Add BATS unit testing to project.

.github/Dockerfile.al2023-test

@@ -1,3 +1,10 @@
 FROM public.ecr.aws/amazonlinux/amazonlinux:2023
 
-RUN dnf -y install make rpm-build openssh-clients
+ARG BATS_VERSION=v1.14.0
+
+RUN dnf -y install git make rpm-build openssh-clients && \
+    git clone --depth 1 --branch "${BATS_VERSION}" \
+        https://github.com/bats-core/bats-core.git /tmp/bats && \
+    /tmp/bats/install.sh /usr/local && \
+    rm -rf /tmp/bats && \
+    dnf clean all

.github/Dockerfile.debian-sid-test

@@ -2,4 +2,4 @@ FROM public.ecr.aws/debian/debian:sid
 
 RUN apt-get update && \
     DEBIAN_FRONTEND=noninteractive apt-get -y dist-upgrade && \
-    DEBIAN_FRONTEND=noninteractive apt-get -y install --no-install-recommends build-essential debhelper git devscripts shellcheck
+    DEBIAN_FRONTEND=noninteractive apt-get -y install --no-install-recommends bats build-essential debhelper git devscripts shellcheck

.github/Dockerfile.debian12-test

@@ -1,3 +1,3 @@
 FROM public.ecr.aws/debian/debian:12
 
-RUN apt-get update && DEBIAN_FRONTEND=noninteractive apt-get -y install --no-install-recommends build-essential debhelper git devscripts shellcheck
+RUN apt-get update && DEBIAN_FRONTEND=noninteractive apt-get -y install --no-install-recommends bats build-essential debhelper git devscripts shellcheck

.github/container-tests-al2023.sh

@@ -1,5 +1,9 @@
 #!/bin/bash
 
+set -euo pipefail
+
+make unit-test
+
 v=$(rpmspec -q --qf "%{version}" amazon-ec2-net-utils.spec)
 make scratch-sources version=${v}
 mv ../amazon-ec2-net-utils-${v}.tar.gz .

.github/workflows/shellcheck.yml

@@ -1,4 +1,4 @@
-name: shellcheck
+name: shellcheck and unit tests
 
 on:
   push:
@@ -15,6 +15,6 @@ jobs:
     steps:
     - uses: actions/checkout@v3
     - name: Install dependencies
-      run: sudo apt-get update && DEBIAN_FRONTEND=noninteractive sudo apt-get -y install shellcheck
-    - name: Run shellcheck
-      run: shellcheck -s bash -S warning bin/*.sh lib/*.sh
+      run: sudo apt-get update && DEBIAN_FRONTEND=noninteractive sudo apt-get -y install bats shellcheck
+    - name: Run checks
+      run: make check

CONTRIBUTING.md

@@ -47,6 +47,20 @@ To send us a pull request, please:
 GitHub provides additional document on [forking a repository](https://help.github.com/articles/fork-a-repo/) and
 [creating a pull request](https://help.github.com/articles/creating-a-pull-request/).
 
+## Running tests
+
+The test suite requires ShellCheck and Bats. Run all checks with:
+
+    make check
+
+The Bats executable can be supplied explicitly when it is not installed in
+`PATH`:
+
+    make unit-test BATS=/path/to/bats
+
+Unit tests use temporary directories and do not write network configuration
+under `/run`.
+
 
 ## Finding contributions to work on
 Looking at the existing issues is a great way to find something to contribute on. As our projects, by default, use the default GitHub issue labels (enhancement/bug/duplicate/help wanted/invalid/question/wontfix), looking at any 'help wanted' issues is a great place to start.

GNUmakefile

@@ -12,10 +12,13 @@ SHARE_DIR=${DESTDIR}/${PREFIX}/share/${pkgname}
 
 SHELLSCRIPTS=$(wildcard bin/*.sh)
 SHELLLIBS=$(wildcard lib/*.sh)
+SHELLTESTS=$(wildcard tests/*.bash tests/*.bats)
 UDEVRULES=$(wildcard udev/*.rules)
 
 DIRS:=${BINDIR} ${UDEVDIR} ${SYSTEMDDIR} ${SYSTEMD_SYSTEM_DIR} ${SYSTEMD_NETWORK_DIR} ${SHARE_DIR}
 
+BATS?=bats
+
 .PHONY: help
 help: ## show help
 	@egrep -h '\s##\s' $(MAKEFILE_LIST) | sort | awk 'BEGIN {FS = ":.*?## "}; {printf "\033[36m%-20s\033[0m %s\n", $$1, $$2}'
@@ -40,12 +43,23 @@ install: ${SHELLSCRIPTS} ${UDEVRULES} ${SHELLLIBS} | ${DIRS} ## Install the soft
 	$(foreach f,$(wildcard systemd/network/*.network),install -m644 $f ${SYSTEMD_NETWORK_DIR};)
 	$(foreach f,$(wildcard systemd/system/*.service systemd/system/*.timer),install -m644 $f ${SYSTEMD_SYSTEM_DIR};)
 
-.PHONY: check
-check: ## Run tests
-	@set -x; for script in ${SHELLSCRIPTS} ${SHELLLIBS}; do \
+.PHONY: lint
+lint: ## Run shellcheck
+	@set -x; for script in ${SHELLSCRIPTS} ${SHELLLIBS} ${SHELLTESTS}; do \
 		shellcheck --severity warning $${script};\
 	done
 
+.PHONY: unit-test
+unit-test: ## Run Bats unit tests
+	@command -v ${BATS} >/dev/null 2>&1 || { \
+		echo "Bats is required to run unit tests. Set BATS=/path/to/bats if it is not in PATH." >&2; \
+		exit 1; \
+	}
+	${BATS} tests
+
+.PHONY: check
+check: lint unit-test ## Run all checks
+
 .PHONY: scratch-rpm
 scratch-rpm: source_version_suffix=$(shell git describe --dirty --tags | sed "s,^v${version},,")
 scratch-rpm: rpm_version_suffix=$(shell git describe --dirty --tags | sed "s,^v${version},,; s,-,.,g")

bin/set-hostname-imds.sh

@@ -16,10 +16,11 @@
 set -eCo pipefail
 
 libdir=${LIBDIR_OVERRIDE:-/usr/share/amazon-ec2-net-utils}
+hostname_file=${EC2_NET_UTILS_HOSTNAME_FILE_OVERRIDE:-/etc/hostname}
 
 . "${libdir}/lib.sh"
 
-if [ -s /etc/hostname ]; then
+if [ -s "$hostname_file" ]; then
     info "Static hostname is already set - not modifying existing hostname"
     exit 0
 fi

bin/setup-policy-routes.sh

@@ -16,10 +16,11 @@
 set -eo pipefail -o noclobber -o nounset
 
 export unitdir lockdir runtimeroot reload_flag
-declare -r runtimeroot="/run/amazon-ec2-net-utils"
+declare -r runtimeroot="${EC2_NET_UTILS_RUNTIME_ROOT_OVERRIDE:-/run/amazon-ec2-net-utils}"
 declare -r lockdir="${runtimeroot}/setup-policy-routes"
-declare -r unitdir="/run/systemd/network"
+declare -r unitdir="${EC2_NET_UTILS_UNIT_DIR_OVERRIDE:-/run/systemd/network}"
 declare -r reload_flag="${runtimeroot}/.policy-routes-reload-networkd"
+declare -r sys_class_net="${EC2_NET_UTILS_SYS_CLASS_NET_OVERRIDE:-/sys/class/net}"
 
 libdir=${LIBDIR_OVERRIDE:-AMAZON_EC2_NET_UTILS_LIBDIR}
 # shellcheck source=../lib/lib.sh
@@ -31,7 +32,7 @@ iface="$1"
 mkdir -p "$runtimeroot"
 
 do_setup() {
-    ether=$(cat /sys/class/net/${iface}/address)
+    ether=$(cat "${sys_class_net}/${iface}/address")
 
     declare -i changes=0
     changes+=$(setup_interface $iface $ether)
@@ -43,15 +44,15 @@ do_setup() {
 case "$2" in
 refresh)
     register_networkd_reloader
-    [ -e "/sys/class/net/${iface}" ] || exit 0
+    [ -e "${sys_class_net}/${iface}" ] || exit 0
     debug "Starting configuration refresh for $iface"
     do_setup
     ;;
 start)
     register_networkd_reloader
     counter=0
     max_wait=6000   # 10 minute timeout to avoid infinite loop if sysfs node never appears
-    while [ ! -e "/sys/class/net/${iface}" ]; do
+    while [ ! -e "${sys_class_net}/${iface}" ]; do
         if ((counter % 1000 == 0)); then
             debug "Waiting for sysfs node to exist for ${iface} (iteration $counter)"
         fi
@@ -78,7 +79,7 @@ remove)
     # https://github.com/amazonlinux/amazon-ec2-net-utils/pull/107/changes/c35c4d504fea196af3aa4a00c84b17fa54657d9e).
     # In addtion, this code also runs during upgrade, only run this when sysfs node is not present.
     # This means that it's an actual detach rather than a restart.
-    if [ -e "/sys/class/net/${iface}" ]; then
+    if [ -e "${sys_class_net}/${iface}" ]; then
         debug "Link ${iface} still present, skipping configuration removal."
         exit 0
     fi

debian/control

@@ -2,7 +2,7 @@ Source: amazon-ec2-net-utils
 Section: net
 Priority: optional
 Maintainer: Noah Meyerhans <nmeyerha@amazon.com>
-Build-Depends: debhelper-compat (= 12), shellcheck
+Build-Depends: bats, debhelper-compat (= 12), shellcheck
 Standards-Version: 4.4.1
 Homepage: https://github.com/amazonlinux/amazon-ec2-net-utils
 #Vcs-Browser: https://salsa.debian.org/debian/amazon-ec2-net-utils

debian/rules

@@ -20,8 +20,10 @@ export PREFIX=/usr
 
 override_dh_auto_build:
 
+override_dh_auto_test:
+	$(MAKE) check
+
 # dh_make generated override targets
 # This is example for Cmake (See https://bugs.debian.org/641051 )
 #override_dh_auto_configure:
 #	dh_auto_configure -- #	-DCMAKE_LIBRARY_PATH=$(DEB_HOST_MULTIARCH)
-

lib/lib.sh

@@ -14,33 +14,33 @@
 # permissions and limitations under the License.
 
 # These should be set by the calling program
-declare ether
-declare unitdir
-declare lockdir
-declare reload_flag
-declare runtimeroot
+declare -g ether
+declare -g unitdir
+declare -g lockdir
+declare -g reload_flag
+declare -g runtimeroot
 
 # Version information - substituted during installation
-declare PACKAGE_VERSION="AMAZON_EC2_NET_UTILS_VERSION"
+declare -g PACKAGE_VERSION="AMAZON_EC2_NET_UTILS_VERSION"
 if [ -z "$PACKAGE_VERSION" ]; then
     PACKAGE_VERSION="unknown"
 fi
-declare -r USER_AGENT="amazon-ec2-net-utils/$PACKAGE_VERSION"
-declare -r imds_endpoints=("http://169.254.169.254/latest" "http://[fd00:ec2::254]/latest")
-declare -r imds_token_path="api/token"
-declare -r syslog_facility="user"
-declare -r syslog_tag="ec2net"
-declare -i -r rule_base=10000
-declare -r default_route="DEFAULT"
+declare -g -r USER_AGENT="amazon-ec2-net-utils/$PACKAGE_VERSION"
+declare -g -a -r imds_endpoints=("http://169.254.169.254/latest" "http://[fd00:ec2::254]/latest")
+declare -g -r imds_token_path="api/token"
+declare -g -r syslog_facility="user"
+declare -g -r syslog_tag="ec2net"
+declare -g -i -r rule_base=10000
+declare -g -r default_route="DEFAULT"
 
 # Systemd installs routes with a metric of 1024 by default.  We
 # override to a lower metric to ensure that our fully configured
 # interfaces are preferred over those in the process of being
 # configured.
-declare -i -r metric_base=512
-declare imds_endpoint=""
-declare imds_token=""
-declare imds_interface=""
+declare -g -i -r metric_base=512
+declare -g imds_endpoint=""
+declare -g imds_token=""
+declare -g imds_interface=""
 
 make_token_request() {
     local ep=${1:-""}

tests/bin.bats

@@ -0,0 +1,89 @@
+#!/usr/bin/env bats
+
+load test_helper
+
+@test "set-hostname-imds sets an empty static hostname from IMDS" {
+    local call_log="${BATS_TEST_TMPDIR}/set-hostname-calls.log"
+    local hostname_file="${BATS_TEST_TMPDIR}/etc/hostname"
+    local mock_libdir="${BATS_TEST_TMPDIR}/set-hostname-lib"
+
+    mkdir -p "$(dirname "$hostname_file")" "$mock_libdir"
+    : > "$hostname_file"
+    cat > "${mock_libdir}/lib.sh" <<'EOF'
+get_token() {
+    printf 'get_token\n' >> "$CALL_LOG"
+}
+get_imds() {
+    printf 'get_imds %s\n' "$*" >> "$CALL_LOG"
+    printf 'ip-10-0-0-5.ec2.internal\n'
+}
+info() {
+    printf 'info %s\n' "$*" >> "$CALL_LOG"
+}
+error() {
+    printf 'error %s\n' "$*" >> "$CALL_LOG"
+}
+hostnamectl() {
+    printf 'hostnamectl %s\n' "$*" >> "$CALL_LOG"
+}
+EOF
+
+    run env \
+        CALL_LOG="$call_log" \
+        EC2_NET_UTILS_HOSTNAME_FILE_OVERRIDE="$hostname_file" \
+        LIBDIR_OVERRIDE="$mock_libdir" \
+        bash "${BATS_TEST_DIRNAME}/../bin/set-hostname-imds.sh"
+
+    [ "$status" -eq 0 ]
+    grep -Fx "get_token" "$call_log"
+    grep -Fx "get_imds local-hostname" "$call_log"
+    grep -Fx \
+        "info Setting hostname to ip-10-0-0-5.ec2.internal retrieved from IMDS" \
+        "$call_log"
+    grep -Fx \
+        "hostnamectl hostname ip-10-0-0-5.ec2.internal" \
+        "$call_log"
+}
+
+@test "setup-policy-routes refresh configures an existing interface" {
+    local call_log="${BATS_TEST_TMPDIR}/policy-route-calls.log"
+    local mock_libdir="${BATS_TEST_TMPDIR}/policy-route-lib"
+    local runtime_root="${BATS_TEST_TMPDIR}/run/amazon-ec2-net-utils"
+    local sys_class_net="${BATS_TEST_TMPDIR}/sys/class/net"
+    local unit_dir="${BATS_TEST_TMPDIR}/run/systemd/network"
+
+    mkdir -p "$mock_libdir" "${sys_class_net}/ens6" "$unit_dir"
+    printf '00:11:22:33:44:55\n' > "${sys_class_net}/ens6/address"
+    cat > "${mock_libdir}/lib.sh" <<'EOF'
+register_networkd_reloader() {
+    printf 'register_networkd_reloader\n' >> "$CALL_LOG"
+}
+debug() {
+    printf 'debug %s\n' "$*" >> "$CALL_LOG"
+}
+error() {
+    printf 'error %s\n' "$*" >> "$CALL_LOG"
+}
+setup_interface() {
+    printf 'setup_interface %s\n' "$*" >> "$CALL_LOG"
+    printf '1\n'
+}
+EOF
+
+    run env \
+        CALL_LOG="$call_log" \
+        LIBDIR_OVERRIDE="$mock_libdir" \
+        EC2_NET_UTILS_RUNTIME_ROOT_OVERRIDE="$runtime_root" \
+        EC2_NET_UTILS_SYS_CLASS_NET_OVERRIDE="$sys_class_net" \
+        EC2_NET_UTILS_UNIT_DIR_OVERRIDE="$unit_dir" \
+        bash "${BATS_TEST_DIRNAME}/../bin/setup-policy-routes.sh" \
+        "ens6" "refresh"
+
+    [ "$status" -eq 0 ]
+    grep -Fx "register_networkd_reloader" "$call_log"
+    grep -Fx "debug Starting configuration refresh for ens6" "$call_log"
+    grep -Fx \
+        "setup_interface ens6 00:11:22:33:44:55" \
+        "$call_log"
+    [ -e "${runtime_root}/.policy-routes-reload-networkd" ]
+}