fix(ec2): add missing entry for XLARGE3 (#14750)

----

*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-ec2/lib/instance-types.ts

@@ -527,6 +527,11 @@ export enum InstanceSize {
    */
   XLARGE2 = '2xlarge',
 
+  /**
+   * Instance size XLARGE3 (3xlarge)
+   */
+  XLARGE3 = '3xlarge',
+
   /**
    * Instance size XLARGE4 (4xlarge)
    */

packages/@aws-cdk/aws-ec2/test/instance.test.ts

@@ -21,17 +21,30 @@ beforeEach(() => {
 
 nodeunitShim({
   'instance is created correctly'(test: Test) {
-    // WHEN
-    new Instance(stack, 'Instance', {
-      vpc,
-      machineImage: new AmazonLinuxImage(),
-      instanceType: InstanceType.of(InstanceClass.BURSTABLE4_GRAVITON, InstanceSize.LARGE),
-    });
+    // GIVEN
+    const sampleInstances = [{
+      instanceClass: InstanceClass.BURSTABLE4_GRAVITON,
+      instanceSize: InstanceSize.LARGE,
+      instanceType: 't4g.large',
+    }, {
+      instanceClass: InstanceClass.HIGH_COMPUTE_MEMORY1,
+      instanceSize: InstanceSize.XLARGE3,
+      instanceType: 'z1d.3xlarge',
+    }];
 
-    // THEN
-    cdkExpect(stack).to(haveResource('AWS::EC2::Instance', {
-      InstanceType: 't4g.large',
-    }));
+    for (const [i, sampleInstance] of sampleInstances.entries()) {
+      // WHEN
+      new Instance(stack, `Instance${i}`, {
+        vpc,
+        machineImage: new AmazonLinuxImage(),
+        instanceType: InstanceType.of(sampleInstance.instanceClass, sampleInstance.instanceSize),
+      });
+
+      // THEN
+      cdkExpect(stack).to(haveResource('AWS::EC2::Instance', {
+        InstanceType: sampleInstance.instanceType,
+      }));
+    }
 
     test.done();
   },