diff --git a/tests/test_diff.sh b/tests/test_diff.sh
new file mode 100644
index 0000000..c121d8f
--- /dev/null
+++ b/tests/test_diff.sh
@@ -0,0 +1,87 @@
+#!/bin/bash
+
+# Exit immediately if a command exits with a non-zero status
+set -e
+
+# Define URLs
+GOOG_JSON_URL="https://www.gstatic.com/ipranges/goog.json"
+CLOUD_JSON_URL="https://www.gstatic.com/ipranges/cloud.json"
+PYTHON_SCRIPT_URL="https://raw.githubusercontent.com/GoogleCloudPlatform/networking-tools-python/main/tools/cidr/cidr.py"
+
+# Determine the repository root
+REPO_ROOT="$(git rev-parse --show-toplevel 2>/dev/null)"
+if [ -z "$REPO_ROOT" ]; then
+    echo "Error: This script must be run within a Git repository."
+    exit 1
+fi
+
+# Path to the PHP script
+PHP_SCRIPT_PATH="$REPO_ROOT/google_ip_prefix_diff.php"
+
+if [ ! -f "$PHP_SCRIPT_PATH" ]; then
+    echo "Error: PHP script google_ip_prefix_diff.php not found at $PHP_SCRIPT_PATH."
+    exit 1
+fi
+
+# Create a temporary directory for testing
+TMP_DIR=$(mktemp -d)
+echo "Using temporary directory: $TMP_DIR"
+
+# Cleanup on exit
+cleanup() {
+    rm -rf "$TMP_DIR"
+}
+trap cleanup EXIT
+
+cd "$TMP_DIR"
+
+# Download JSON data
+echo "Downloading goog.json..."
+wget -q "$GOOG_JSON_URL" -O goog.json
+
+echo "Downloading cloud.json..."
+wget -q "$CLOUD_JSON_URL" -O cloud.json
+
+# Download the Python script
+echo "Downloading cidr.py..."
+wget -q "$PYTHON_SCRIPT_URL" -O cidr.py
+chmod +x cidr.py
+
+# Check if Python is installed
+if ! command -v python3 &> /dev/null
+then
+    echo "Error: Python3 could not be found. Please install Python3."
+    exit 1
+fi
+
+# Run the Python script and extract only CIDR lines
+echo "Running Python script..."
+python3 cidr.py goog.json cloud.json | grep -E '^([0-9]{1,3}\.){3}[0-9]{1,3}/[0-9]{1,2}$|^([0-9a-fA-F]{1,4}:){1,7}[0-9a-fA-F]{1,4}/[0-9]{1,3}$|^([0-9a-fA-F]{1,4}:){1,7}:/[0-9]{1,3}$|^::/[0-9]{1,3}$' > python_output.txt
+
+# Check if PHP is installed
+if ! command -v php &> /dev/null
+then
+    echo "Error: PHP could not be found. Please install PHP."
+    exit 1
+fi
+
+# Run the PHP script
+echo "Running PHP script..."
+php "$PHP_SCRIPT_PATH" > php_output.txt
+
+# Sort both outputs
+echo "Sorting outputs..."
+sort python_output.txt > python_sorted.txt
+sort php_output.txt > php_sorted.txt
+
+# Compare the outputs
+echo "Comparing outputs..."
+if diff -u python_sorted.txt php_sorted.txt > diff_output.txt; then
+    echo "Test Passed: PHP and Python outputs match."
+    exit 0
+else
+    echo "Test Failed: Outputs differ."
+    echo "Differences:"
+    cat diff_output.txt
+    exit 1
+fi