diff --git a/src/Container/GenericContainer.php b/src/Container/GenericContainer.php
index ea85e7d..8afa2b1 100644
--- a/src/Container/GenericContainer.php
+++ b/src/Container/GenericContainer.php
@@ -16,10 +16,12 @@ use Docker\API\Model\PortBinding;
 use Docker\Docker;
 use Docker\Stream\CreateImageStream;
 use InvalidArgumentException;
+use RuntimeException;
 use Testcontainers\ContainerClient\DockerContainerClient;
 use Testcontainers\Utils\PortGenerator\PortGenerator;
 use Testcontainers\Utils\PortGenerator\RandomUniquePortGenerator;
 use Testcontainers\Utils\PortNormalizer;
+use Testcontainers\Utils\TarBuilder;
 use Testcontainers\Wait\WaitForContainer;
 use Testcontainers\Wait\WaitStrategy;
 
@@ -58,8 +60,28 @@ class GenericContainer implements TestContainer
     protected PortGenerator $portGenerator;
 
     protected bool $isPrivileged = false;
+
     protected ?string $networkName = null;
 
+    protected ?string $user = null;
+
+    protected ?string $workingDir = null;
+
+    /**
+     * @var array<array{source: string, target: string, mode?: int}>
+     */
+    protected array $filesToCopy = [];
+
+    /**
+     * @var array<array{source: string, target: string, mode?: int}>
+     */
+    protected array $directoriesToCopy = [];
+
+    /**
+     * @var array<array{content: string, target: string, mode?: int}>
+     */
+    protected array $contentsToCopy = [];
+
     protected int $startAttempts = 0;
     protected const MAX_START_ATTEMPTS = 2;
 
@@ -94,6 +116,39 @@ class GenericContainer implements TestContainer
         return $this;
     }
 
+    /**
+     * @param array<array{source: string, target: string, mode?: int}> $files
+     */
+    public function withCopyFilesToContainer(array $files): static
+    {
+        foreach ($files as $file) {
+            $this->filesToCopy[] = $file;
+        }
+        return $this;
+    }
+
+    /**
+     * @param array<array{source: string, target: string, mode?: int}> $directories
+     */
+    public function withCopyDirectoriesToContainer(array $directories): static
+    {
+        foreach ($directories as $directory) {
+            $this->directoriesToCopy[] = $directory;
+        }
+        return $this;
+    }
+
+    /**
+     * @param array<array{content: string, target: string, mode?: int}> $contents
+     */
+    public function withCopyContentToContainer(array $contents): static
+    {
+        foreach ($contents as $content) {
+            $this->contentsToCopy[] = $content;
+        }
+        return $this;
+    }
+
     public function withEntryPoint(string $entryPoint): static
     {
         $this->entryPoint = $entryPoint;
@@ -230,6 +285,20 @@ class GenericContainer implements TestContainer
         return $this;
     }
 
+    public function withUser(string $user): static
+    {
+        $this->user = $user;
+
+        return $this;
+    }
+
+    public function withWorkingDir(string $workingDir): static
+    {
+        $this->workingDir = $workingDir;
+
+        return $this;
+    }
+
     public function start(): StartedGenericContainer
     {
         $this->startAttempts++;
@@ -244,7 +313,7 @@ class GenericContainer implements TestContainer
             $this->id = $containerCreateResponse?->getId() ?? '';
         } catch (ContainerCreateNotFoundException) {
             if ($this->startAttempts >= self::MAX_START_ATTEMPTS) {
-                throw new \RuntimeException("Failed to start container after pulling image.");
+                throw new RuntimeException("Failed to start container after pulling image.");
             }
             // If the image is not found, pull it and try again
             // TODO: add withPullPolicy support
@@ -254,12 +323,84 @@ class GenericContainer implements TestContainer
 
         $this->dockerClient->containerStart($this->id);
 
+        if ($this->filesToCopy !== [] || $this->directoriesToCopy !== [] || $this->contentsToCopy !== []) {
+            $this->copyToContainer();
+        }
+
         $startedContainer = new StartedGenericContainer($this->id);
         $this->waitStrategy->wait($startedContainer);
 
         return $startedContainer;
     }
 
+    /**
+     * Uploads a tar archive containing files/directories/content to the container,
+     * extracting it into a chosen directory (`$containerPath`). Allows setting
+     * Docker's `noOverwriteDirNonDir` and `copyUIDGID` query parameters.
+     *
+     * @param string $containerPath Path within the container to extract the tar contents. Must be a directory in the container.
+     * @param bool $noOverwriteDirNonDir If true, Docker will error if it would replace an existing directory with a non-directory and vice versa.
+     * @param bool $copyUIDGID If true, Docker will attempt to preserve UID/GID from the tar entries.
+     * @throws RuntimeException|InvalidArgumentException
+     */
+    protected function copyToContainer(
+        string $containerPath = '/',
+        bool $noOverwriteDirNonDir = false,
+        bool $copyUIDGID = false
+    ): void {
+        $tarBuilder = new TarBuilder();
+        foreach ($this->filesToCopy as $file) {
+            $tarBuilder->addFile($file['source'], $file['target'], $file['mode'] ?? null);
+        }
+
+        foreach ($this->directoriesToCopy as $directory) {
+            $tarBuilder->addDirectory($directory['source'], $directory['target'], $directory['mode'] ?? null);
+        }
+
+        foreach ($this->contentsToCopy as $content) {
+            $tarBuilder->addContent($content['content'], $content['target'], $content['mode'] ?? null);
+        }
+
+        $tarFilePath = $tarBuilder->buildTarArchive();
+
+        if (!is_file($tarFilePath)) {
+            throw new RuntimeException("Tar file does not exist at: $tarFilePath");
+        }
+
+        $handle = fopen($tarFilePath, 'rb');
+
+        if ($handle === false) {
+            throw new RuntimeException("Cannot open temporary tar archive at: $tarFilePath");
+        }
+
+        $queryParams = [
+            'path' => $containerPath,
+        ];
+
+        if ($noOverwriteDirNonDir) {
+            $queryParams['noOverwriteDirNonDir'] = 'true';
+        }
+
+        if ($copyUIDGID) {
+            $queryParams['copyUIDGID'] = 'true';
+        }
+
+        /**
+         * TODO: should be improved. Currently without using dummy $result or FETCH_RESPONSE, the request is failing.
+         * Probably an issue with the beluga-php/docker-php client library.
+         * */
+        $result = $this->dockerClient->putContainerArchive(
+            $this->id,
+            $handle,
+            $queryParams,
+            $this->dockerClient::FETCH_RESPONSE
+        );
+
+        fclose($handle);
+        unlink($tarFilePath);
+    }
+
+
     protected function createContainerConfig(): ContainersCreatePostBody
     {
         $containerCreatePostBody = new ContainersCreatePostBody();
@@ -267,6 +408,8 @@ class GenericContainer implements TestContainer
         $containerCreatePostBody->setCmd($this->command);
         $containerCreatePostBody->setLabels($this->labels);
         $containerCreatePostBody->setHostname($this->hostname);
+        $containerCreatePostBody->setWorkingDir($this->workingDir);
+        $containerCreatePostBody->setUser($this->user);
 
         $envs = array_map(static fn ($key, $value) => "$key=$value", array_keys($this->env), $this->env);
         $containerCreatePostBody->setEnv($envs);
diff --git a/src/Utils/TarBuilder.php b/src/Utils/TarBuilder.php
new file mode 100644
index 0000000..ba615e7
--- /dev/null
+++ b/src/Utils/TarBuilder.php
@@ -0,0 +1,293 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Testcontainers\Utils;
+
+use InvalidArgumentException;
+use RecursiveDirectoryIterator;
+use RecursiveIteratorIterator;
+use RuntimeException;
+use SplFileInfo;
+
+class TarBuilder
+{
+    /**
+     * @var array<array{source: string, target: string, mode: int|null}>
+     */
+    private array $files = [];
+
+    /**
+     * @var array<array{source: string, target: string, mode: int|null}>
+     */
+    private array $directories = [];
+
+    /**
+     * @var array<array{content: string, target: string, mode: int|null}>
+     */
+    private array $contents = [];
+
+    /**
+     * Add a single file from the local filesystem.
+     */
+    public function addFile(string $source, string $target, ?int $mode = null): self
+    {
+        if (!is_file($source)) {
+            throw new InvalidArgumentException("Invalid file path: {$source}");
+        }
+        if (empty($target)) {
+            throw new InvalidArgumentException("Target path cannot be empty.");
+        }
+        if ($mode !== null && ($mode < 0 || $mode > 0o777)) {
+            throw new InvalidArgumentException("Invalid mode for file: {$mode}");
+        }
+        $this->files[] = [
+            'source' => $source,
+            'target' => $target,
+            'mode'   => $mode,
+        ];
+        return $this;
+    }
+
+    /**
+     * Add a directory (recursively) from the local filesystem.
+     */
+    public function addDirectory(string $source, string $target, ?int $mode = null): self
+    {
+        $this->directories[] = [
+            'source' => $source,
+            'target' => $target,
+            'mode'   => $mode,
+        ];
+        return $this;
+    }
+
+    /**
+     * Add inline string content that should become a file in the tar.
+     */
+    public function addContent(string $content, string $target, ?int $mode = null): self
+    {
+        $this->contents[] = [
+            'content' => $content,
+            'target'  => $target,
+            'mode'    => $mode,
+        ];
+        return $this;
+    }
+
+    /**
+     * Builds the .tar archive from everything that was added (files, directories, contents).
+     *
+     * Returns the full path to the created .tar file.
+     */
+    public function buildTarArchive(): string
+    {
+        $tempDir = $this->createTempDir();
+
+        $this->copyFilesToLocalDir($tempDir, $this->files);
+        $this->copyDirectoriesToLocalDir($tempDir, $this->directories);
+        $this->createFilesFromContent($tempDir, $this->contents);
+
+        $tarFilePath = $this->createTempTarPath();
+        $this->runTarCommand($tarFilePath, $tempDir);
+        $this->removeDirectoryRecursively($tempDir);
+
+        return $tarFilePath;
+    }
+
+    public function clear(): void
+    {
+        $this->files = [];
+        $this->directories = [];
+        $this->contents = [];
+    }
+
+    private function createTempDir(): string
+    {
+        $tmpDirName = tempnam(sys_get_temp_dir(), 'tc_files_');
+        if ($tmpDirName === false) {
+            throw new RuntimeException("Failed to create a temp file for tar data");
+        }
+        // tempnam() creates a file; remove it and create directory instead
+        unlink($tmpDirName);
+
+        if (!mkdir($tmpDirName) && !is_dir($tmpDirName)) {
+            throw new RuntimeException("Failed to create temp directory: {$tmpDirName}");
+        }
+
+        return $tmpDirName;
+    }
+
+    private function createTempTarPath(): string
+    {
+        $tmpFile = tempnam(sys_get_temp_dir(), 'tc_tar_');
+
+        if ($tmpFile === false) {
+            throw new RuntimeException("Failed to create temp file for tar archive");
+        }
+
+        $tarFilePath = $tmpFile . '.tar';
+
+        if (!rename($tmpFile, $tarFilePath)) {
+            throw new RuntimeException("Failed renaming temp file to .tar");
+        }
+        return $tarFilePath;
+    }
+
+    private function runTarCommand(string $tarFilePath, string $sourceDir): void
+    {
+        // without --disable-copyfile and --no-xattrs combination, tar will fail on macOS
+        $cmd = sprintf(
+            'tar --no-xattrs --disable-copyfile -cf %s -C %s . 2>&1',
+            escapeshellarg($tarFilePath),
+            escapeshellarg($sourceDir)
+        );
+
+        exec($cmd, $output, $exitCode);
+
+        if ($exitCode !== 0) {
+            $errorText = implode("\n", $output);
+            throw new RuntimeException("Failed to create tar archive:\n{$errorText}");
+        }
+    }
+
+    private function removeDirectoryRecursively(string $dir): void
+    {
+        if (!is_dir($dir)) {
+            return;
+        }
+
+        $iterator = new RecursiveIteratorIterator(
+            new RecursiveDirectoryIterator($dir, \FilesystemIterator::SKIP_DOTS),
+            RecursiveIteratorIterator::CHILD_FIRST
+        );
+
+        foreach ($iterator as $item) {
+            if (!$item instanceof SplFileInfo) {
+                continue;
+            }
+            $path = $item->getRealPath();
+            if ($item->isDir()) {
+                rmdir($path);
+            } else {
+                unlink($path);
+            }
+        }
+        rmdir($dir);
+    }
+
+    /**
+     * @param array<array{source: string, target: string, mode: int|null}> $files
+     */
+    private function copyFilesToLocalDir(string $tempDir, array $files): void
+    {
+        foreach ($files as $file) {
+            $source = $file['source'];
+            $target = $file['target'];
+            $mode   = $file['mode'] ?? null;
+
+            if (!is_file($source)) {
+                throw new InvalidArgumentException("File not found: $source");
+            }
+            $destPath = $this->makeDestPath($tempDir, $target);
+            $this->ensureParentDir($destPath);
+
+            if (!copy($source, $destPath)) {
+                throw new RuntimeException("Failed to copy file $source to $destPath");
+            }
+            if ($mode !== null) {
+                chmod($destPath, $mode);
+            }
+        }
+    }
+
+    /**
+     * @param array<array{source: string, target: string, mode: int|null}> $directories
+     */
+    private function copyDirectoriesToLocalDir(string $tempDir, array $directories): void
+    {
+        foreach ($directories as $dir) {
+            $source = $dir['source'];
+            $target = $dir['target'];
+            $mode   = $dir['mode'] ?? null;
+
+            if (!is_dir($source)) {
+                throw new InvalidArgumentException("Directory not found: $source");
+            }
+            $destPath = $this->makeDestPath($tempDir, $target);
+            $this->copyDirectoryRecursively($source, $destPath);
+
+            if ($mode !== null) {
+                chmod($destPath, $mode);
+            }
+        }
+    }
+
+    /**
+     * @param array<array{content: string, target: string, mode: int|null}> $contents
+     */
+    private function createFilesFromContent(string $tempDir, array $contents): void
+    {
+        foreach ($contents as $content) {
+            $data   = $content['content'];
+            $target = $content['target'];
+            $mode   = $content['mode'] ?? null;
+
+            $destPath = $this->makeDestPath($tempDir, $target);
+            $this->ensureParentDir($destPath);
+
+            file_put_contents($destPath, $data);
+            if ($mode !== null) {
+                chmod($destPath, $mode);
+            }
+        }
+    }
+
+    private function copyDirectoryRecursively(string $sourceDir, string $destDir): void
+    {
+        $this->ensureParentDir($destDir);
+
+        $innerIterator = new RecursiveDirectoryIterator($sourceDir, \FilesystemIterator::SKIP_DOTS);
+
+        /** @var RecursiveIteratorIterator<RecursiveDirectoryIterator> $iterator */
+        $iterator = new RecursiveIteratorIterator(
+            $innerIterator,
+            RecursiveIteratorIterator::SELF_FIRST
+        );
+
+        foreach ($iterator as $item) {
+            if (!$item instanceof SplFileInfo) {
+                continue;
+            }
+
+            /** @var RecursiveDirectoryIterator $innerIterator */
+            $innerIterator = $iterator->getInnerIterator();
+            $subPathName = $innerIterator->getSubPathName();
+            $targetPath = $destDir . '/' . $subPathName;
+
+            // Ensure the parent directory for the target path exists
+            $this->ensureParentDir($targetPath);
+
+            if ($item->isDir()) {
+                if (!mkdir($targetPath, 0o777, true) && !is_dir($targetPath)) {
+                    throw new RuntimeException(sprintf('Directory "%s" was not created', $targetPath));
+                }
+            } else {
+                copy($item->getPathname(), $targetPath);
+            }
+        }
+    }
+
+    private function makeDestPath(string $tempDir, string $target): string
+    {
+        return rtrim($tempDir, '/') . '/' . ltrim($target, '/');
+    }
+
+    private function ensureParentDir(string $path): void
+    {
+        $parent = dirname($path);
+        if (!is_dir($parent) && !mkdir($parent, 0o777, true) && !is_dir($parent)) {
+            throw new RuntimeException("Failed to create parent directory: $parent");
+        }
+    }
+}
diff --git a/tests/Integration/GenericContainerTest.php b/tests/Integration/GenericContainerTest.php
index 7590db3..2a7c9e9 100644
--- a/tests/Integration/GenericContainerTest.php
+++ b/tests/Integration/GenericContainerTest.php
@@ -6,6 +6,7 @@ namespace Testcontainers\Tests\Integration;
 
 use Docker\API\Model\ContainersIdJsonGetResponse200;
 use PHPUnit\Framework\TestCase;
+use RuntimeException;
 use Testcontainers\Container\GenericContainer;
 use Testcontainers\Utils\PortGenerator\FixedPortGenerator;
 use Testcontainers\Wait\WaitForHostPort;
@@ -24,6 +25,94 @@ class GenericContainerTest extends TestCase
         $container->stop();
     }
 
+    public function testShouldCopyContentToContainer(): void
+    {
+        $inlineContent = 'hello world';
+
+        $container = (new GenericContainer('alpine'))
+            ->withCommand(['tail', '-f', '/dev/null'])
+            ->withCopyContentToContainer([[
+                'content' => $inlineContent,
+                'target' => '/tmp/inline.txt',
+            ]])
+            ->start();
+
+        $output = $container->exec(['cat', '/tmp/inline.txt']);
+
+        self::assertSame($inlineContent, $output);
+
+        $container->stop();
+    }
+
+    public function testShouldCopyDirectoryToContainer(): void
+    {
+        $testDir = sys_get_temp_dir() . '/copy-dir-test';
+        if (!is_dir($testDir)) {
+            mkdir($testDir);
+        }
+        file_put_contents($testDir . '/file1.txt', 'file1 contents');
+        file_put_contents($testDir . '/file2.txt', 'file2 contents');
+
+        $container = (new GenericContainer('alpine'))
+            ->withCommand(['tail', '-f', '/dev/null'])
+            ->withCopyDirectoriesToContainer([[
+                'source' => $testDir,
+                'target' => '/test-dir',
+            ]])
+            ->start();
+
+        $output1 = $container->exec(['cat', '/test-dir/file1.txt']);
+        $output2 = $container->exec(['cat', '/test-dir/file2.txt']);
+
+        self::assertSame('file1 contents', $output1);
+        self::assertSame('file2 contents', $output2);
+
+        $container->stop();
+    }
+
+    public function testShouldCopyFileToContainer(): void
+    {
+        $localFilePath = sys_get_temp_dir() . '/copy-file-test.txt';
+        file_put_contents($localFilePath, 'hello from file');
+
+        $container = (new GenericContainer('alpine'))
+            ->withCommand(['tail', '-f', '/dev/null'])
+            ->withCopyFilesToContainer([[
+                'source' => $localFilePath,
+                'target' => '/tmp/test-file.txt',
+            ]])
+            ->start();
+
+        $output = $container->exec(['cat', '/tmp/test-file.txt']);
+
+        self::assertSame('hello from file', $output);
+
+        $container->stop();
+    }
+
+    public function testShouldCopyFileWithPermissions(): void
+    {
+        $localFilePath = sys_get_temp_dir() . '/copy-perms-test.txt';
+        file_put_contents($localFilePath, 'check perms');
+
+        $mode = 0o777;
+
+        $container = (new GenericContainer('alpine'))
+            ->withCommand(['tail', '-f', '/dev/null'])
+            ->withCopyFilesToContainer([[
+                'source' => $localFilePath,
+                'target' => '/tmp/perm-file.txt',
+                'mode'   => $mode,
+            ]])
+            ->start();
+
+        $output = $container->exec(['stat', '-c', '%a', '/tmp/perm-file.txt']);
+
+        self::assertSame('777', trim($output));
+
+        $container->stop();
+    }
+
     /**
      * @throws \JsonException
      */
@@ -41,6 +130,68 @@ class GenericContainerTest extends TestCase
         $container->stop();
     }
 
+    public function testShouldSetLabels(): void
+    {
+        $labels = [
+            'label-1' => 'value-1',
+            'label-2' => 'value-2',
+        ];
+        $container = (new GenericContainer('alpine'))
+            ->withLabels($labels)
+            ->withCommand(['tail', '-f', '/dev/null'])
+            ->start();
+
+        /** @var ContainersIdJsonGetResponse200|null $inspectResult */
+        $inspectResult = $container->getClient()->containerInspect($container->getId());
+        $this->assertArrayHasKey('label-1', (array)$inspectResult?->getConfig()?->getLabels());
+        $this->assertSame('value-1', ((array)$inspectResult?->getConfig()?->getLabels())['label-1']);
+        $this->assertArrayHasKey('label-2', (array)$inspectResult?->getConfig()?->getLabels());
+        $this->assertSame('value-2', ((array)$inspectResult?->getConfig()?->getLabels())['label-2']);
+
+        $container->stop();
+    }
+
+    public function testShouldSetName(): void
+    {
+        $name = 'test-container-name';
+        $container = (new GenericContainer('alpine'))
+            ->withName($name)
+            ->withCommand(['tail', '-f', '/dev/null'])
+            ->start();
+
+        /** @var ContainersIdJsonGetResponse200|null $inspectResult */
+        $inspectResult = $container->getClient()->containerInspect($container->getId());
+        $this->assertSame('/'.$name, $inspectResult?->getName());
+
+        $container->stop();
+    }
+
+    public function testShouldSetUser(): void
+    {
+        $container = (new GenericContainer('alpine'))
+            ->withUser('nobody')
+            ->withCommand(['tail', '-f', '/dev/null'])
+            ->start();
+
+        $output = $container->exec(['whoami']);
+        $this->assertStringContainsString('nobody', $output);
+
+        $container->stop();
+    }
+
+    public function testShouldSetWorkingDir(): void
+    {
+        $container = (new GenericContainer('alpine'))
+            ->withWorkingDir('/tmp')
+            ->withCommand(['tail', '-f', '/dev/null'])
+            ->start();
+
+        $output = $container->exec(['pwd']);
+        $this->assertStringContainsString('/tmp', $output);
+
+        $container->stop();
+    }
+
     public function testShouldCaptureStderrWhenCommandFails(): void
     {
         $container = (new GenericContainer('alpine'))
@@ -66,6 +217,26 @@ class GenericContainerTest extends TestCase
         $container->stop();
     }
 
+    public function testShouldSetHealthCheckCommand(): void
+    {
+        $container = (new GenericContainer('alpine'))
+            ->withCommand(['tail', '-f', '/dev/null'])
+            ->withHealthCheckCommand('echo "healthy" || exit 1')
+            ->start();
+
+        /** @var ContainersIdJsonGetResponse200|null $inspectResult */
+        $inspectResult = $container->getClient()->containerInspect($container->getId());
+        $healthConfig = $inspectResult?->getConfig()?->getHealthcheck();
+
+        $this->assertNotNull($healthConfig);
+        $this->assertEquals(['CMD-SHELL', 'echo "healthy" || exit 1'], $healthConfig->getTest());
+        $this->assertSame(1000000000, $healthConfig->getInterval());
+        $this->assertSame(3000000000, $healthConfig->getTimeout());
+        $this->assertSame(3, $healthConfig->getRetries());
+
+        $container->stop();
+    }
+
     public function testShouldSetEntrypoint(): void
     {
         $container = (new GenericContainer('cristianrgreco/testcontainer:1.1.14'))
@@ -95,6 +266,8 @@ class GenericContainerTest extends TestCase
 
         $result = $container->exec(["cat", $containerPath.'/test.txt']);
         self::assertSame('hello world', $result);
+
+        $container->stop();
     }
 
     public function testShouldSetPrivilegedMode(): void
@@ -109,5 +282,7 @@ class GenericContainerTest extends TestCase
         $privileged = $inspectResult?->getHostConfig()?->getPrivileged();
 
         self::assertTrue($privileged);
+
+        $container->stop();
     }
 }
diff --git a/tests/Unit/Utils/TarBuilderTest.php b/tests/Unit/Utils/TarBuilderTest.php
new file mode 100644
index 0000000..b2f326f
--- /dev/null
+++ b/tests/Unit/Utils/TarBuilderTest.php
@@ -0,0 +1,218 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Testcontainers\Tests\Unit\Utils;
+
+use InvalidArgumentException;
+use PHPUnit\Framework\TestCase;
+use RecursiveDirectoryIterator;
+use RecursiveIteratorIterator;
+use RuntimeException;
+use SplFileInfo;
+use Testcontainers\Utils\TarBuilder;
+
+/**
+ * @covers \Testcontainers\Utils\TarBuilder
+ */
+class TarBuilderTest extends TestCase
+{
+    private const TEST_CONTENT = 'hello world';
+    private string $tempDir;
+
+    protected function setUp(): void
+    {
+        parent::setUp();
+        $this->tempDir = sys_get_temp_dir() . '/tarbuilder_test_' . uniqid('', true);
+        mkdir($this->tempDir);
+    }
+
+    protected function tearDown(): void
+    {
+        $this->removeDirectoryRecursively($this->tempDir);
+        parent::tearDown();
+    }
+
+    public function testShouldAddSingleFile(): void
+    {
+        $sourceFile = $this->tempDir . '/file.txt';
+        file_put_contents($sourceFile, self::TEST_CONTENT);
+
+        $tarBuilder = new TarBuilder();
+        $tarBuilder->addFile($sourceFile, 'mydir/file_in_tar.txt', 0o644);
+
+        $tarPath = $tarBuilder->buildTarArchive();
+
+        $this->assertFileExists($tarPath, 'Tar file was not created');
+
+        $extractDir = $this->tempDir . '/extract';
+        mkdir($extractDir);
+        $this->extractTar($tarPath, $extractDir);
+
+        $extractedFile = $extractDir . '/mydir/file_in_tar.txt';
+        $this->assertFileExists($extractedFile);
+        $this->assertSame(self::TEST_CONTENT, file_get_contents($extractedFile));
+
+        $perms = substr(sprintf('%o', fileperms($extractedFile)), -3);
+        $this->assertSame('644', $perms, 'Expected file mode 0644');
+    }
+
+    public function testShouldAddDirectoryRecursively(): void
+    {
+        $localDir = $this->tempDir . '/localdir';
+        mkdir($localDir);
+        file_put_contents($localDir . '/one.txt', 'file1');
+        file_put_contents($localDir . '/two.txt', 'file2');
+
+        $tarBuilder = new TarBuilder();
+        $tarBuilder->addDirectory($localDir, 'mydir', 0o755);
+        $tarPath = $tarBuilder->buildTarArchive();
+
+        $this->assertFileExists($tarPath);
+
+        $extractDir = $this->tempDir . '/extractdir';
+        mkdir($extractDir);
+        $this->extractTar($tarPath, $extractDir);
+
+        $oneExtracted = $extractDir . '/mydir/one.txt';
+        $twoExtracted = $extractDir . '/mydir/two.txt';
+        $this->assertFileExists($oneExtracted);
+        $this->assertFileExists($twoExtracted);
+
+        $this->assertSame('file1', file_get_contents($oneExtracted));
+        $this->assertSame('file2', file_get_contents($twoExtracted));
+
+        $dirPerms = substr(sprintf('%o', fileperms($extractDir . '/mydir')), -3);
+        $this->assertSame('755', $dirPerms, 'Expected directory mode 0755');
+    }
+
+    public function testShouldAddInlineContent(): void
+    {
+        $content = "Inline content test\nLine2";
+
+        $tarBuilder = new TarBuilder();
+        $tarBuilder->addContent($content, 'some/path/inline.txt', 0o777);
+        $tarPath = $tarBuilder->buildTarArchive();
+
+        $this->assertFileExists($tarPath);
+
+        $extractDir = $this->tempDir . '/extractContent';
+        mkdir($extractDir);
+        $this->extractTar($tarPath, $extractDir);
+
+        $inlineExtracted = $extractDir . '/some/path/inline.txt';
+        $this->assertFileExists($inlineExtracted);
+        $this->assertSame($content, file_get_contents($inlineExtracted));
+
+        $perms = substr(sprintf('%o', fileperms($inlineExtracted)), -3);
+        $this->assertSame('777', $perms, 'Expected file mode 0777');
+    }
+
+    public function testShouldFailOnInvalidFilePath(): void
+    {
+        $tarBuilder = new TarBuilder();
+        $this->expectException(InvalidArgumentException::class);
+        $tarBuilder->addFile('/some/nonexistent/file', 'target.txt');
+    }
+
+    public function testShouldFailOnEmptyTarget(): void
+    {
+        $localFile = $this->tempDir . '/somefile.txt';
+        file_put_contents($localFile, 'abc');
+
+        $tarBuilder = new TarBuilder();
+        $this->expectException(InvalidArgumentException::class);
+        $tarBuilder->addFile($localFile, '');
+    }
+
+    public function testShouldFailOnInvalidMode(): void
+    {
+        $localFile = $this->tempDir . '/somefile.txt';
+        file_put_contents($localFile, 'abc');
+
+        $tarBuilder = new TarBuilder();
+        $this->expectException(InvalidArgumentException::class);
+        $tarBuilder->addFile($localFile, 'target.txt', 9999);
+    }
+
+    public function testShouldCreateEmptyTarIfNoItemsAdded(): void
+    {
+        $tarBuilder = new TarBuilder();
+
+        $tarPath = $tarBuilder->buildTarArchive();
+        $this->assertFileExists($tarPath);
+
+        $extractDir = $this->tempDir . '/extractEmpty';
+        mkdir($extractDir);
+        $this->extractTar($tarPath, $extractDir);
+
+        $scanned = array_diff(scandir($extractDir), ['.', '..']);
+        $this->assertCount(0, $scanned, 'Expected empty directory');
+    }
+
+    public function testShouldClearItems(): void
+    {
+        $tarBuilder = new TarBuilder();
+        $localFile = $this->tempDir . '/somefile.txt';
+        file_put_contents($localFile, 'abc');
+        $tarBuilder->addFile($localFile, 'test.txt');
+
+        $tarBuilder->clear();
+
+        $tarPath = $tarBuilder->buildTarArchive();
+        $this->assertFileExists($tarPath);
+
+        $extractDir = $this->tempDir . '/extractCleared';
+        mkdir($extractDir);
+        $this->extractTar($tarPath, $extractDir);
+
+        $scanned = array_diff(scandir($extractDir), ['.', '..']);
+        $this->assertCount(0, $scanned, 'Expected no files after clear()');
+    }
+
+    /**
+     * Helper function to extract a .tar for verification.
+     */
+    private function extractTar(string $tarPath, string $destination): void
+    {
+        $cmd = sprintf(
+            'tar -xpf %s -C %s 2>&1',
+            escapeshellarg($tarPath),
+            escapeshellarg($destination)
+        );
+
+        exec($cmd, $output, $exitCode);
+        if ($exitCode !== 0) {
+            $errorText = implode("\n", $output);
+            throw new RuntimeException("Failed to extract tar:\n{$errorText}");
+        }
+    }
+
+    /**
+     * Recursively remove directory.
+     */
+    private function removeDirectoryRecursively(string $path): void
+    {
+        if (!is_dir($path)) {
+            return;
+        }
+
+        /** @var RecursiveIteratorIterator<RecursiveDirectoryIterator> $items */
+        $items = new RecursiveIteratorIterator(
+            new RecursiveDirectoryIterator($path, \FilesystemIterator::SKIP_DOTS),
+            RecursiveIteratorIterator::CHILD_FIRST
+        );
+
+        foreach ($items as $item) {
+            if (!$item instanceof SplFileInfo) {
+                continue;
+            }
+            if ($item->isDir()) {
+                rmdir($item->getRealPath());
+            } else {
+                unlink($item->getRealPath());
+            }
+        }
+        rmdir($path);
+    }
+}