tests: opcache_preload (#2257)

Adds a test to reproduce #2254 and verify `opcache_preload` works as
intended with the changes from
https://github.com/php/frankenphp/pull/2252.

frankenphp_test.go

@@ -22,6 +22,7 @@ import (
 	"net/url"
 	"os"
 	"os/exec"
+	"os/user"
 	"path/filepath"
 	"strconv"
 	"strings"
@@ -1302,3 +1303,30 @@ func TestSessionNoLeakAfterExit_worker(t *testing.T) {
 		realServer:         true,
 	})
 }
+
+func TestOpcachePreload_module(t *testing.T) {
+	testOpcachePreload(t, &testOptions{env: map[string]string{"TEST": "123"}})
+}
+
+func TestOpcachePreload_worker(t *testing.T) {
+	testOpcachePreload(t, &testOptions{workerScript: "preload-check.php", nbWorkers: 1, nbParallelRequests: 1, env: map[string]string{"TEST": "123"}})
+}
+
+func testOpcachePreload(t *testing.T, opts *testOptions) {
+	cwd, _ := os.Getwd()
+	preloadScript := cwd + "/testdata/preload.php"
+
+	u, err := user.Current()
+	require.NoError(t, err)
+
+	opts.phpIni = map[string]string{
+		"opcache.enable":       "1",
+		"opcache.preload":      preloadScript,
+		"opcache.preload_user": u.Username,
+	}
+
+	runTest(t, func(handler func(http.ResponseWriter, *http.Request), _ *httptest.Server, i int) {
+		body, _ := testGet("http://example.com/preload-check.php", handler, t)
+		assert.Equal(t, "I am preloaded", body)
+	}, opts)
+}

testdata/preload-check.php

@@ -0,0 +1,12 @@
+<?php
+
+require_once __DIR__.'/_executor.php';
+
+return function () {
+    if (function_exists('preloaded_function')) {
+        echo preloaded_function();
+    } else {
+        echo 'not preloaded';
+    }    
+};
+

testdata/preload.php

@@ -0,0 +1,8 @@
+<?php
+
+// verify ENV can be accessed during preload
+$_ENV['TEST'] = '123';
+function preloaded_function(): string
+{
+    return 'I am preloaded';
+}