tests: cleanup "node_compat_tests" (#18594)

A few drive-by cleanup while I'm working on the "crypto"
module. It makes it easier and faster to debug the failing
test case.

cli/tests/integration/node_compat_tests.rs

@@ -8,12 +8,6 @@ fn node_compat_tests() {
     .current_dir(util::root_path())
     .arg("test")
     .arg("--unstable")
-    .arg("--import-map")
-    .arg(
-      util::tests_path()
-        .join("node_compat")
-        .join("import_map.json"),
-    )
     .arg("-A")
     .arg(util::tests_path().join("node_compat"))
     .spawn()

cli/tests/node_compat/import_map.json

@@ -1,5 +0,0 @@
-{
-  "imports": {
-    "std/": "../../../test_util/std/"
-  }
-}

cli/tests/node_compat/test.ts

@@ -1,8 +1,22 @@
 // Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
-import { magenta } from "std/fmt/colors.ts";
-import { pooledMap } from "std/async/pool.ts";
-import { dirname, fromFileUrl, join } from "std/path/mod.ts";
-import { fail } from "std/testing/asserts.ts";
+
+/**
+ * This script will run the test files specified in the configuration file.
+ *
+ * Each test file will be run independently (in a separate process as this is
+ * what Node.js is doing) and we wait until it completes. If the process reports
+ * an abnormal code, the test is reported and the test suite will fail
+ * immediately.
+ *
+ * Some tests check for presence of certain `process.exitCode`.
+ * Some tests depends on directories/files created by other tests - they must
+ * all share the same working directory.
+ */
+
+import { magenta } from "../../../test_util/std/fmt/colors.ts";
+import { pooledMap } from "../../../test_util/std/async/pool.ts";
+import { dirname, fromFileUrl, join } from "../../../test_util/std/path/mod.ts";
+import { fail } from "../../../test_util/std/testing/asserts.ts";
 import {
   config,
   getPathsFromTestSuites,
@@ -11,24 +25,14 @@ import {
 
 // If the test case is invoked like
 // deno test -A cli/tests/node_compat/test.ts -- <test-names>
-// Use the test-names as filters
+// Use the <test-names> as filters
 const filters = Deno.args;
 const hasFilters = filters.length > 0;
-
-/**
- * This script will run the test files specified in the configuration file
- *
- * Each test file will be run independently and wait until completion, if an abnormal
- * code for the test is reported, the test suite will fail immediately
- */
-
 const toolsPath = dirname(fromFileUrl(import.meta.url));
-const stdRootUrl = new URL("../../", import.meta.url).href;
 const testPaths = partitionParallelTestPaths(
   getPathsFromTestSuites(config.tests),
 );
 const cwd = new URL(".", import.meta.url);
-const importMap = "import_map.json";
 const windowsIgnorePaths = new Set(
   getPathsFromTestSuites(config.windowsIgnore),
 );
@@ -74,7 +78,7 @@ async function runTest(t: Deno.TestContext, path: string): Promise<void> {
         "--unstable",
         //"--unsafely-ignore-certificate-errors",
         "--v8-flags=" + v8Flags.join(),
-        testCase.endsWith(".mjs") ? "--import-map=" + importMap : "runner.ts",
+        "runner.ts",
         testCase,
       ];
 
@@ -83,7 +87,6 @@ async function runTest(t: Deno.TestContext, path: string): Promise<void> {
       const command = new Deno.Command(Deno.execPath(), {
         args,
         env: {
-          DENO_NODE_COMPAT_URL: stdRootUrl,
           TEST_SERIAL_ID: String(testSerialId++),
         },
         cwd,
@@ -93,15 +96,23 @@ async function runTest(t: Deno.TestContext, path: string): Promise<void> {
       if (code !== 0) {
         // If the test case failed, show the stdout, stderr, and instruction
         // for repeating the single test case.
-        if (stdout.length) console.log(decoder.decode(stdout));
-        console.log(`Error: "${path}" failed`);
-        console.log(
-          "You can repeat only this test with the command:",
-          magenta(
-            `./target/debug/deno test -A --import-map cli/tests/node_compat/import_map.json cli/tests/node_compat/test.ts -- ${path}`,
-          ),
+        if (stdout.length) {
+          console.log(decoder.decode(stdout));
+        }
+        const stderrOutput = decoder.decode(stderr);
+        const repeatCmd = magenta(
+          `./target/debug/deno test -A cli/tests/node_compat/test.ts -- ${path}`,
         );
-        fail(decoder.decode(stderr));
+        const msg = `"${magenta(path)}" failed:
+
+${stderrOutput}
+
+You can repeat only this test with the command:
+  
+  ${repeatCmd}
+`;
+        console.log(msg);
+        fail(msg);
       } else if (hasFilters) {
         // Even if the test case is successful, shows the stdout and stderr
         // when test case filtering is specified.

ext/node/polyfills/README.md

@@ -169,25 +169,6 @@ to pass certain tests. However, avoid doing such manual changes to the test
 files, since that may cover up inconsistencies between the node library and
 actual node behavior.
 
-### Working with child processes ? Use `DENO_NODE_COMPAT_URL`
-
-When working with `child_process` modules, you will have to run tests pulled
-from Node.js. These tests usually spawn deno child processes via the use of
-`process.execPath`. The `deno` executable will use its own embedded version of
-std modules, then you may get the impression your code is not really working as
-it should.
-
-To prevent this, set `DENO_NODE_COMPAT_URL` with the absolute path to your
-`deno_std` repo, ending with a trailing slash:
-
-```
-export DENO_NODE_COMPAT_URL=$PWD/
-# or
-export DENO_NODE_COMPAT_URL=file:///path/to/deno_std/dir/
-```
-
-Then, `deno` will use your local copy of `deno_std` instead of latest version.
-
 ### Best practices
 
 When converting from promise-based to callback-based APIs, the most obvious way