setup_file() {
  export FILE_MARKER
  FILE_MARKER=$(mktemp "${BATS_RUN_TMPDIR}/file_marker.XXXXXX")
  if [[ -n "${DISABLE_IN_SETUP_FILE_FUNCTION:-}" ]]; then
    export BATS_NO_PARALLELIZE_WITHIN_FILE=true
    echo "setup_file() sets BATS_NO_PARALLELIZE_WITHIN_FILE=true" >&2
  fi
}

if [[ -n "${DISABLE_OUTSIDE_ALL_FUNCTIONS:-}" ]]; then
  export BATS_NO_PARALLELIZE_WITHIN_FILE=true
  echo "File sets BATS_NO_PARALLELIZE_WITHIN_FILE=true" >&2
fi

teardown_file() {
  rm "$FILE_MARKER"
}

setup() {
  if [[ -n "${DISABLE_IN_SETUP_FUNCTION:-}" ]]; then
    export BATS_NO_PARALLELIZE_WITHIN_FILE=true
    echo "setup() sets BATS_NO_PARALLELIZE_WITHIN_FILE=true" >&3
  fi
  echo "start $BATS_TEST_NAME" >>"$FILE_MARKER"
}

teardown() {
  echo "end $BATS_TEST_NAME" >>"$FILE_MARKER"
}

@test "test 1" {
  if [[ -n "${DISABLE_IN_TEST_FUNCTION:-}" ]]; then
    export BATS_NO_PARALLELIZE_WITHIN_FILE=true
    echo "Test function sets BATS_NO_PARALLELIZE_WITHIN_FILE=true" >&3
  fi
  # stretch the time this test runs to prevent accidental serialization by the scheduler
  # if both tests could run in parallel, this will increase the likelihood of detecting it
  # by delaying this test's teardown past the other's
  sleep 3
}

@test "test 2" {
  run cat "$FILE_MARKER"
  echo "$output"

  # assuming serialized, ordered execution we will always see the first test start and end before this runs
  [[ "${lines[0]}" == "start"* ]]
  OTHER_TEST_NAME="${lines[0]:6}"
  [[ "$OTHER_TEST_NAME" != "$BATS_TEST_NAME" ]]
  [[ "${lines[1]}" == "end $OTHER_TEST_NAME" ]]
  [[ "${lines[2]}" == "start $BATS_TEST_NAME" ]]
}