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Diffstat (limited to 'lib/path/tests/prop.sh')
| -rwxr-xr-x | lib/path/tests/prop.sh | 179 |
1 files changed, 179 insertions, 0 deletions
diff --git a/lib/path/tests/prop.sh b/lib/path/tests/prop.sh new file mode 100755 index 000000000000..c956e55bbfa0 --- /dev/null +++ b/lib/path/tests/prop.sh @@ -0,0 +1,179 @@ +#!/usr/bin/env bash + +# Property tests for the `lib.path` library +# +# It generates random path-like strings and runs the functions on +# them, checking that the expected laws of the functions hold + +set -euo pipefail +shopt -s inherit_errexit + +# https://stackoverflow.com/a/246128 +SCRIPT_DIR=$( cd -- "$( dirname -- "${BASH_SOURCE[0]}" )" &> /dev/null && pwd ) + +if test -z "${TEST_LIB:-}"; then + TEST_LIB=$SCRIPT_DIR/../.. +fi + +tmp="$(mktemp -d)" +clean_up() { + rm -rf "$tmp" +} +trap clean_up EXIT +mkdir -p "$tmp/work" +cd "$tmp/work" + +# Defaulting to a random seed but the first argument can override this +seed=${1:-$RANDOM} +echo >&2 "Using seed $seed, use \`lib/path/tests/prop.sh $seed\` to reproduce this result" + +# The number of random paths to generate. This specific number was chosen to +# be fast enough while still generating enough variety to detect bugs. +count=500 + +debug=0 +# debug=1 # print some extra info +# debug=2 # print generated values + +# Fine tuning parameters to balance the number of generated invalid paths +# to the variance in generated paths. +extradotweight=64 # Larger value: more dots +extraslashweight=64 # Larger value: more slashes +extranullweight=16 # Larger value: shorter strings + +die() { + echo >&2 "test case failed: " "$@" + exit 1 +} + +if [[ "$debug" -ge 1 ]]; then + echo >&2 "Generating $count random path-like strings" +fi + +# Read stream of null-terminated strings entry-by-entry into bash, +# write it to a file and the `strings` array. +declare -a strings=() +mkdir -p "$tmp/strings" +while IFS= read -r -d $'\0' str; do + echo -n "$str" > "$tmp/strings/${#strings[@]}" + strings+=("$str") +done < <(awk \ + -f "$SCRIPT_DIR"/generate.awk \ + -v seed="$seed" \ + -v count="$count" \ + -v extradotweight="$extradotweight" \ + -v extraslashweight="$extraslashweight" \ + -v extranullweight="$extranullweight") + +if [[ "$debug" -ge 1 ]]; then + echo >&2 "Trying to normalise the generated path-like strings with Nix" +fi + +# Precalculate all normalisations with a single Nix call. Calling Nix for each +# string individually would take way too long +nix-instantiate --eval --strict --json \ + --argstr libpath "$TEST_LIB" \ + --argstr dir "$tmp/strings" \ + "$SCRIPT_DIR"/prop.nix \ + >"$tmp/result.json" + +# Uses some jq magic to turn the resulting attribute set into an associative +# bash array assignment +declare -A normalised_result="($(jq ' + to_entries + | map("[\(.key | @sh)]=\(.value | @sh)") + | join(" \n")' -r < "$tmp/result.json"))" + +# Looks up a normalisation result for a string +# Checks that the normalisation is only failing iff it's an invalid subpath +# For valid subpaths, returns 0 and prints the normalisation result +# For invalid subpaths, returns 1 +normalise() { + local str=$1 + # Uses the same check for validity as in the library implementation + if [[ "$str" == "" || "$str" == /* || "$str" =~ ^(.*/)?\.\.(/.*)?$ ]]; then + valid= + else + valid=1 + fi + + normalised=${normalised_result[$str]} + # An empty string indicates failure, this is encoded in ./prop.nix + if [[ -n "$normalised" ]]; then + if [[ -n "$valid" ]]; then + echo "$normalised" + else + die "For invalid subpath \"$str\", lib.path.subpath.normalise returned this result: \"$normalised\"" + fi + else + if [[ -n "$valid" ]]; then + die "For valid subpath \"$str\", lib.path.subpath.normalise failed" + else + if [[ "$debug" -ge 2 ]]; then + echo >&2 "String \"$str\" is not a valid subpath" + fi + # Invalid and it correctly failed, we let the caller continue if they catch the exit code + return 1 + fi + fi +} + +# Intermediate result populated by test_idempotency_realpath +# and used in test_normalise_uniqueness +# +# Contains a mapping from a normalised subpath to the realpath result it represents +declare -A norm_to_real + +test_idempotency_realpath() { + if [[ "$debug" -ge 1 ]]; then + echo >&2 "Checking idempotency of each result and making sure the realpath result isn't changed" + fi + + # Count invalid subpaths to display stats + invalid=0 + for str in "${strings[@]}"; do + if ! result=$(normalise "$str"); then + ((invalid++)) || true + continue + fi + + # Check the law that it doesn't change the result of a realpath + mkdir -p -- "$str" "$result" + real_orig=$(realpath -- "$str") + real_norm=$(realpath -- "$result") + + if [[ "$real_orig" != "$real_norm" ]]; then + die "realpath of the original string \"$str\" (\"$real_orig\") is not the same as realpath of the normalisation \"$result\" (\"$real_norm\")" + fi + + if [[ "$debug" -ge 2 ]]; then + echo >&2 "String \"$str\" gets normalised to \"$result\" and file path \"$real_orig\"" + fi + norm_to_real["$result"]="$real_orig" + done + if [[ "$debug" -ge 1 ]]; then + echo >&2 "$(bc <<< "scale=1; 100 / $count * $invalid")% of the total $count generated strings were invalid subpath strings, and were therefore ignored" + fi +} + +test_normalise_uniqueness() { + if [[ "$debug" -ge 1 ]]; then + echo >&2 "Checking for the uniqueness law" + fi + + for norm_p in "${!norm_to_real[@]}"; do + real_p=${norm_to_real["$norm_p"]} + for norm_q in "${!norm_to_real[@]}"; do + real_q=${norm_to_real["$norm_q"]} + # Checks normalisation uniqueness law for each pair of values + if [[ "$norm_p" != "$norm_q" && "$real_p" == "$real_q" ]]; then + die "Normalisations \"$norm_p\" and \"$norm_q\" are different, but the realpath of them is the same: \"$real_p\"" + fi + done + done +} + +test_idempotency_realpath +test_normalise_uniqueness + +echo >&2 tests ok |