refactor(cache-magento): extract key computation into a script (#245)

cache-magento/test.sh

@@ -0,0 +1,39 @@
+#!/usr/bin/env bash
+
+SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+SCRIPT="$SCRIPT_DIR/compute-cache-keys.sh"
+PASS=0
+FAIL=0
+
+assert_eq() {
+  local label="$1" expected="$2" actual="$3"
+  if [ "$expected" = "$actual" ]; then
+    echo "PASS: $label"
+    PASS=$((PASS + 1))
+  else
+    echo "FAIL: $label"
+    echo "  expected: $expected"
+    echo "  actual:   $actual"
+    FAIL=$((FAIL + 1))
+  fi
+}
+
+field() {
+  echo "$1" | grep "^${2}=" | cut -d= -f2-
+}
+
+# Default cache key
+OUT=$(bash "$SCRIPT" "_mageos" "8.3.0" "2.2.6")
+assert_eq "default: download-key" \
+  "composer | v5.8 | _mageos | 2.2.6 | 8.3.0" \
+  "$(field "$OUT" download-key)"
+
+# Custom composer_cache_key
+OUT=$(bash "$SCRIPT" "custom-v2" "8.1.5" "2.4.2")
+assert_eq "custom key: download-key" \
+  "composer | v5.8 | custom-v2 | 2.4.2 | 8.1.5" \
+  "$(field "$OUT" download-key)"
+
+echo ""
+echo "$PASS passed, $FAIL failed"
+[ "$FAIL" -eq 0 ]