Snapshot testing for shunit2

shunit_snapshot.sh

snapshot() {
  mkdir -p snapshots
  local FILE_NAME="$1"
  local EXPECTED="$2"
  local FILE_PATH
  local FILE_CONTENTS

  FILE_PATH="snapshots/$FILE_NAME"

  if [ -f "$FILE_PATH" ]; then
    FILE_CONTENTS=$(cat "$FILE_PATH")
    if [ "$EXPECTED" = "$FILE_CONTENTS" ]; then
      _shunit_assertPass
    else
      if [ "$SNAPSHOT_UPDATE" = "true" ]; then
        echo "$EXPECTED" >"$FILE_PATH"
        fail "Snapshot $FILE_NAME updated, re-run to check"
      else
        failNotEquals "$FILE_NAME" "$FILE_CONTENTS" "$EXPECTED"
      fi
    fi
  else
    echo "$EXPECTED" >"$FILE_PATH"
    fail "Snapshot $FILE_NAME created, re-run to check"
  fi
}