fix(elbv2): validate rule priority is a positive number

packages/@aws-cdk/aws-elasticloadbalancingv2/lib/alb/application-listener-rule.ts

@@ -179,6 +179,10 @@ export class ApplicationListenerRule extends cdk.Construct {
       throw new Error(`'${providedActions}' specified together, specify only one`);
     }
 
+    if (props.priority <= 0) {
+      throw new Error('Priority must have value greater than or equal to 1');
+    }
+
     this.listener = props.listener;
 
     const resource = new CfnListenerRule(this, 'Resource', {

packages/@aws-cdk/aws-elasticloadbalancingv2/test/alb/test.listener.ts

@@ -773,6 +773,30 @@ export = {
     test.done();
   },
 
+  'Throws when specifying priority 0'(test: Test) {
+    // GIVEN
+    const stack = new cdk.Stack();
+    const vpc = new ec2.Vpc(stack, 'VPC');
+    const lb = new elbv2.ApplicationLoadBalancer(stack, 'LoadBalancer', {
+      vpc
+    });
+    const listener = lb.addListener('Listener', {
+      port: 80
+    });
+
+    // THEN
+    test.throws(() => new elbv2.ApplicationListenerRule(stack, 'Rule', {
+      listener,
+      priority: 0,
+      pathPattern: '/hello',
+      fixedResponse: {
+        statusCode: '500'
+      }
+    }), Error, 'Priority must have value greater than or equal to 1');
+
+    test.done();
+  },
+
   'Throws when specifying both target groups and redirect reponse'(test: Test) {
     // GIVEN
     const stack = new cdk.Stack();