docker-php-extension-installer/scripts/test-installcomposer

#!/bin/sh

# Let's set a sane environment
set -o errexit
set -o nounset

WANTED_VERSION="${1:-}"
INSTALLME=@composer
if test -n "$WANTED_VERSION"; then
	INSTALLME="$INSTALLME-$1"
fi

CI=true ./install-php-extensions "$INSTALLME"

INSTALLED_VERSION="$(composer --version | sed -E 's/^.*[Vv]ersion\s*(\S+).*$/\1/')"
if test -z "$WANTED_VERSION"; then
	echo 'Installing the latest version worked'
elif printf '%s' "$WANTED_VERSION" | grep -Eq '^[0-9]+$'; then
	if test "${INSTALLED_VERSION#$WANTED_VERSION.}" = "$INSTALLED_VERSION"; then
		printf 'Installing major version %s DID NOT worked (we installed version %s)\n' "$WANTED_VERSION" "$INSTALLED_VERSION"
		exit 1
	fi
	printf 'Installing major version %s worked (we installed version %s)\n' "$WANTED_VERSION" "$INSTALLED_VERSION"
else
	if test "$INSTALLED_VERSION" != "$WANTED_VERSION"; then
		printf 'Installing specific version %s DID NOT worked (we installed version %s)\n' "$WANTED_VERSION" "$INSTALLED_VERSION"
		exit 1
	fi
	printf 'Installing specific version %s worked\n' "$INSTALLED_VERSION"
fi