Make fetch API more standards compliant (#3667)

cli/js/fetch_test.ts

@@ -5,7 +5,8 @@ import {
   assert,
   assertEquals,
   assertStrContains,
-  assertThrows
+  assertThrows,
+  fail
 } from "./test_util.ts";
 
 testPerm({ net: true }, async function fetchConnectionError(): Promise<void> {
@@ -360,3 +361,75 @@ testPerm({ net: true }, async function fetchPostBodyTypedArray():Promise<void> {
   assertEquals(actual, expected);
 });
 */
+
+testPerm({ net: true }, async function fetchWithManualRedirection(): Promise<
+  void
+> {
+  const response = await fetch("http://localhost:4546/", {
+    redirect: "manual"
+  }); // will redirect to http://localhost:4545/
+  assertEquals(response.status, 0);
+  assertEquals(response.statusText, "");
+  assertEquals(response.url, "");
+  assertEquals(response.type, "opaqueredirect");
+  try {
+    await response.text();
+    fail(
+      "Reponse.text() didn't throw on a filtered response without a body (type opaqueredirect)"
+    );
+  } catch (e) {
+    return;
+  }
+});
+
+testPerm({ net: true }, async function fetchWithErrorRedirection(): Promise<
+  void
+> {
+  const response = await fetch("http://localhost:4546/", {
+    redirect: "error"
+  }); // will redirect to http://localhost:4545/
+  assertEquals(response.status, 0);
+  assertEquals(response.statusText, "");
+  assertEquals(response.url, "");
+  assertEquals(response.type, "error");
+  try {
+    await response.text();
+    fail(
+      "Reponse.text() didn't throw on a filtered response without a body (type error)"
+    );
+  } catch (e) {
+    return;
+  }
+});
+
+test(function responseRedirect(): void {
+  const response = new Response(
+    "example.com/beforeredirect",
+    200,
+    "OK",
+    [["This-Should", "Disappear"]],
+    -1,
+    false,
+    null
+  );
+  const redir = response.redirect("example.com/newLocation", 301);
+  assertEquals(redir.status, 301);
+  assertEquals(redir.statusText, "");
+  assertEquals(redir.url, "");
+  assertEquals(redir.headers.get("Location"), "example.com/newLocation");
+  assertEquals(redir.type, "default");
+});
+
+test(function responseConstructionHeaderRemoval(): void {
+  const res = new Response(
+    "example.com",
+    200,
+    "OK",
+    [["Set-Cookie", "mysessionid"]],
+    -1,
+    false,
+    "basic",
+    null
+  );
+  assert(res.headers.get("Set-Cookie") != "mysessionid");
+});