diff --git a/.github/workflows/php.yml b/.github/workflows/php.yml
index 863028d..5f82b6f 100644
--- a/.github/workflows/php.yml
+++ b/.github/workflows/php.yml
@@ -20,7 +20,7 @@ jobs:
       matrix:
         php-version: ['8.3', '8.4', '8.5']
 
-    uses: simplesamlphp/simplesamlphp-test-framework/.github/workflows/reusable_phplinter.yml@v1.11.0
+    uses: simplesamlphp/simplesamlphp-test-framework/.github/workflows/reusable_phplinter.yml@v1.11.1
     with:
       php-version: ${{ matrix.php-version }}
 
@@ -29,7 +29,7 @@ jobs:
     strategy:
       fail-fast: false
 
-    uses: simplesamlphp/simplesamlphp-test-framework/.github/workflows/reusable_linter.yml@v1.11.0
+    uses: simplesamlphp/simplesamlphp-test-framework/.github/workflows/reusable_linter.yml@v1.11.1
     with:
       enable_eslinter: false
       enable_jsonlinter: true
@@ -53,7 +53,7 @@ jobs:
         with:
           php-version: ${{ matrix.php-versions }}
           extensions: ctype, date, dom, fileinfo, filter, hash, json, mbstring, mysql, openssl, pcre,\
-            pdo, pdo_sqlite, posix, soap, spl, xdebug, xml
+            pdo, pdo_sqlite, posix, soap, sodium, spl, xdebug, xml
           tools: composer
           ini-values: error_reporting=E_ALL, pcov.directory=.
           coverage: pcov
@@ -94,7 +94,7 @@ jobs:
 
       - name: Save coverage data
         if: ${{ matrix.php-versions == '8.5' }}
-        uses: actions/upload-artifact@v6
+        uses: actions/upload-artifact@v7
         with:
           name: coverage-data
           path: ${{ github.workspace }}/build
@@ -188,7 +188,7 @@ jobs:
         run: composer install --no-progress --prefer-dist --optimize-autoloader
 
       - name: Check code for hard dependencies missing in composer.json
-        run: composer-require-checker check --config-file tools/composer-require-checker.json composer.json
+        run: composer-require-checker check composer.json
 
       - name: Check code for unused dependencies in composer.json
         run: |
@@ -264,7 +264,7 @@ jobs:
     steps:
       - uses: actions/checkout@v6
 
-      - uses: actions/download-artifact@v7
+      - uses: actions/download-artifact@v8
         with:
           name: coverage-data
           path: ${{ github.workspace }}/build
diff --git a/.php_cs.dist b/.php_cs.dist
index d2968e5..4d8ae39 100644
--- a/.php_cs.dist
+++ b/.php_cs.dist
@@ -2,8 +2,8 @@
 
 $finder = PhpCsFixer\Finder::create()
     ->in([
-        __DIR__ . '/lib',
         __DIR__ . '/metadata/simplesamlphp',
+        __DIR__ . '/src',
         __DIR__ . '/stubs',
         __DIR__ . '/tests',
     ])
diff --git a/1 b/1
new file mode 100644
index 0000000..f13d063
--- /dev/null
+++ b/1
@@ -0,0 +1,35 @@
+pick a6e6d49 Add support for PHPunit 13
+pick e0061f5 Move contents of lib-dir to src-dir
+pick 61fddec Fix CI
+s 08712a5 Fix CI
+
+# Rebase 720ccf7..08712a5 onto 720ccf7 (4 commands)
+#
+# Commands:
+# p, pick <commit> = use commit
+# r, reword <commit> = use commit, but edit the commit message
+# e, edit <commit> = use commit, but stop for amending
+# s, squash <commit> = use commit, but meld into previous commit
+# f, fixup [-C | -c] <commit> = like "squash" but keep only the previous
+#                    commit's log message, unless -C is used, in which case
+#                    keep only this commit's message; -c is same as -C but
+#                    opens the editor
+# x, exec <command> = run command (the rest of the line) using shell
+# b, break = stop here (continue rebase later with 'git rebase --continue')
+# d, drop <commit> = remove commit
+# l, label <label> = label current HEAD with a name
+# t, reset <label> = reset HEAD to a label
+# m, merge [-C <commit> | -c <commit>] <label> [# <oneline>]
+#         create a merge commit using the original merge commit's
+#         message (or the oneline, if no original merge commit was
+#         specified); use -c <commit> to reword the commit message
+# u, update-ref <ref> = track a placeholder for the <ref> to be updated
+#                       to this position in the new commits. The <ref> is
+#                       updated at the end of the rebase
+#
+# These lines can be re-ordered; they are executed from top to bottom.
+#
+# If you remove a line here THAT COMMIT WILL BE LOST.
+#
+# However, if you remove everything, the rebase will be aborted.
+#
diff --git a/codecov.yml b/codecov.yml
new file mode 100644
index 0000000..4affc05
--- /dev/null
+++ b/codecov.yml
@@ -0,0 +1,20 @@
+---
+
+coverage:
+  status:
+    project:
+      default:
+        target: 0%
+        threshold: 2%
+    patch: false
+comment:
+  layout: "diff"
+  behavior: once
+  require_changes: true
+  require_base: false
+  require_head: true
+  branches: null
+github_checks:
+  annotations: false
+ignore:
+  - 'classes/element.registry.php'
diff --git a/composer.json b/composer.json
index a2073af..37eee22 100644
--- a/composer.json
+++ b/composer.json
@@ -12,11 +12,12 @@
     ],
     "autoload": {
         "psr-4": {
-            "SimpleSAML\\TestUtils\\": "lib/"
+            "SimpleSAML\\TestUtils\\": "src/"
         }
     },
     "autoload-dev": {
         "psr-4": {
+            "SimpleSAML\\TestUtils\\": "src/",
             "SimpleSAML\\Test\\TestUtils\\": "tests/src/"
         }
     },
@@ -30,14 +31,13 @@
         "phpstan/phpstan": "^2.1",
         "phpstan/phpstan-mockery": "^2.0",
         "phpstan/phpstan-phpunit": "^2.0",
-        "phpunit/phpunit": "^12.3",
+        "phpunit/phpunit": "^12.3 || ^13.0",
         "psr/log": "^3.0",
+        "simplesamlphp/simplesamlphp": "^2.5@dev",
         "slevomat/coding-standard": "^8.25",
         "squizlabs/php_codesniffer": "^4.0",
-        "symfony/phpunit-bridge": "^8.0"
-    },
-    "require-dev": {
-        "simplesamlphp/simplesamlphp": "^2.5@dev"
+        "symfony/phpunit-bridge": "^8.0",
+        "twig/twig": "~3.23"
     },
     "support": {
         "issues": "https://github.com/simplesamlphp/simplesamlphp-test-framework/issues",
diff --git a/phpcs-simplesamlphp.xml b/phpcs-simplesamlphp.xml
index 97c4617..91d63e3 100644
--- a/phpcs-simplesamlphp.xml
+++ b/phpcs-simplesamlphp.xml
@@ -9,6 +9,9 @@
   <!-- Do not allow unnecessary spaces inside arbitrary parentheses -->
   <rule ref="Generic.WhiteSpace.ArbitraryParenthesesSpacing" />
 
+  <!-- Complain about unresolved merge conflicts -->
+  <rule ref="Generic.VersionControl.GitMergeConflict" />
+
   <config name="installed_paths" value="vendor/slevomat/coding-standard"/>
 
   <!-- Use fully qualified class names in annotations and PHPdoc -->
diff --git a/phpcs.xml b/phpcs.xml
index c2aa8fb..6c0268e 100644
--- a/phpcs.xml
+++ b/phpcs.xml
@@ -6,7 +6,6 @@
     <rule ref="PSR12"/>
     <rule ref="phpcs-simplesamlphp.xml"/>
 
-    <file>lib</file>
     <file>metadata/simplesamlphp</file>
     <file>src</file>
 
diff --git a/phpunit.xml b/phpunit.xml
index 6971499..8da00da 100644
--- a/phpunit.xml
+++ b/phpunit.xml
@@ -15,7 +15,6 @@
   <logging/>
   <source>
     <include>
-      <directory suffix=".php">./lib</directory>
       <directory suffix=".php">./src</directory>
     </include>
   </source>
diff --git a/lib/ArrayLogger.php b/src/ArrayLogger.php
similarity index 71%
rename from lib/ArrayLogger.php
rename to src/ArrayLogger.php
index 40e2f6c..421df60 100644
--- a/lib/ArrayLogger.php
+++ b/src/ArrayLogger.php
@@ -7,12 +7,14 @@
 use SimpleSAML\Configuration;
 use SimpleSAML\Logger\LoggingHandlerInterface;
 
+use function array_merge;
+
 /**
  */
 class ArrayLogger implements LoggingHandlerInterface
 {
     /**
-     * @var array List of log entries by level
+     * @var array<int, array<string>> List of log entries by level
      */
     public array $logs = [];
 
@@ -24,9 +26,9 @@ public function __construct(Configuration $config)
     }
 
 
-    public function log(int $level, string $string): void
+    public function log(int $level, string $str): void
     {
-        $this->logs[$level][] = $string;
+        $this->logs[$level] = array_merge($this->logs[$level], [$str]);
     }
 
 
diff --git a/lib/BuiltInServer.php b/src/BuiltInServer.php
similarity index 94%
rename from lib/BuiltInServer.php
rename to src/BuiltInServer.php
index ed3a2ce..ed66414 100644
--- a/lib/BuiltInServer.php
+++ b/src/BuiltInServer.php
@@ -206,10 +206,10 @@ public function setRouter(string $router): void
      * This function performs an HTTP GET request to the built-in server.
      *
      * @param string $query The query to perform.
-     * @param array $parameters An array (can be empty) with parameters for the requested URI.
-     * @param array $curlopts An array (can be empty) with options for cURL.
+     * @param array<mixed> $parameters An array (can be empty) with parameters for the requested URI.
+     * @param array<mixed> $curlopts An array (can be empty) with options for cURL.
      *
-     * @return array The response obtained from the built-in server.
+     * @return array<mixed> The response obtained from the built-in server.
      */
     public function get(string $query, array $parameters, array $curlopts = []): array
     {
@@ -218,12 +218,12 @@ public function get(string $query, array $parameters, array $curlopts = []): arr
         $url .= (!empty($parameters)) ? '?' . http_build_query($parameters) : '';
         curl_setopt_array($ch, [
             CURLOPT_URL => $url,
-            CURLOPT_RETURNTRANSFER => 1,
-            CURLOPT_HEADER => 1,
+            CURLOPT_RETURNTRANSFER => true,
+            CURLOPT_HEADER => true,
         ]);
         curl_setopt_array($ch, $curlopts);
 
-        /** @var mixed $resp */
+        /** @var string|bool $resp */
         $resp = curl_exec($ch);
         $code = curl_getinfo($ch, CURLINFO_HTTP_CODE);
         list($header, $body) = explode("\r\n\r\n", $resp, 2);
diff --git a/lib/ClearStateTestCase.php b/src/ClearStateTestCase.php
similarity index 100%
rename from lib/ClearStateTestCase.php
rename to src/ClearStateTestCase.php
diff --git a/lib/InMemoryStore.php b/src/InMemoryStore.php
similarity index 98%
rename from lib/InMemoryStore.php
rename to src/InMemoryStore.php
index 5c0a41e..719210c 100644
--- a/lib/InMemoryStore.php
+++ b/src/InMemoryStore.php
@@ -16,6 +16,7 @@
  */
 class InMemoryStore implements ClearableState, StoreInterface
 {
+    /** @var array<mixed> */
     private static array $store = [];
 
 
diff --git a/lib/ReduceSpillOverTest.php b/src/ReduceSpillOverTest.php
similarity index 100%
rename from lib/ReduceSpillOverTest.php
rename to src/ReduceSpillOverTest.php
diff --git a/lib/SigningTestCase.php b/src/SigningTestCase.php
similarity index 97%
rename from lib/SigningTestCase.php
rename to src/SigningTestCase.php
index 620ef4d..b6acf0d 100644
--- a/lib/SigningTestCase.php
+++ b/src/SigningTestCase.php
@@ -44,20 +44,7 @@ class SigningTestCase extends TestCase
 
 
     /**
-     * Constructor
-     */
-    public function __construct()
-    {
-        $this->root_directory = dirname(dirname(__FILE__));
-        $base = $this->root_directory . DIRECTORY_SEPARATOR . $this->cert_directory;
-        $this->ca_private_key = file_get_contents($base . DIRECTORY_SEPARATOR . $this->ca_private_key_file);
-        $this->ca_certificate = file_get_contents($base . DIRECTORY_SEPARATOR . $this->ca_certificate_file);
-        $this->good_private_key = file_get_contents($base . DIRECTORY_SEPARATOR . $this->good_private_key_file);
-        $this->good_certificate = file_get_contents($base . DIRECTORY_SEPARATOR . $this->good_certificate_file);
-    }
-
-
-    /**
+     * @return array<mixed>
      */
     public function getCertDirContent(): array
     {
@@ -74,6 +61,13 @@ public function getCertDirContent(): array
      */
     public function setUp(): void
     {
+        $this->root_directory = dirname(dirname(__FILE__));
+        $base = $this->root_directory . DIRECTORY_SEPARATOR . $this->cert_directory;
+        $this->ca_private_key = file_get_contents($base . DIRECTORY_SEPARATOR . $this->ca_private_key_file);
+        $this->ca_certificate = file_get_contents($base . DIRECTORY_SEPARATOR . $this->ca_certificate_file);
+        $this->good_private_key = file_get_contents($base . DIRECTORY_SEPARATOR . $this->good_private_key_file);
+        $this->good_certificate = file_get_contents($base . DIRECTORY_SEPARATOR . $this->good_certificate_file);
+
         $this->config = Configuration::loadFromArray([
             'certdir' => $this->cert_directory,
         ], '[ARRAY]', 'simplesaml');
diff --git a/lib/SimpleTestLogger.php b/src/SimpleTestLogger.php
similarity index 80%
rename from lib/SimpleTestLogger.php
rename to src/SimpleTestLogger.php
index 6e5a429..3135e89 100644
--- a/lib/SimpleTestLogger.php
+++ b/src/SimpleTestLogger.php
@@ -18,6 +18,7 @@
 final class SimpleTestLogger extends AbstractLogger
 {
     /**
+     * @var array<string>
      */
     private array $messages = [];
 
@@ -41,10 +42,12 @@ public function log($level, string|Stringable $message, array $context = []): vo
      * Get all the messages logged at the specified level
      *
      * @param mixed $level
+     * @return array<mixed> $level
      */
     public function getMessagesForLevel($level): array
     {
-        return array_filter($this->messages, function (string $message) use ($level) {
+        // @phpstan-ignore argument.type
+        return array_filter($this->messages, function (array $message) use ($level) {
             return $message['level'] === $level;
         });
     }
@@ -57,7 +60,8 @@ public function getMessagesForLevel($level): array
      */
     public function hasMessage(string|Stringable $messageToFind): bool
     {
-        $count = array_filter($this->messages, function ($message) use ($messageToFind) {
+        // @phpstan-ignore argument.type
+        $count = array_filter($this->messages, function (array $message) use ($messageToFind) {
             return $message['message'] === $messageToFind;
         });
 
diff --git a/lib/StateClearer.php b/src/StateClearer.php
similarity index 96%
rename from lib/StateClearer.php
rename to src/StateClearer.php
index 7d5263f..d183b01 100644
--- a/lib/StateClearer.php
+++ b/src/StateClearer.php
@@ -16,11 +16,15 @@ class StateClearer
 {
     /**
      * Global state to restore between test runs
+     *
+     * @var array<mixed>
      */
     private array $backups = [];
 
     /**
      * Class that implement \SimpleSAML\Utils\ClearableState and should have clearInternalState called between tests
+     *
+     * @var array<mixed>
      */
     private array $clearableState = [
         Configuration::class,
@@ -31,6 +35,8 @@ class StateClearer
 
     /**
      * Environmental variables to unset
+     *
+     * @var array<mixed>
      */
     private array $vars_to_unset = ['SIMPLESAMLPHP_CONFIG_DIR'];
 
diff --git a/tools/composer-require-checker.json b/tools/composer-require-checker.json
index f75b225..eed71aa 100644
--- a/tools/composer-require-checker.json
+++ b/tools/composer-require-checker.json
@@ -1,13 +1,4 @@
 {
   "symbol-whitelist": [
-    "SimpleSAML\\Configuration",
-    "SimpleSAML\\Error\\ConfigurationError",
-    "SimpleSAML\\Logger\\LoggingHandlerInterface",
-    "SimpleSAML\\Metadata\\MetaDataStorageHandler",
-    "SimpleSAML\\Session",
-    "SimpleSAML\\Store\\StoreFactory",
-    "SimpleSAML\\Store\\StoreInterface",
-    "SimpleSAML\\Utils\\ClearableState",
-    "SimpleSAML\\Utils\\System"
   ]
 }