Add test which confirms builtins can be extended from

Author: Jake Champion

integration-tests/js-compute/fixtures/extend-from-builtins/extend-from-builtins.ts

@@ -0,0 +1,71 @@
+/// <reference types="@fastly/js-compute" />
+
+const builtins = [
+    TransformStream,
+    // CompressionStream,
+    // Request,
+    // Response,
+    // Dictionary,
+    // Headers,
+    // CacheOverride,
+    // TextEncoder,
+    // TextDecoder,
+    // URL,
+    // URLSearchParams,
+  ]
+  
+  addEventListener("fetch", event => {
+    for (const builtin of builtins) {
+      class customClass extends builtin {
+        constructor() {
+          switch (builtin.name) {
+            case "CacheOverride": {
+              super('none');
+              break;
+            }
+            case "CompressionStream": {
+              super("gzip")
+              break;
+            }
+            case "Dictionary": {
+              super("example")
+              break
+            }
+            case "Request":
+            case "URL": {
+              super("http://example.com")
+              break;
+            }
+            default: {
+              super()
+            }
+          }
+        }
+        shrimp() { return 'shrimp'; }
+      }
+      const instance = new customClass();
+      if (Reflect.getPrototypeOf(instance) !== customClass.prototype) {
+        throw new Error(
+          "Extending from `"+builtin.name+"`: Expected `Reflect.getPrototypeOf(instance) === customClass.prototype` to be `true`, instead found: `false`"
+        );
+      }
+      if ((instance instanceof customClass) !== true) {
+        throw new Error(
+          "Extending from `"+builtin.name+"`: Expected `instance instanceof customClass` to be `true`, instead found: `false`"
+        );
+      }
+      if (Reflect.has(instance, "shrimp") !== true) {
+        throw new Error(
+          "Extending from `"+builtin.name+"`: Expected `Reflect.has(instance, \"shrimp\")` to be `true`, instead found: `false`"
+        );
+      }
+      if (typeof instance.shrimp !== "function") {
+        throw new Error(
+          "Extending from `"+builtin.name+"`: Expected `typeof instance.shrimp` to be `function`, instead found: `" + typeof instance.shrimp + "`"
+        );
+      }
+
+      console.log(`Tests for extending from ${builtin.name} all passed`)
+    }
+    event.respondWith(new Response);
+  });

integration-tests/js-compute/fixtures/extend-from-builtins/fastly.toml

@@ -0,0 +1,9 @@
+# This file describes a Fastly Compute@Edge package. To learn more visit:
+# https://developer.fastly.com/reference/fastly-toml/
+
+authors = [""]
+description = ""
+language = "javascript"
+manifest_version = 2
+name = "extend-from-builtins"
+service_id = ""

integration-tests/js-compute/sdk-test-config.json

@@ -328,6 +328,26 @@
           }
         }
       }
+    },
+
+    "extend-from-builtins" : {
+      "build": "(cd integration-tests/js-compute && npm install && npm run build:test --test=extend-from-builtins) && (cd ./integration-tests/js-compute/fixtures/extend-from-builtins && fastly compute pack --verbose --wasm-binary ./extend-from-builtins.wasm)",
+      "fastly_toml_path": "./integration-tests/js-compute/fixtures/extend-from-builtins/fastly.toml",
+      "wasm_path": "./integration-tests/js-compute/fixtures/extend-from-builtins/extend-from-builtins.wasm",
+      "pkg_path": "./integration-tests/js-compute/fixtures/extend-from-builtins/pkg/extend-from-builtins.tar.gz",
+      "tests": {
+        "GET /": {
+          "environments": ["viceroy"],
+          "downstream_request": {
+            "method": "GET",
+            "pathname": "/"
+          },
+          "downstream_response": {
+            "status": 200,
+            "body": ""
+          }
+        }
+      }
     }
 
   }