diff --git a/tests/DriversTestCase.php b/tests/DriversTestCase.php
index ea691c18..188316d3 100644
--- a/tests/DriversTestCase.php
+++ b/tests/DriversTestCase.php
@@ -8,7 +8,7 @@
 use PHPUnit\Framework\Attributes\RequiresPhpExtension;
 
 #[RequiresPhpExtension('pdo_sqlite')]
-class DriversTestCase extends CondorcetTestCase
+abstract class DriversTestCase extends CondorcetTestCase
 {
     protected function hashVotesList(Election $elec): string
     {
diff --git a/tests/src/Console/Commands/ConverterCommandTest.php b/tests/src/Console/Commands/ConverterCommandTest.php
index f5bb62d9..41ca156e 100644
--- a/tests/src/Console/Commands/ConverterCommandTest.php
+++ b/tests/src/Console/Commands/ConverterCommandTest.php
@@ -8,21 +8,24 @@
 use Symfony\Component\Console\Tester\CommandTester;
 use Tests\src\Console\ConsoleTestCase;
 
-beforeEach(function () {
+beforeEach(function (): void {
     CondorcetApplication::create();
 
     $this->converterCommand = new CommandTester(CondorcetApplication::$SymfonyConsoleApplication->find('convert'));
 });
-afterEach(function () {
+
+afterEach(function (): void {
     file_exists(self::OUTPUT_FILE) && unlink(self::OUTPUT_FILE);
 });
+
 dataset('conversionsProvider', function () {
     return [
         'fromDebianToCondorcet' => ['--from-debian-format', '--to-condorcet-election-format', ConsoleTestCase::DEBIAN_INPUT_FILE, __DIR__ . '/files/fromDebianExpectedFile.cvotes'],
         'fromDavidHillToCondorcet' => ['--from-david-hill-format', '--to-condorcet-election-format', ConsoleTestCase::DAVIDHILL_INPUT_FILE, __DIR__ . '/files/fromDavidHillExpectedFile.cvotes'],
     ];
 });
-test('successfull conversions', function (string $from, string $to, string $input, string $comparaison) {
+
+test('successfull conversions', function (string $from, string $to, string $input, string $comparaison): void {
     $this->converterCommand->execute(
         [
             $from => true,
@@ -42,7 +45,8 @@
 
     expect(file_get_contents(self::OUTPUT_FILE))->toBe(file_get_contents($comparaison));
 })->with('conversionsProvider');
-test('lacks an option', function () {
+
+test('lacks an option', function (): void {
     $this->expectException(ConsoleInputException::class);
     $this->expectExceptionMessageMatches('/output/');
 
@@ -58,7 +62,8 @@
         ]
     );
 });
-test('lacks an argument', function () {
+
+test('lacks an argument', function (): void {
     $this->expectException(ConsoleInputException::class);
     $this->expectExceptionMessageMatches('/output/');
 
@@ -74,7 +79,8 @@
         ]
     );
 });
-test('wrong input', function () {
+
+test('wrong input', function (): void {
     $this->expectException(CondorcetInternalException::class);
     $this->expectExceptionMessage('The input file does not exist');
 
diff --git a/tests/src/Console/ConsoleTestCase.php b/tests/src/Console/ConsoleTestCase.php
index bdeca4d7..0f59a99e 100644
--- a/tests/src/Console/ConsoleTestCase.php
+++ b/tests/src/Console/ConsoleTestCase.php
@@ -6,7 +6,7 @@
 
 use Tests\CondorcetTestCase;
 
-class ConsoleTestCase extends CondorcetTestCase
+abstract class ConsoleTestCase extends CondorcetTestCase
 {
     public const DEBIAN_INPUT_FILE = __DIR__ . '/../Tools/Converters/DebianData/leader2020_tally.txt';
     public const DAVIDHILL_INPUT_FILE = __DIR__ . '/../Tools/Converters/TidemanData/A77.HIL';
diff --git a/tests/src/ElectionTest.php b/tests/src/ElectionTest.php
index e7bd9948..58eb2602 100644
--- a/tests/src/ElectionTest.php
+++ b/tests/src/ElectionTest.php
@@ -610,7 +610,7 @@
     );
 
     unserialize(
-        file_get_contents(__DIR__.'/ElectionData/serialized_election_v3.2.0.txt')
+        file_get_contents(__DIR__ . '/ElectionData/serialized_election_v3.2.0.txt')
     );
 });
 
diff --git a/tests/src/Tools/Randomizers/ArrayRandomizerTest.php b/tests/src/Tools/Randomizers/ArrayRandomizerTest.php
index 8f6949a1..a8fdd1b5 100644
--- a/tests/src/Tools/Randomizers/ArrayRandomizerTest.php
+++ b/tests/src/Tools/Randomizers/ArrayRandomizerTest.php
@@ -4,7 +4,7 @@
 
 use CondorcetPHP\Condorcet\Tools\Randomizers\ArrayRandomizer;
 
-test('default random votes', function () {
+test('default random votes', function (): void {
     $votesRandomizer = new ArrayRandomizer(self::CANDIDATE_SET_1, self::SEED);
 
     for ($i = 0; $i < 10; $i++) {
@@ -14,7 +14,8 @@
         expect($nv)->toHaveCount(\count(self::CANDIDATE_SET_1));
     }
 });
-test('max candidates ranked', function () {
+
+test('max candidates ranked', function (): void {
     $votesRandomizer = new ArrayRandomizer(self::CANDIDATE_SET_1, self::SEED);
     $votesRandomizer->maxCandidatesRanked = 3;
 
@@ -27,7 +28,8 @@
         expect($nv)->toHaveCount($votesRandomizer->maxCandidatesRanked);
     }
 });
-test('min candidates ranked', function () {
+
+test('min candidates ranked', function (): void {
     $votesRandomizer = new ArrayRandomizer(self::CANDIDATE_SET_1, self::SEED);
     $votesRandomizer->minCandidatesRanked = 3;
 
@@ -47,7 +49,8 @@
     $variationsCount = \count(array_unique($variations));
     expect($variationsCount)->toBe(\count(self::CANDIDATE_SET_1) - $votesRandomizer->minCandidatesRanked + 1);
 });
-test('min and max candidates ranked', function () {
+
+test('min and max candidates ranked', function (): void {
     $votesRandomizer = new ArrayRandomizer(self::CANDIDATE_SET_1, self::SEED);
     $votesRandomizer->minCandidatesRanked = 3;
     $votesRandomizer->maxCandidatesRanked = 6;
@@ -67,7 +70,8 @@
     $variationsCount = \count(array_unique($variations));
     expect($variationsCount)->toBe($votesRandomizer->maxCandidatesRanked - $votesRandomizer->minCandidatesRanked + 1);
 });
-test('added ties', function () {
+
+test('added ties', function (): void {
     $votesRandomizer = new ArrayRandomizer(self::CANDIDATE_SET_2, self::SEED);
 
     $votesRandomizer->tiesProbability = 100;
@@ -91,7 +95,8 @@
     expect($nv)->toHaveCount(1);
     expect($nv[0])->toHaveCount(3);
 });
-test('added ties with array1', function () {
+
+test('added ties with array1', function (): void {
     $votesRandomizer = new ArrayRandomizer(self::CANDIDATE_SET_3, self::SEED);
 
     $votesRandomizer->tiesProbability = 100;
@@ -100,7 +105,8 @@
     expect($nv)->toHaveCount(3);
     expect($nv[2])->toHaveCount(2);
 });
-test('added ties with array2', function () {
+
+test('added ties with array2', function (): void {
     $votesRandomizer = new ArrayRandomizer(self::CANDIDATE_SET_1, self::SEED);
 
     $votesRandomizer->tiesProbability = 500;
@@ -109,7 +115,8 @@
     expect($nv)->toHaveCount(4);
     expect($nv[2])->toHaveCount(6);
 });
-test('seeds', function () {
+
+test('seeds', function (): void {
     // Test low seed
     $votesRandomizer = new ArrayRandomizer(self::CANDIDATE_SET_1, '42');
     expect($votesRandomizer->shuffle()[0])->toBe(self::CANDIDATE_SET_1[5]);
@@ -121,7 +128,7 @@
     expect($votesRandomizer->shuffle()[0])->toBe(self::CANDIDATE_SET_1[6]);
 
     // Test custom Randomizer
-    $r = new \Random\Randomizer(new \Random\Engine\PcgOneseq128XslRr64('abcdefghijklmnop'));
+    $r = new Random\Randomizer(new Random\Engine\PcgOneseq128XslRr64('abcdefghijklmnop'));
     $votesRandomizer = new ArrayRandomizer(self::CANDIDATE_SET_1, $r);
     expect($votesRandomizer->shuffle()[0])->toBe(self::CANDIDATE_SET_1[4]);
 
diff --git a/tests/src/Tools/Randomizers/RandomizerTestCase.php b/tests/src/Tools/Randomizers/RandomizerTestCase.php
index f51a3276..14b027f1 100644
--- a/tests/src/Tools/Randomizers/RandomizerTestCase.php
+++ b/tests/src/Tools/Randomizers/RandomizerTestCase.php
@@ -6,7 +6,7 @@
 
 use Tests\CondorcetTestCase;
 
-class RandomizerTestCase extends CondorcetTestCase
+abstract class RandomizerTestCase extends CondorcetTestCase
 {
     public const SEED = 'CondorcetSeed';