[reverse-string] Check for the use of a rev command

bin/run-tests-in-docker.sh

@@ -21,7 +21,7 @@ docker run \
     --network none \
     --read-only \
     --mount type=bind,src="${PWD}/tests",dst=/opt/analyzer/tests \
-    --mount type=tmpfs,dst=/tmp \
+    --mount type=volume,dst=/tmp \
     --workdir /opt/analyzer \
     --entrypoint /opt/analyzer/bin/run-tests.sh \
     exercism/bash-analyzer

lib/reverse-string/analysis.bash

@@ -0,0 +1,90 @@
+#!/usr/bin/env bash
+
+# Check for using the `rev` executable.
+uses_rev() {
+    local tmp output
+
+    tmp=$(mktemp -d)
+    trap "rm -r ${tmp}" EXIT
+    {
+        echo '#!/usr/bin/env bash'
+        echo 'echo USES_REV'
+    } > "${tmp}/rev"
+    chmod 755 "${tmp}/rev"
+
+    output=$(
+        PATH="${tmp}:${PATH}"
+        bash "${in_dir}/reverse_string.sh" "input"
+    )
+
+    [[ $output = *USES_REV* ]] && echo '{"comment": "bash.reverse-string.uses_rev", "type": "actionable"}'
+}
+
+# Other check functions can go here:
+# ...
+
+
+# ------------------------------------------------------------
+# Merge results into analysis.json generated by the shellcheck analysis.
+
+comments_array_as_json() {
+    jq -n --jsonargs '{comments: $ARGS.positional}' "$@"
+}
+
+write_json() {
+    local -i shellcheck_comments
+    local temp
+
+    # How many shellcheck comments were found?
+    shellcheck_comments=$(jq '.comments | length' "$out_dir/analysis.json")
+
+    case "$shellcheck_comments,${#general_comments[@]}" in
+        0,0)
+            jq -n '{
+                summary: "Congrats! No suggestions",
+                comments: []
+            }' > "$out_dir/analysis.json"
+            ;;
+        0,*)
+            comments_array_as_json "${general_comments[@]}" \
+            | jq '.summary = "Some comments"' \
+            > "$out_dir"/analysis.json
+            ;;
+        *,0)
+            # no need to alter analysis.json
+            : ;;
+        *,*)
+            temp=$(mktemp)
+
+            # grab the summary from the shellcheck analysis
+            summary=$(jq -r .summary "$out_dir/analysis.json")
+
+            # Thanks to https://stackoverflow.com/a/36218044/7552
+            jq --arg sum "$summary" --slurp '{
+                summary: $sum,
+                comments: (reduce .[] as $item ([]; . + $item.comments))
+            }' \
+                "$out_dir/analysis.json" \
+                <(comments_array_as_json "${general_comments[@]}") \
+                > "$temp" && mv "$temp" "$out_dir/analysis.json"
+            ;;
+    esac
+}
+
+# ------------------------------------------------------------
+analyze() {
+    local in_dir=$1 out_dir=$2 snake_slug=$3
+    local filename="$in_dir/${snake_slug}.sh"
+    local general_comments=()
+    local IFS=,
+
+    json=$(uses_rev)
+    [[ -n $json ]] && general_comments+=("$json")
+
+    # other checks can go here to add to the "general_comments" array
+    # ....
+
+    write_json
+}
+
+analyze "$@"

tests/reverse-string/expected_analysis.json

@@ -0,0 +1,9 @@
+{
+  "comments": [
+    {
+      "comment": "bash.reverse-string.uses_rev",
+      "type": "actionable"
+    }
+  ],
+  "summary": "Some comments"
+}

tests/reverse-string/reverse_string.sh

@@ -0,0 +1 @@
+rev <<< "$1"