diff --git a/test/_global/renv-cache-jq-unit-test.sh b/test/_global/renv-cache-jq-unit-test.sh
new file mode 100755
index 0000000..45b6541
--- /dev/null
+++ b/test/_global/renv-cache-jq-unit-test.sh
@@ -0,0 +1,70 @@
+#!/bin/bash
+set -e
+
+# Load the devcontainer test library IF running in the container
+source dev-container-features-test-lib
+
+echo "🧪 Testing ensure_jq with mocked package managers..."
+
+sed -n '/ensure_jq() {/,/^}/p' /usr/local/bin/renv-cache-renv-restore-build > /tmp/ensure_jq.sh
+
+test_apt_get() {
+  (
+    command() { if [ "$1" = "-v" ] && [ "$2" = "jq" ]; then return 1; elif [ "$1" = "-v" ] && [ "$2" = "apt-get" ]; then return 0; else return 1; fi; }
+    export JQ_INSTALLED=0
+    apt-get() { if [ "$1" = "install" ]; then export JQ_INSTALLED=1; fi; return 0; }
+    rm() { return 0; }
+
+    source /tmp/ensure_jq.sh
+    ensure_jq >/dev/null 2>&1
+
+    [ "$JQ_INSTALLED" = "1" ]
+  )
+}
+
+test_apk() {
+  (
+    command() { if [ "$1" = "-v" ] && [ "$2" = "jq" ]; then return 1; elif [ "$1" = "-v" ] && [ "$2" = "apk" ]; then return 0; else return 1; fi; }
+    export JQ_INSTALLED=0
+    apk() { if [ "$1" = "add" ]; then export JQ_INSTALLED=1; fi; return 0; }
+
+    source /tmp/ensure_jq.sh
+    ensure_jq >/dev/null 2>&1
+
+    [ "$JQ_INSTALLED" = "1" ]
+  )
+}
+
+test_dnf() {
+  (
+    command() { if [ "$1" = "-v" ] && [ "$2" = "jq" ]; then return 1; elif [ "$1" = "-v" ] && [ "$2" = "dnf" ]; then return 0; else return 1; fi; }
+    export JQ_INSTALLED=0
+    dnf() { if [ "$1" = "install" ]; then export JQ_INSTALLED=1; fi; return 0; }
+
+    source /tmp/ensure_jq.sh
+    ensure_jq >/dev/null 2>&1
+
+    [ "$JQ_INSTALLED" = "1" ]
+  )
+}
+
+test_yum() {
+  (
+    command() { if [ "$1" = "-v" ] && [ "$2" = "jq" ]; then return 1; elif [ "$1" = "-v" ] && [ "$2" = "yum" ]; then return 0; else return 1; fi; }
+    export JQ_INSTALLED=0
+    yum() { if [ "$1" = "install" ]; then export JQ_INSTALLED=1; fi; return 0; }
+
+    source /tmp/ensure_jq.sh
+    ensure_jq >/dev/null 2>&1
+
+    [ "$JQ_INSTALLED" = "1" ]
+  )
+}
+
+check "apt-get fallback works" test_apt_get
+check "apk fallback works" test_apk
+check "dnf fallback works" test_dnf
+check "yum fallback works" test_yum
+
+rm /tmp/ensure_jq.sh
+reportResults
diff --git a/test/_global/scenarios.json b/test/_global/scenarios.json
index 44544e6..d7eed32 100644
--- a/test/_global/scenarios.json
+++ b/test/_global/scenarios.json
@@ -19,6 +19,14 @@
              }
         }
    },
+   "renv-cache-jq-unit-test": {
+        "image": "mcr.microsoft.com/devcontainers/base:ubuntu",
+        "features": {
+            "renv-cache": {
+                "restore": false
+             }
+        }
+   },
    "renv-cache-restore": {
         "image": "ghcr.io/rocker-org/devcontainer/r-ver:4.4",
         "features": {