docs: Add contributing guide and docs about performance tests (#235)

tests/Dockerfile

@@ -0,0 +1,11 @@
+FROM pre-commit
+
+RUN apt update && \
+    apt install -y \
+        datamash \
+        time && \
+    # Cleanup
+    rm -rf /var/lib/apt/lists/*
+
+WORKDIR /pct
+ENTRYPOINT [ "/pct/tests/hooks_performance_test.sh" ]

tests/hooks_performance_test.sh

@@ -0,0 +1,126 @@
+#!/usr/bin/env bash
+
+TEST_NUM=$1                            # 1000
+TEST_COMMAND=$2                        # 'pre-commit try-repo -a /tmp/159/pre-commit-terraform terraform_tfsec'
+TEST_DIR=$3                            # '/tmp/infrastructure'
+TEST_DESCRIPTION="$TEST_NUM runs '$4'" # '`terraform_tfsec` PR #123:'
+RAW_TEST_RESULTS_FILE_NAME=$5          # terraform_tfsec_pr123
+
+function run_tests {
+  local TEST_NUM=$1
+  local TEST_DIR=$2
+  local TEST_COMMAND
+  IFS=" " read -r -a TEST_COMMAND <<< "$3"
+  local FILE_NAME_TO_SAVE_TEST_RESULTS=$4
+
+  local RESULTS_DIR
+  RESULTS_DIR="$(pwd)/tests/results"
+
+  cd "$TEST_DIR" || { echo "Specified TEST_DIR does not exist" && exit 1; }
+
+  for ((i = 1; i <= TEST_NUM; i++)); do
+    {
+      echo -e "\n\nTest run $i times\n\n"
+      /usr/bin/time --quiet -f '%U user %S system %P cpu %e total' \
+        "${TEST_COMMAND[@]}"
+    } 2>> "$RESULTS_DIR/$FILE_NAME_TO_SAVE_TEST_RESULTS"
+  done
+  # shellcheck disable=2164 # Always exist
+  cd - > /dev/null
+}
+
+function generate_table {
+  local FILE_PATH="tests/results/$1"
+
+  local users_seconds system_seconds cpu total_time
+  users_seconds=$(awk '{ print $1; }' "$FILE_PATH")
+  system_seconds=$(awk '{ print $3; }' "$FILE_PATH")
+  cpu=$(awk '{ gsub("%","",$5); print $5; }' "$FILE_PATH")
+  total_time=$(awk '{ print $7; }' "$FILE_PATH")
+
+  echo "
+| time command   | max    | min    | mean     | median |
+| -------------- | ------ | ------ | -------- | ------ |
+| users seconds  | $(
+    printf %"s\n" $users_seconds | datamash max 1
+  ) | $(
+    printf %"s\n" $users_seconds | datamash min 1
+  ) | $(
+    printf %"s\n" $users_seconds | datamash mean 1
+  ) | $(printf %"s\n" $users_seconds | datamash median 1) |
+| system seconds | $(
+    printf %"s\n" $system_seconds | datamash max 1
+  ) | $(
+    printf %"s\n" $system_seconds | datamash min 1
+  ) | $(
+    printf %"s\n" $system_seconds | datamash mean 1
+  ) | $(printf %"s\n" $system_seconds | datamash median 1) |
+| CPU %          | $(
+    printf %"s\n" $cpu | datamash max 1
+  ) | $(
+    printf %"s\n" $cpu | datamash min 1
+  ) | $(
+    printf %"s\n" $cpu | datamash mean 1
+  ) | $(printf %"s\n" $cpu | datamash median 1) |
+| Total time     | $(
+    printf %"s\n" $total_time | datamash max 1
+  ) | $(
+    printf %"s\n" $total_time | datamash min 1
+  ) | $(
+    printf %"s\n" $total_time | datamash mean 1
+  ) | $(printf %"s\n" $total_time | datamash median 1) |
+"
+}
+
+function save_result {
+  local DESCRIPTION=$1
+  local TABLE=$2
+  local TEST_RUN_START_TIME=$3
+  local TEST_RUN_END_TIME=$4
+
+  local FILE_NAME=${5:-"tests_result.md"}
+
+  echo -e "\n$DESCRIPTION" >> "tests/results/$FILE_NAME"
+  echo -e "$TABLE" >> "tests/results/$FILE_NAME"
+  # shellcheck disable=SC2016,SC2128 # Irrelevant
+  echo -e '
+<details><summary>Run details</summary>
+
+* Test Start: '"$TEST_RUN_START_TIME"'
+* Test End: '"$TEST_RUN_END_TIME"'
+
+| Variable name                | Value |
+| ---------------------------- | --- |
+| `TEST_NUM`                   | <code>'"$TEST_NUM"'</code> |
+| `TEST_COMMAND`               | <code>'"$TEST_COMMAND"'</code> |
+| `TEST_DIR`                   | <code>'"$TEST_DIR"'</code> |
+| `TEST_DESCRIPTION`           | <code>'"$TEST_DESCRIPTION"'</code> |
+| `RAW_TEST_RESULTS_FILE_NAME` | <code>'"$RAW_TEST_RESULTS_FILE_NAME"'</code> |
+
+Memory info (`head -n 6 /proc/meminfo`):
+
+```bash
+'"$(head -n 6 /proc/meminfo)"'
+```
+
+CPU info:
+
+```bash
+Real procs: '"$(grep ^cpu\\scores /proc/cpuinfo | uniq | awk '{print $4}')"'
+Virtual (hyper-threading) procs: '"$(grep -c ^processor /proc/cpuinfo)"'
+'"$(tail -n 28 /proc/cpuinfo)"'
+```
+
+</details>
+' >> "tests/results/$FILE_NAME"
+
+}
+
+mkdir -p tests/results
+TEST_RUN_START_TIME=$(date -u)
+# shellcheck disable=SC2128 # Irrelevant
+run_tests "$TEST_NUM" "$TEST_DIR" "$TEST_COMMAND" "$RAW_TEST_RESULTS_FILE_NAME"
+TEST_RUN_END_TIME=$(date -u)
+
+TABLE=$(generate_table "$RAW_TEST_RESULTS_FILE_NAME")
+save_result "$TEST_DESCRIPTION" "$TABLE" "$TEST_RUN_START_TIME" "$TEST_RUN_END_TIME"