
-	if [ -z "$2" ]
-	then
-		mode=debug
-	else
-		mode=release
-	fi
+    local mode
+    if [ -z "$2" ]
+    then
+        mode=debug
+    else
+        mode=release
+    fi
 
-	local modeflag
-	if [ "$mode" == "release" ]
-	then
-		modeflag=--release
-	fi
-	
-	cargo build --target $1 $modeflag
+    local modeflag
+    if [ "$mode" == "release" ]
+    then
+        modeflag=--release
+    fi
 
-	file $(get_binary $1 $mode)
+    cargo build --target $1 $modeflag
+
+    file $(get_binary $1 $mode)
 }
 
 # Run current crate's tests if the current system supports it.
 cargo_test() {
-	if echo "$1" | grep -E "(i686|x86_64)-unknown-linux-(gnu|musl)"
-	then
-		cargo test --target $1
-	fi
+    if echo "$1" | grep -E "(i686|x86_64)-unknown-linux-(gnu|musl)|darwin"
+    then
+        cargo test --target $1
+    fi
 }
 
 # Returns relative path to binary
 # based on build target and type ("release"/"debug").
 get_binary() {
-	local ext
-	if [[ "$1" =~ "windows" ]]
-	then
-		ext=".exe"
-	fi
-	echo "target/$1/$2/geckodriver$ext"
+    local ext
+    if [[ "$1" =~ "windows" ]]
+    then
+        ext=".exe"
+    fi
+    echo "target/$1/$2/geckodriver$ext"
 }
 
 # Create a compressed archive of the binary
 # for the given given git tag, build target, and build type.
 package_binary() {
-	local target
-	case "$2" in
-	armv7-unknown-linux-gnueabihf)
-		target=arm7hf
-		;;
-	x86_64-pc-windows-gnu)
-		target=win64
-		;;
-	x86_64-unknown-linux-musl)
-		target=linux64
-		;;
-	esac
+    local target
+    case "$2" in
+    armv7-unknown-linux-gnueabihf)
+        target=arm7hf
+        ;;
+    x86_64-pc-windows-gnu)
+        target=win64
+        ;;
+    x86_64-unknown-linux-musl)
+        target=linux64
+        ;;
+    x86_64-apple-darwin)
+        target=mac
+        ;;
+    esac
 
-	local bin
-	bin=$(get_binary $2 $3)
-	cp $bin .
+    local bin
+    bin=$(get_binary $2 $3)
+    cp $bin .
 
-	if [[ "$2" =~ "windows" ]]
-	then
-		zip geckodriver-$1-$target.zip geckodriver.exe
-		file geckodriver-$1-$target.zip
-	else
-		tar zcvf geckodriver-$1-$target.tar.gz geckodriver
-		file geckodriver-$1-$target.tar.gz
-	fi
+    if [[ "$2" =~ "windows" ]]
+    then
+        zip geckodriver-$1-$target.zip geckodriver.exe
+        file geckodriver-$1-$target.zip
+    else
+        tar zcvf geckodriver-$1-$target.tar.gz geckodriver
+        file geckodriver-$1-$target.tar.gz
+    fi
 }
 
 # Create a compressed archive of the source code
 # for the given git tag.
 package_source() {
-	git archive --format=tar --prefix="geckodriver-$1/" $1 | \
-		gzip >geckodriver-$1.tar.gz
+    git archive --format=tar --prefix="geckodriver-$1/" $1 | \
+        gzip >geckodriver-$1.tar.gz
 }
 
 main() {
-	rustup_target_add $TARGET
+    rustup_target_add $TARGET
 
-	cargo_config $TARGET
-	cargo_build $TARGET
-	cargo_test $TARGET
+    cargo_config $TARGET
+    cargo_build $TARGET
+    cargo_test $TARGET
 
-	# when something is tagged,
-	# also create a release build and package it
-	if [ ! -z "$TRAVIS_TAG" ]
-	then
-		cargo_build $TARGET 1
-		package_binary $TRAVIS_TAG $TARGET "release"
-		package_source $TRAVIS_TAG
-	fi
+    # when something is tagged,
+    # also create a release build and package it
+    if [ ! -z "$TRAVIS_TAG" ]
+    then
+        cargo_build $TARGET 1
+        package_binary $TRAVIS_TAG $TARGET "release"
+        package_source $TRAVIS_TAG
+    fi
 }
 
 main