diff --git a/libraries/classes/TablePartitionDefinition.php b/libraries/classes/TablePartitionDefinition.php
index be9e8c8058..b639aacc43 100644
--- a/libraries/classes/TablePartitionDefinition.php
+++ b/libraries/classes/TablePartitionDefinition.php
@@ -9,7 +9,7 @@ use function array_merge;
 use function array_splice;
 use function min;
 
-class TablePartitionDefinition
+final class TablePartitionDefinition
 {
     /**
      * @param array|null $details Details that may be pre-filled
@@ -28,7 +28,7 @@ class TablePartitionDefinition
     /**
      * @return array
      */
-    protected static function generateDetails(): array
+    private static function generateDetails(): array
     {
         $partitionDetails = self::extractDetailsFromRequest();
 
@@ -55,7 +55,7 @@ class TablePartitionDefinition
      *
      * @return array
      */
-    protected static function extractDetailsFromRequest(): array
+    private static function extractDetailsFromRequest(): array
     {
         $partitionParams = [
             'partition_by' => null,
@@ -79,10 +79,11 @@ class TablePartitionDefinition
     /**
      * @param string $paramLabel Label searched in request
      */
-    protected static function extractPartitionCount(string $paramLabel): int
+    private static function extractPartitionCount(string $paramLabel): int
     {
         if (Core::isValid($_POST[$paramLabel], 'numeric')) {
             // MySQL's limit is 8192, so do not allow more
+            // @see https://dev.mysql.com/doc/refman/en/partitioning-limitations.html
             $count = min((int) $_POST[$paramLabel], 8192);
         } else {
             $count = 0;
@@ -96,7 +97,7 @@ class TablePartitionDefinition
      *
      * @return array
      */
-    protected static function extractPartitions(array $partitionDetails): array
+    private static function extractPartitions(array $partitionDetails): array
     {
         $partitionCount = $partitionDetails['partition_count'];
         $subpartitionCount = $partitionDetails['subpartition_count'];
@@ -151,7 +152,7 @@ class TablePartitionDefinition
             }
 
             // No subpartitions
-            if ($subpartitionCount <= 1 || $partitionDetails['can_have_subpartitions'] !== true) {
+            if ($subpartitionCount < 2 || $partitionDetails['can_have_subpartitions'] !== true) {
                 unset($partition['subpartitions'], $partition['subpartition_count']);
                 continue;
             }
diff --git a/test/classes/TablePartitionDefinitionTest.php b/test/classes/TablePartitionDefinitionTest.php
new file mode 100644
index 0000000000..c04226de27
--- /dev/null
+++ b/test/classes/TablePartitionDefinitionTest.php
@@ -0,0 +1,265 @@
+<?php
+
+declare(strict_types=1);
+
+namespace PhpMyAdmin\Tests;
+
+use PhpMyAdmin\TablePartitionDefinition;
+use PHPUnit\Framework\TestCase;
+
+use function count;
+
+/**
+ * @covers \PhpMyAdmin\TablePartitionDefinition
+ */
+class TablePartitionDefinitionTest extends TestCase
+{
+    /**
+     * @dataProvider providerGetDetails
+     */
+    public function testGetDetails(
+        string $partitionBy,
+        bool $canHaveSubpartitions,
+        bool $valueEnabled,
+        int $partitionCount,
+        int $subPartitionCount,
+        ?array $partitions
+    ): void {
+        $expected = [
+            'partition_by' => $partitionBy,
+            'partition_expr' => 'partition_expr',
+            'subpartition_by' => 'subpartition_by',
+            'subpartition_expr' => 'subpartition_expr',
+            'partition_count' => $partitionCount > 0 ? $partitionCount : '',
+            'subpartition_count' => $subPartitionCount > 0 ? $subPartitionCount : '',
+            'can_have_subpartitions' => $canHaveSubpartitions,
+            'value_enabled' => $valueEnabled,
+            'partitions' => [
+                [
+                    'name' => 'part0',
+                    'value_type' => '',
+                    'value' => '',
+                    'engine' => '',
+                    'comment' => '',
+                    'data_directory' => '',
+                    'index_directory' => '',
+                    'max_rows' => '',
+                    'min_rows' => '',
+                    'tablespace' => '',
+                    'node_group' => '',
+                    'prefix' => 'partitions[0]',
+                    'subpartition_count' => 2,
+                    'subpartitions' => [
+                        [
+                            'name' => 'part0_s0',
+                            'engine' => '',
+                            'comment' => '',
+                            'data_directory' => '',
+                            'index_directory' => '',
+                            'max_rows' => '',
+                            'min_rows' => '',
+                            'tablespace' => '',
+                            'node_group' => '',
+                            'prefix' => 'partitions[0][subpartitions][0]',
+                        ],
+                        [
+                            'name' => 'part0_s1',
+                            'engine' => '',
+                            'comment' => '',
+                            'data_directory' => '',
+                            'index_directory' => '',
+                            'max_rows' => '',
+                            'min_rows' => '',
+                            'tablespace' => '',
+                            'node_group' => '',
+                            'prefix' => 'partitions[0][subpartitions][1]',
+                        ],
+                    ],
+                ],
+                [
+                    'name' => 'p1',
+                    'value_type' => '',
+                    'value' => '',
+                    'engine' => '',
+                    'comment' => '',
+                    'data_directory' => '',
+                    'index_directory' => '',
+                    'max_rows' => '',
+                    'min_rows' => '',
+                    'tablespace' => '',
+                    'node_group' => '',
+                    'prefix' => 'partitions[1]',
+                    'subpartition_count' => 2,
+                    'subpartitions' => [
+                        [
+                            'name' => 'p1_s0',
+                            'engine' => '',
+                            'comment' => '',
+                            'data_directory' => '',
+                            'index_directory' => '',
+                            'max_rows' => '',
+                            'min_rows' => '',
+                            'tablespace' => '',
+                            'node_group' => '',
+                            'prefix' => 'partitions[1][subpartitions][0]',
+                        ],
+                        [
+                            'name' => 'p1_s1',
+                            'engine' => '',
+                            'comment' => '',
+                            'data_directory' => '',
+                            'index_directory' => '',
+                            'max_rows' => '',
+                            'min_rows' => '',
+                            'tablespace' => '',
+                            'node_group' => '',
+                            'prefix' => 'partitions[1][subpartitions][1]',
+                        ],
+                    ],
+                ],
+            ],
+        ];
+
+        if (! $canHaveSubpartitions && $partitionCount === 2) {
+            unset($expected['partitions'][0]['subpartition_count']);
+            unset($expected['partitions'][0]['subpartitions']);
+            unset($expected['partitions'][1]['subpartition_count']);
+            unset($expected['partitions'][1]['subpartitions']);
+        }
+
+        if ($partitionCount < 2) {
+            unset($expected['partitions']);
+        }
+
+        $_POST['partition_by'] = $partitionBy;
+        $_POST['partition_expr'] = 'partition_expr';
+        $_POST['subpartition_by'] = 'subpartition_by';
+        $_POST['subpartition_expr'] = 'subpartition_expr';
+        $_POST['partition_count'] = (string) $partitionCount;
+        $_POST['subpartition_count'] = (string) $subPartitionCount;
+        $_POST['partitions'] = $partitions;
+        $_POST['ignored_key'] = 'ignored_value';
+
+        $actual = TablePartitionDefinition::getDetails();
+        $this->assertEquals($expected, $actual);
+    }
+
+    /**
+     * @psalm-return array<string, array{
+     *   0: string, 1: bool, 2: bool, 3: int, 4: int, 5: array<string, string|array<string, string>[]>[]|null
+     * }>
+     */
+    public function providerGetDetails(): array
+    {
+        return [
+            'partition by RANGE' => ['RANGE', true, true, 2, 2, [['name' => 'part0']]],
+            'partition by RANGE COLUMNS' => ['RANGE COLUMNS', true, true, 2, 2, [['name' => 'part0']]],
+            'partition by LIST' => ['LIST', true, true, 2, 2, [['name' => 'part0']]],
+            'partition by LIST COLUMNS' => ['LIST COLUMNS', true, true, 2, 2, [['name' => 'part0']]],
+            'partition by HASH' => ['HASH', false, false, 2, 2, [['name' => 'part0']]],
+            'partition count === 0' => ['RANGE', false, true, 0, 0, null],
+            'partition count === 1' => ['RANGE', false, true, 1, 1, null],
+            'more partitions than the partition count' => [
+                'RANGE',
+                true,
+                true,
+                2,
+                2,
+                [['name' => 'part0'], ['name' => 'p1'], ['name' => 'p2']],
+            ],
+            'more subpartitions than the subpartition count' => [
+                'RANGE',
+                true,
+                true,
+                2,
+                2,
+                [
+                    [
+                        'name' => 'part0',
+                        'subpartitions' => [
+                            [
+                                'name' => 'part0_s0',
+                                'engine' => '',
+                                'comment' => '',
+                                'data_directory' => '',
+                                'index_directory' => '',
+                                'max_rows' => '',
+                                'min_rows' => '',
+                                'tablespace' => '',
+                                'node_group' => '',
+                                'prefix' => 'partitions[1][subpartitions][0]',
+                            ],
+                            [
+                                'name' => 'part0_s1',
+                                'engine' => '',
+                                'comment' => '',
+                                'data_directory' => '',
+                                'index_directory' => '',
+                                'max_rows' => '',
+                                'min_rows' => '',
+                                'tablespace' => '',
+                                'node_group' => '',
+                                'prefix' => 'partitions[1][subpartitions][1]',
+                            ],
+                            [
+                                'name' => 'part0_s1',
+                                'engine' => '',
+                                'comment' => '',
+                                'data_directory' => '',
+                                'index_directory' => '',
+                                'max_rows' => '',
+                                'min_rows' => '',
+                                'tablespace' => '',
+                                'node_group' => '',
+                                'prefix' => 'partitions[1][subpartitions][1]',
+                            ],
+                        ],
+                    ],
+                ],
+            ],
+        ];
+    }
+
+    public function testGetDetailsWithoutPostValues(): void
+    {
+        $_POST = [];
+        $expected = [
+            'partition_by' => null,
+            'partition_expr' => null,
+            'subpartition_by' => null,
+            'subpartition_expr' => null,
+            'partition_count' => '',
+            'subpartition_count' => '',
+            'can_have_subpartitions' => false,
+            'value_enabled' => false,
+        ];
+
+        $actual = TablePartitionDefinition::getDetails($expected);
+        $this->assertEquals($expected, $actual);
+
+        $actual = TablePartitionDefinition::getDetails();
+        $this->assertEquals($expected, $actual);
+    }
+
+    /**
+     * @dataProvider providerGetDetailsWithMaxPartitions
+     */
+    public function testGetDetailsWithMaxPartitions(int $partitionCount, string $partitionCountFromPost): void
+    {
+        $_POST = ['partition_count' => $partitionCountFromPost];
+        $actual = TablePartitionDefinition::getDetails();
+        $this->assertArrayHasKey('partition_count', $actual);
+        $this->assertArrayHasKey('partitions', $actual);
+        $this->assertSame($partitionCount, $actual['partition_count']);
+        $this->assertIsArray($actual['partitions']);
+        $this->assertEquals($partitionCount, count($actual['partitions']));
+    }
+
+    /**
+     * @psalm-return array{0: int, 1: string}[]
+     */
+    public function providerGetDetailsWithMaxPartitions(): array
+    {
+        return ['count within the limit' => [8192, '8192'], 'count above the limit' => [8192, '8193']];
+    }
+}
diff --git a/test/classes/UserPasswordTest.php b/test/classes/UserPasswordTest.php
new file mode 100644
index 0000000000..c799104f4f
--- /dev/null
+++ b/test/classes/UserPasswordTest.php
@@ -0,0 +1,77 @@
+<?php
+
+declare(strict_types=1);
+
+namespace PhpMyAdmin\Tests;
+
+use PhpMyAdmin\Message;
+use PhpMyAdmin\Relation;
+use PhpMyAdmin\RelationCleanup;
+use PhpMyAdmin\Server\Plugins;
+use PhpMyAdmin\Server\Privileges;
+use PhpMyAdmin\Template;
+use PhpMyAdmin\UserPassword;
+
+use function str_repeat;
+
+/**
+ * @covers \PhpMyAdmin\UserPassword
+ */
+class UserPasswordTest extends AbstractTestCase
+{
+    /** @var UserPassword */
+    private $object;
+
+    protected function setUp(): void
+    {
+        parent::setUp();
+
+        $relation = new Relation($GLOBALS['dbi']);
+        $serverPrivileges = new Privileges(
+            new Template(),
+            $GLOBALS['dbi'],
+            $relation,
+            new RelationCleanup($GLOBALS['dbi'], $relation),
+            new Plugins($GLOBALS['dbi'])
+        );
+        $this->object = new UserPassword($serverPrivileges);
+    }
+
+    /**
+     * @dataProvider providerSetChangePasswordMsg
+     */
+    public function testSetChangePasswordMsg(
+        bool $error,
+        Message $message,
+        string $noPassword,
+        string $password,
+        string $passwordConfirmation
+    ): void {
+        $_POST['nopass'] = $noPassword;
+        $_POST['pma_pw'] = $password;
+        $_POST['pma_pw2'] = $passwordConfirmation;
+        $this->assertEquals(['error' => $error, 'msg' => $message], $this->object->setChangePasswordMsg());
+    }
+
+    /**
+     * @psalm-return array{0: bool, 1: Message, 2: string, 3: string, 4: string}[]
+     */
+    public function providerSetChangePasswordMsg(): array
+    {
+        return [
+            [false, Message::success('The profile has been updated.'), '1', '', ''],
+            [true, Message::error('The password is empty!'), '0', '', ''],
+            [true, Message::error('The password is empty!'), '0', 'a', ''],
+            [true, Message::error('The password is empty!'), '0', '', 'a'],
+            [true, Message::error('The passwords aren\'t the same!'), '0', 'a', 'b'],
+            [true, Message::error('Password is too long!'), '0', str_repeat('a', 257), str_repeat('a', 257)],
+            [
+                false,
+                Message::success('The profile has been updated.'),
+                '0',
+                str_repeat('a', 256),
+                str_repeat('a', 256),
+            ],
+        ];
+    }
+}