diff --git a/phpunit.xml.dist b/phpunit.xml.dist
index a6f2dc9..d81e94a 100644
--- a/phpunit.xml.dist
+++ b/phpunit.xml.dist
@@ -6,7 +6,6 @@
          cacheDirectory=".phpunit.cache"
          executionOrder="depends,defects"
          requireCoverageMetadata="true"
-         beStrictAboutCoverageMetadata="true"
          beStrictAboutOutputDuringTests="true"
          failOnRisky="true"
          failOnWarning="true">
diff --git a/src/DependencyResolver/Package.php b/src/DependencyResolver/Package.php
index 7fabaeb..d6c1151 100644
--- a/src/DependencyResolver/Package.php
+++ b/src/DependencyResolver/Package.php
@@ -16,7 +16,7 @@ final class Package
     public const TYPE_PHP_MODULE     = 'php-ext';
     public const TYPE_ZEND_EXTENSION = 'php-ext-zend';
 
-    private function __construct(
+    public function __construct(
         public readonly string $name,
         public readonly string $version,
         public readonly string|null $downloadUrl,
diff --git a/src/DependencyResolver/UnableToResolveRequirement.php b/src/DependencyResolver/UnableToResolveRequirement.php
index 3ab76ad..1815eef 100644
--- a/src/DependencyResolver/UnableToResolveRequirement.php
+++ b/src/DependencyResolver/UnableToResolveRequirement.php
@@ -23,10 +23,10 @@ class UnableToResolveRequirement extends RuntimeException
     public static function toPhpOrZendExtension(PackageInterface $locatedComposerPackage, string $requiredPackageName, string|null $requiredVersion): self
     {
         return new self(sprintf(
-            'Package %s was not of type php-ext or php-ext-zend (requested %s%s)',
+            'Package %s was not of type php-ext or php-ext-zend (requested %s%s).',
             $locatedComposerPackage->getName(),
             $requiredPackageName,
-            $requiredVersion !== null ? sprintf(' for version %s.', $requiredVersion) : '.',
+            $requiredVersion !== null ? sprintf(' for version %s', $requiredVersion) : '',
         ));
     }
 }
diff --git a/test/assets/test-zip.zip b/test/assets/test-zip.zip
new file mode 100644
index 0000000..451d018
Binary files /dev/null and b/test/assets/test-zip.zip differ
diff --git a/test/unit/DependencyResolver/UnableToResolveRequirementTest.php b/test/unit/DependencyResolver/UnableToResolveRequirementTest.php
new file mode 100644
index 0000000..e79b3ae
--- /dev/null
+++ b/test/unit/DependencyResolver/UnableToResolveRequirementTest.php
@@ -0,0 +1,48 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Php\PieUnitTest\DependencyResolver;
+
+use Composer\Package\PackageInterface;
+use Php\Pie\DependencyResolver\UnableToResolveRequirement;
+use PHPUnit\Framework\Attributes\CoversClass;
+use PHPUnit\Framework\TestCase;
+
+#[CoversClass(UnableToResolveRequirement::class)]
+final class UnableToResolveRequirementTest extends TestCase
+{
+    public function testToPhpOrZendExtensionWithVersion(): void
+    {
+        $package = $this->createMock(PackageInterface::class);
+        $package->method('getName')->willReturn('baz/bat');
+
+        $exception = UnableToResolveRequirement::toPhpOrZendExtension($package, 'foo/bar', '^1.2');
+
+        self::assertSame('Package baz/bat was not of type php-ext or php-ext-zend (requested foo/bar for version ^1.2).', $exception->getMessage());
+    }
+
+    public function testToPhpOrZendExtensionWithoutVersion(): void
+    {
+        $package = $this->createMock(PackageInterface::class);
+        $package->method('getName')->willReturn('baz/bat');
+
+        $exception = UnableToResolveRequirement::toPhpOrZendExtension($package, 'foo/bar', null);
+
+        self::assertSame('Package baz/bat was not of type php-ext or php-ext-zend (requested foo/bar).', $exception->getMessage());
+    }
+
+    public function testFromRequirementWithVersion(): void
+    {
+        $exception = UnableToResolveRequirement::fromRequirement('foo/bar', '^1.2');
+
+        self::assertSame('Unable to find an installable package foo/bar for version ^1.2.', $exception->getMessage());
+    }
+
+    public function testFromRequirementWithoutVersion(): void
+    {
+        $exception = UnableToResolveRequirement::fromRequirement('foo/bar', null);
+
+        self::assertSame('Unable to find an installable package foo/bar.', $exception->getMessage());
+    }
+}
diff --git a/test/unit/Downloading/AddAuthenticationHeaderTest.php b/test/unit/Downloading/AddAuthenticationHeaderTest.php
new file mode 100644
index 0000000..f24b0ee
--- /dev/null
+++ b/test/unit/Downloading/AddAuthenticationHeaderTest.php
@@ -0,0 +1,56 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Php\PieUnitTest\Downloading;
+
+use Composer\Util\AuthHelper;
+use GuzzleHttp\Psr7\Request;
+use Php\Pie\DependencyResolver\Package;
+use Php\Pie\Downloading\AddAuthenticationHeader;
+use PHPUnit\Framework\Attributes\CoversClass;
+use PHPUnit\Framework\TestCase;
+use RuntimeException;
+
+use function uniqid;
+
+#[CoversClass(AddAuthenticationHeader::class)]
+final class AddAuthenticationHeaderTest extends TestCase
+{
+    public function testAuthorizationHeaderIsAdded(): void
+    {
+        $downloadUrl = 'http://test-uri/' . uniqid('path', true);
+
+        $request = new Request('GET', $downloadUrl);
+
+        $authHelper = $this->createMock(AuthHelper::class);
+        $authHelper->expects(self::once())
+            ->method('addAuthenticationHeader')
+            ->with([], 'github.com', $downloadUrl)
+            ->willReturn(['Authorization: whatever ABC123']);
+
+        $requestWithAuthHeader = (new AddAuthenticationHeader())->withAuthHeaderFromComposer(
+            $request,
+            new Package('foo/bar', '1.2.3', $downloadUrl),
+            $authHelper,
+        );
+
+        self::assertSame('whatever ABC123', $requestWithAuthHeader->getHeaderLine('Authorization'));
+    }
+
+    public function testExceptionIsThrownWhenPackageDoesNotHaveDownloadUrl(): void
+    {
+        $downloadUrl = 'http://test-uri/' . uniqid('path', true);
+
+        $request = new Request('GET', $downloadUrl);
+
+        $authHelper = $this->createMock(AuthHelper::class);
+
+        $addAuthenticationHeader = new AddAuthenticationHeader();
+        $package                 = new Package('foo/bar', '1.2.3', null);
+
+        $this->expectException(RuntimeException::class);
+        $this->expectExceptionMessage('The package foo/bar does not have a download URL');
+        $addAuthenticationHeader->withAuthHeaderFromComposer($request, $package, $authHelper);
+    }
+}
diff --git a/test/unit/Downloading/DownloadZipTest.php b/test/unit/Downloading/DownloadZipTest.php
new file mode 100644
index 0000000..a7e0473
--- /dev/null
+++ b/test/unit/Downloading/DownloadZipTest.php
@@ -0,0 +1,54 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Php\PieUnitTest\Downloading;
+
+use GuzzleHttp\Client;
+use GuzzleHttp\Handler\MockHandler;
+use GuzzleHttp\HandlerStack;
+use GuzzleHttp\Psr7\Request;
+use GuzzleHttp\Psr7\Response;
+use Php\Pie\Downloading\DownloadZip;
+use PHPUnit\Framework\Attributes\CoversClass;
+use PHPUnit\Framework\TestCase;
+
+use function file_get_contents;
+use function mkdir;
+use function strlen;
+use function sys_get_temp_dir;
+use function uniqid;
+
+use const DIRECTORY_SEPARATOR;
+
+#[CoversClass(DownloadZip::class)]
+final class DownloadZipTest extends TestCase
+{
+    public function testDownloadZipAndReturnLocalPath(): void
+    {
+        $fakeZipContent = uniqid('fakeZipContent', true);
+
+        $mockHandler = new MockHandler([
+            new Response(
+                200,
+                [
+                    'Content-type' => 'application/octet-stream',
+                    'Content-length' => (string) (strlen($fakeZipContent)),
+                ],
+                $fakeZipContent,
+            ),
+        ]);
+
+        $guzzleMockClient = new Client(['handler' => HandlerStack::create($mockHandler)]);
+
+        $localPath = sys_get_temp_dir() . DIRECTORY_SEPARATOR . uniqid('pie_test_', true);
+        mkdir($localPath, 0777, true);
+        $downloadedZipFile = (new DownloadZip($guzzleMockClient))
+            ->downloadZipAndReturnLocalPath(
+                new Request('GET', 'http://test-uri/'),
+                $localPath,
+            );
+
+        self::assertSame($fakeZipContent, file_get_contents($downloadedZipFile));
+    }
+}
diff --git a/test/unit/Downloading/DownloadedPackageTest.php b/test/unit/Downloading/DownloadedPackageTest.php
new file mode 100644
index 0000000..2d029c8
--- /dev/null
+++ b/test/unit/Downloading/DownloadedPackageTest.php
@@ -0,0 +1,28 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Php\PieUnitTest\Downloading;
+
+use Php\Pie\DependencyResolver\Package;
+use Php\Pie\Downloading\DownloadedPackage;
+use PHPUnit\Framework\Attributes\CoversClass;
+use PHPUnit\Framework\TestCase;
+
+use function uniqid;
+
+#[CoversClass(DownloadedPackage::class)]
+final class DownloadedPackageTest extends TestCase
+{
+    public function testFromPackageAndExtractedPath(): void
+    {
+        $package = new Package('foo/bar', '1.2.3', null);
+
+        $extractedSourcePath = uniqid('/path/to/downloaded/package', true);
+
+        $downloadedPackage = DownloadedPackage::fromPackageAndExtractedPath($package, $extractedSourcePath);
+
+        self::assertSame($extractedSourcePath, $downloadedPackage->extractedSourcePath);
+        self::assertSame($package, $downloadedPackage->package);
+    }
+}
diff --git a/test/unit/Downloading/ExtractZipTest.php b/test/unit/Downloading/ExtractZipTest.php
new file mode 100644
index 0000000..f6d7149
--- /dev/null
+++ b/test/unit/Downloading/ExtractZipTest.php
@@ -0,0 +1,48 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Php\PieUnitTest\Downloading;
+
+use Php\Pie\Downloading\ExtractZip;
+use PHPUnit\Framework\Attributes\CoversClass;
+use PHPUnit\Framework\TestCase;
+use RuntimeException;
+use ZipArchive;
+
+use function file_get_contents;
+use function mkdir;
+use function sprintf;
+use function sys_get_temp_dir;
+use function uniqid;
+
+use const DIRECTORY_SEPARATOR;
+
+/** @covers \Php\Pie\Downloading\ExtractZip */
+#[CoversClass(ExtractZip::class)]
+final class ExtractZipTest extends TestCase
+{
+    public function testZipFileCanBeExtracted(): void
+    {
+        $localPath = sys_get_temp_dir() . DIRECTORY_SEPARATOR . uniqid('pie_test_', true);
+        mkdir($localPath, 0777, true);
+
+        $extr = new ExtractZip();
+
+        $extractedPath = $extr->to(__DIR__ . '/../../assets/test-zip.zip', $localPath);
+
+        // The test-zip.zip should contain a deterministic file content for this:
+        self::assertSame('Hello there! Test UUID b925c59b-3e6f-4e45-8029-19431df18de4', file_get_contents($extractedPath . DIRECTORY_SEPARATOR . 'test-file.txt'));
+    }
+
+    public function testFailureToExtractZipWithInvalidZip(): void
+    {
+        $localPath = sys_get_temp_dir() . DIRECTORY_SEPARATOR . uniqid('pie_test_DO_NOT_EXIST_', true);
+
+        $extr = new ExtractZip();
+
+        $this->expectException(RuntimeException::class);
+        $this->expectExceptionMessage(sprintf('Could not open ZIP [%d]: %s', ZipArchive::ER_NOZIP, __FILE__));
+        $extr->to(__FILE__, $localPath);
+    }
+}
diff --git a/test/unit/TargetPhp/PhpBinaryPathTest.php b/test/unit/TargetPhp/PhpBinaryPathTest.php
index a18bdb5..212a195 100644
--- a/test/unit/TargetPhp/PhpBinaryPathTest.php
+++ b/test/unit/TargetPhp/PhpBinaryPathTest.php
@@ -7,8 +7,12 @@ namespace Php\PieUnitTest\TargetPhp;
 use Php\Pie\TargetPhp\PhpBinaryPath;
 use PHPUnit\Framework\Attributes\CoversClass;
 use PHPUnit\Framework\TestCase;
+use Symfony\Component\Process\Process;
 
+use function file_exists;
+use function is_executable;
 use function sprintf;
+use function trim;
 
 use const PHP_MAJOR_VERSION;
 use const PHP_MINOR_VERSION;
@@ -24,4 +28,26 @@ final class PhpBinaryPathTest extends TestCase
             PhpBinaryPath::fromCurrentProcess()->version(),
         );
     }
+
+    public function testFromPhpConfigExecutable(): void
+    {
+        $process             = (new Process(['which', 'php-config']));
+        $exitCode            = $process->run();
+        $phpConfigExecutable = trim($process->getOutput());
+
+        if ($exitCode !== 0 || ! file_exists($phpConfigExecutable) || ! is_executable($phpConfigExecutable)) {
+            self::markTestSkipped('Needs php-config in path to run this test');
+        }
+
+        $phpBinary = PhpBinaryPath::fromPhpConfigExecutable($phpConfigExecutable);
+
+        // NOTE: this makes an assumption that the `php-config` in path is the same as the version being executed
+        // In most cases, this will be the cases (e.g. in CI, running locally), but if you're trying to test this and
+        // the versions are not matching, that's probably why.
+        // @todo improve this assertion in future, if it becomes problematic
+        self::assertSame(
+            sprintf('%s.%s.%s', PHP_MAJOR_VERSION, PHP_MINOR_VERSION, PHP_RELEASE_VERSION),
+            $phpBinary->version(),
+        );
+    }
 }
diff --git a/test/unit/TargetPhp/ResolveTargetPhpToPlatformRepositoryTest.php b/test/unit/TargetPhp/ResolveTargetPhpToPlatformRepositoryTest.php
new file mode 100644
index 0000000..70b80a7
--- /dev/null
+++ b/test/unit/TargetPhp/ResolveTargetPhpToPlatformRepositoryTest.php
@@ -0,0 +1,41 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Php\PieUnitTest\TargetPhp;
+
+use Composer\Package\BasePackage;
+use Php\Pie\TargetPhp\PhpBinaryPath;
+use Php\Pie\TargetPhp\ResolveTargetPhpToPlatformRepository;
+use PHPUnit\Framework\Attributes\CoversClass;
+use PHPUnit\Framework\TestCase;
+
+use function array_filter;
+use function array_key_first;
+use function assert;
+use function count;
+
+#[CoversClass(ResolveTargetPhpToPlatformRepository::class)]
+final class ResolveTargetPhpToPlatformRepositoryTest extends TestCase
+{
+    public function testPlatformRepositoryIsReturned(): void
+    {
+        $php = PhpBinaryPath::fromCurrentProcess();
+
+        $platformRepository = (new ResolveTargetPhpToPlatformRepository())($php);
+
+        $phpPackages = array_filter(
+            $platformRepository->getPackages(),
+            static function (BasePackage $package): bool {
+                return $package->getPrettyName() === 'php';
+            },
+        );
+
+        self::assertCount(1, $phpPackages);
+        assert(count($phpPackages) > 0);
+
+        $phpPackage = $phpPackages[array_key_first($phpPackages)];
+
+        self::assertSame($php->version(), $phpPackage->getPrettyVersion());
+    }
+}