Fix colorized jest output (#1601)

* Revert "Update ava.config.js (#1582)"

This reverts commit aff9bb9.

* Try a different trick to get expect() emitting colorized diffs without permanent process.env changes

* amending

ava.config.js

@@ -3,8 +3,12 @@ export default {
   failWithoutAssertions: false,
   environmentVariables: {
     ts_node_install_lock: `id-${Math.floor(Math.random() * 10e9)}`,
-    // Force jest expect() errors to generate colorized strings, makes output more readable
+    // Force jest expect() errors to generate colorized strings, makes output more readable.
+    // Delete the env var within ava processes via `require` option below.
+    // This avoids passing it to spawned processes under test, which would negatively affect
+    // their behavior.
     FORCE_COLOR: '3',
   },
+  require: ['./src/test/remove-env-var-force-color.js'],
   timeout: '300s',
 };

src/test/exec-helpers.ts

@@ -1,6 +1,6 @@
 import type { ChildProcess, ExecException, ExecOptions } from 'child_process';
 import { exec as childProcessExec } from 'child_process';
-import * as expect from 'expect';
+import { expect } from './testlib';
 
 export type ExecReturn = Promise<ExecResult> & { child: ChildProcess };
 export interface ExecResult {

src/test/helpers.ts

@@ -14,7 +14,6 @@ import type * as tsNodeTypes from '../index';
 import type _createRequire from 'create-require';
 import { has, once } from 'lodash';
 import semver = require('semver');
-import * as expect from 'expect';
 const createRequire: typeof _createRequire = require('create-require');
 export { tsNodeTypes };
 

src/test/remove-env-var-force-color.js

@@ -0,0 +1 @@
+delete process.env.FORCE_COLOR;

src/test/repl/repl-environment.spec.ts

@@ -3,8 +3,7 @@
  * globals, __filename, builtin module accessors.
  */
 
-import { test as _test } from '../testlib';
-import * as expect from 'expect';
+import { test as _test, expect } from '../testlib';
 import * as promisify from 'util.promisify';
 import * as getStream from 'get-stream';
 import {

src/test/repl/repl.spec.ts

@@ -1,6 +1,6 @@
+import { _test, expect } from '../testlib';
 import { ts } from '../helpers';
 import semver = require('semver');
-import * as expect from 'expect';
 import {
   CMD_TS_NODE_WITH_PROJECT_FLAG,
   contextTsNodeUnderTest,
@@ -9,7 +9,6 @@ import {
 } from '../helpers';
 import { createExec, createExecTester } from '../exec-helpers';
 import { upstreamTopLevelAwaitTests } from './node-repl-tla';
-import { _test } from '../testlib';
 import { contextReplHelpers } from './helpers';
 import { promisify } from 'util';
 

src/test/testlib.ts

@@ -11,7 +11,9 @@ import avaTest, {
 } from 'ava';
 import * as assert from 'assert';
 import throat from 'throat';
-export { ExecutionContext };
+import * as expect from 'expect';
+
+export { ExecutionContext, expect };
 
 // NOTE: this limits concurrency within a single process, but AVA launches
 // each .spec file in its own process, so actual concurrency is higher.