diff --git a/.github/workflows/scripts.yml b/.github/workflows/scripts.yml
new file mode 100644
index 0000000000000000000000000000000000000000..47df18d6f17ab74fef491d8fcf97b87ce71ec3cf
--- /dev/null
+++ b/.github/workflows/scripts.yml
@@ -0,0 +1,27 @@
+name: Script unit tests
+
+on:
+  push:
+    branches:
+      - main
+    paths:
+      - "installer.sh"
+  pull_request:
+    branches:
+      - main
+
+jobs:
+  test:
+    name: Run script unit tests
+    runs-on: ubuntu-latest
+    # This runs on Alpine to make sure we're testing with actual sh.
+    container: "alpine:3.14"
+    steps:
+      - name: Checkout repo
+        uses: actions/checkout@v2
+
+      - name: Install bats
+        run: apk add bats
+
+      - name: Run script unit tests
+        run: ./ci/dev/test-scripts.sh
diff --git a/ci/dev/test-scripts.sh b/ci/dev/test-scripts.sh
new file mode 100755
index 0000000000000000000000000000000000000000..ebe1efa8ed2257152631ece0ae1966aadf4e83c7
--- /dev/null
+++ b/ci/dev/test-scripts.sh
@@ -0,0 +1,9 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+main() {
+  cd "$(dirname "$0")/../.."
+  bats ./test/scripts
+}
+
+main "$@"
diff --git a/docs/CONTRIBUTING.md b/docs/CONTRIBUTING.md
index d4bf6f07a10b55014475281b5d7d2ec8a8bd1163..691c9f1f2ac14ef68f3af43be8ec5b2416081776 100644
--- a/docs/CONTRIBUTING.md
+++ b/docs/CONTRIBUTING.md
@@ -44,6 +44,8 @@ Here is what is needed:
   - Get this by running `apt-get install -y build-essential`
 - `rsync` and `unzip`
   - Used for code-server releases
+- `bats`
+  - Used to run script unit tests
 
 ## Creating pull requests
 
diff --git a/package.json b/package.json
index 51be2d53fa57811e628466d28d5f8caf8f4a19d5..fca00efdf0d32f2b2ab7c6d07cdd4bb47864ff7c 100644
--- a/package.json
+++ b/package.json
@@ -20,6 +20,7 @@
     "test:e2e": "./ci/dev/test-e2e.sh",
     "test:standalone-release": "./ci/build/test-standalone-release.sh",
     "test:unit": "./ci/dev/test-unit.sh",
+    "test:scripts": "./ci/dev/test-scripts.sh",
     "package": "./ci/build/build-packages.sh",
     "postinstall": "./ci/dev/postinstall.sh",
     "update:vscode": "./ci/dev/update-vscode.sh",
diff --git a/test/scripts/install.bats b/test/scripts/install.bats
new file mode 100644
index 0000000000000000000000000000000000000000..651236b7a8dc89930ba8414c3d7600c04595bc84
--- /dev/null
+++ b/test/scripts/install.bats
@@ -0,0 +1,163 @@
+#!/usr/bin/env bats
+
+SCRIPT_NAME="install.sh"
+SCRIPT="$BATS_TEST_DIRNAME/../../$SCRIPT_NAME"
+
+# Override version so it doesn't have to curl and to avoid caching in case the
+# user already has the latest version installed.
+export VERSION="9999.99.9"
+
+function should-use-deb() {
+  DISTRO=$1 ARCH=$2 OS=linux run "$SCRIPT" --dry-run
+  [ "$status" -eq 0 ]
+  [ "${lines[1]}" = "Installing v$VERSION of the $2 deb package from GitHub." ]
+  [ "${lines[-5]}" = "deb package has been installed." ]
+}
+
+function should-use-rpm() {
+  DISTRO=$1 ARCH=$2 OS=linux run "$SCRIPT" --dry-run
+  [ "$status" -eq 0 ]
+  [ "${lines[1]}" = "Installing v$VERSION of the $2 rpm package from GitHub." ]
+  [ "${lines[-5]}" = "rpm package has been installed." ]
+}
+
+function should-fallback-npm() {
+  YARN_PATH=true DISTRO=$1 ARCH=$2 OS=linux run "$SCRIPT" --dry-run
+  [ "$status" -eq 0 ]
+  [ "${lines[1]}" = "No standalone releases for $2." ]
+  [ "${lines[2]}" = "Falling back to installation from npm." ]
+  [ "${lines[3]}" = "Installing latest from npm." ]
+  [ "${lines[-5]}" = "npm package has been installed." ]
+}
+
+function should-use-npm() {
+  YARN_PATH=true DISTRO=$1 ARCH=$2 OS=linux run "$SCRIPT" --dry-run
+  [ "$status" -eq 0 ]
+  [ "${lines[1]}" = "Installing latest from npm." ]
+  [ "${lines[-5]}" = "npm package has been installed." ]
+}
+
+function should-use-aur() {
+  DISTRO=$1 ARCH=$2 OS=linux run "$SCRIPT" --dry-run
+  [ "$status" -eq 0 ]
+  [ "${lines[1]}" = "Installing latest from the AUR." ]
+  [ "${lines[-5]}" = "AUR package has been installed." ]
+}
+
+function should-fallback-npm-brew() {
+  YARN_PATH=true BREW_PATH= OS=macos ARCH=$1 run "$SCRIPT" --dry-run
+  [ "$status" -eq 0 ]
+  [ "${lines[1]}" = "Homebrew not installed." ]
+  [ "${lines[2]}" = "Falling back to standalone installation." ]
+  [ "${lines[3]}" = "No standalone releases for $1." ]
+  [ "${lines[4]}" = "Falling back to installation from npm." ]
+  [ "${lines[5]}" = "Installing latest from npm." ]
+  [ "${lines[-5]}" = "npm package has been installed." ]
+}
+
+function should-use-brew() {
+  BREW_PATH=true OS=macos ARCH=$1 run "$SCRIPT" --dry-run
+  [ "$status" -eq 0 ]
+  [ "${lines[1]}" = "Installing latest from Homebrew." ]
+  [ "${lines[-3]}" = "Brew release has been installed." ]
+}
+
+function should-use-standalone() {
+  DISTRO=$1 ARCH=$2 OS=$3 run "$SCRIPT" --method standalone --dry-run
+  [ "$status" -eq 0 ]
+  [ "${lines[1]}" = "Installing v$VERSION of the $2 release from GitHub." ]
+  [[ "${lines[-5]}" = "Standalone release has been installed"* ]]
+}
+
+@test "$SCRIPT_NAME: usage with --help" {
+  run "$SCRIPT" --help
+  [ "$status" -eq 0 ]
+  [ "${lines[0]}" = "Installs code-server." ]
+  [[ "${lines[-1]}" = "More installation docs are at"* ]]
+}
+
+# These use the deb but fall back to npm for unsupported architectures.
+@test "$SCRIPT_NAME: debian arm64" {
+  should-use-deb "debian" "arm64"
+}
+@test "$SCRIPT_NAME: debian amd64" {
+  should-use-deb "debian" "amd64"
+}
+@test "$SCRIPT_NAME: debian i386" {
+  should-fallback-npm "debian" "i386"
+}
+
+# These use the rpm but fall back to npm for unsupported architectures.
+@test "$SCRIPT_NAME: fedora arm64" {
+  should-use-rpm "fedora" "arm64"
+}
+@test "$SCRIPT_NAME: fedora amd64" {
+  should-use-rpm "fedora" "amd64"
+}
+@test "$SCRIPT_NAME: fedora i386" {
+  should-fallback-npm "fedora" "i386"
+}
+
+# These always use npm regardless of the architecture.
+@test "$SCRIPT_NAME: alpine arm64" {
+  should-use-npm "alpine" "arm64"
+}
+@test "$SCRIPT_NAME: alpine amd64" {
+  should-use-npm "alpine" "amd64"
+}
+@test "$SCRIPT_NAME: alpine i386" {
+  should-use-npm "alpine" "i386"
+}
+
+@test "$SCRIPT_NAME: freebsd arm64" {
+  should-use-npm "freebsd" "arm64"
+}
+@test "$SCRIPT_NAME: freebsd amd64" {
+  should-use-npm "freebsd" "amd64"
+}
+@test "$SCRIPT_NAME: freebsd i386" {
+  should-use-npm "freebsd" "i386"
+}
+
+# Arch Linux uses AUR but falls back to npm for unsuppported architectures.
+@test "$SCRIPT_NAME: arch arm64" {
+  should-use-aur "arch" "arm64"
+}
+@test "$SCRIPT_NAME: arch amd64" {
+  should-use-aur "arch" "amd64"
+}
+@test "$SCRIPT_NAME: arch i386" {
+  should-fallback-npm "arch" "i386"
+}
+
+# macOS use homebrew but falls back to standalone when brew is unavailable then
+# to npm for unsupported architectures.
+@test "$SCRIPT_NAME: macos arm64 (no brew)" {
+  should-fallback-npm-brew "arm64"
+}
+@test "$SCRIPT_NAME: macos amd64 (no brew)" {
+  BREW_PATH= OS=macos ARCH=amd64 run "$SCRIPT" --dry-run
+  [ "$status" -eq 0 ]
+  [ "${lines[1]}" = "Homebrew not installed." ]
+  [ "${lines[2]}" = "Falling back to standalone installation." ]
+  [ "${lines[3]}" = "Installing v$VERSION of the amd64 release from GitHub." ]
+  [[ "${lines[-5]}" = "Standalone release has been installed"* ]]
+}
+@test "$SCRIPT_NAME: macos i386 (no brew)" {
+  should-fallback-npm-brew "i386"
+}
+
+@test "$SCRIPT_NAME: macos arm64 (brew)" {
+  should-use-brew "arm64"
+}
+@test "$SCRIPT_NAME: macos amd64 (brew)" {
+  should-use-brew "amd64"
+}
+@test "$SCRIPT_NAME: macos i386 (brew)" {
+  should-use-brew "i386"
+}
+
+# Force standalone.
+@test "$SCRIPT_NAME: debian amd64 --method standalone" {
+  should-use-standalone "debian" "amd64" "linux"
+}