feat: add maybe_install_packages function

#!/usr/bin/env bash

set -e

# This function installs packages if required.

# If abstracts the underlying the Linux distro by managing several package systems (Debian and Alpine).

# Determines whether the package is present either by checking the presence of the provided package(s).

# Limitations: assumes the package(s) to install have the same name on all distros

  function maybe_install_packages() {

    if command -v apt-get > /dev/null

    then

      # Debian

      if ! dpkg --status "$@" > /dev/null

      then

        apt-get update

        apt-get install --no-install-recommends --yes --quiet "$@"

      fi

    elif command -v apk > /dev/null

    then

      # Alpine

      if ! apk info --installed "$@" > /dev/null

      then

        apk add --no-cache "$@"

      fi

    else

      log_error "... didn't find any supported package manager to install $*"

      exit 1

    fi

  }

#!/usr/bin/env bats

load "${BATS_LIBRARIES_DIR:-$BATS_TEST_DIRNAME/lib}/bats-support/load.bash"

load "${BATS_LIBRARIES_DIR:-$BATS_TEST_DIRNAME/lib}/bats-assert/load.bash"

ROOT_DIR=$(dirname "$BATS_TEST_DIRNAME")

load "$ROOT_DIR/tbc_base.sh"

load "$ROOT_DIR/tbc_maybe_install_packages.sh"

# mocked commands

function dpkg() {

  echo "[mock] dpkg $*"*

  if [[ "$*" == "--status thispkg" ]]

  then

    echo "[mock] dpkg: package thispkg is installed"

  else

    echo "[mock] dpkg: package not installed"

    return 1

  fi

}

function apt-get() {

  echo "[mock] apt-get $*"

}

@test "[deb] package is installed" {

  # GIVEN

  # WHEN

  run maybe_install_packages "thatpkg"

  # THEN

  assert_success

  # assert_equal "$(cmdmock logs dpkg '--status thatpkg' | wc -l)" 0

  assert_line --regexp "\[mock\] apt-get install (.*) thatpkg"

}

@test "[deb] package is not installed" {

  # GIVEN

  # WHEN

  run maybe_install_packages "thispkg"

  # THEN

  assert_success

  # assert_equal "$(cmdmock logs dpkg '--status thispkg' | wc -l)" 0

  refute_output --partial "[mock] apt-get install"

}