fix(apigatewayv2): http api - disallow empty string as domain name (#…

…16044)

Currently, empty strings are allowed for custom domain name values despite other tools such as the AWS CLI not allowing empty string values. This effort brings the `DomainName` construct up to date with other tooling.

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*By submitting this pull request, I confirm that my contribution is made under the terms of the Apache-2.0 license*

packages/@aws-cdk/aws-apigatewayv2/lib/common/domain-name.ts

@@ -84,6 +84,10 @@ export class DomainName extends Resource implements IDomainName {
   constructor(scope: Construct, id: string, props: DomainNameProps) {
     super(scope, id);
 
+    if (props.domainName === '') {
+      throw new Error('empty string for domainName not allowed');
+    }
+
     const domainNameProps: CfnDomainNameProps = {
       domainName: props.domainName,
       domainNameConfigurations: [

packages/@aws-cdk/aws-apigatewayv2/test/http/domain-name.test.ts

@@ -29,6 +29,22 @@ describe('DomainName', () => {
     });
   });
 
+  test('throws when domainName is empty string', () => {
+    // GIVEN
+    const stack = new Stack();
+
+    // WHEN
+    const t = () => {
+      new DomainName(stack, 'DomainName', {
+        domainName: '',
+        certificate: Certificate.fromCertificateArn(stack, 'cert', certArn),
+      });
+    };
+
+    // THEN
+    expect(t).toThrow(/empty string for domainName not allowed/);
+  });
+
   test('import domain name correctly', () => {
     // GIVEN
     const stack = new Stack();