diff --git a/.github/workflows/phpunit.yml b/.github/workflows/phpunit.yml
index e3e6101e..9bbcd040 100644
--- a/.github/workflows/phpunit.yml
+++ b/.github/workflows/phpunit.yml
@@ -65,5 +65,12 @@ jobs:
               if: ${{ matrix.dependencies == 'locked' }}
               run: "composer install --no-interaction --no-progress --no-suggest"
 
+            - name: "Compile PHAR"
+              run: |
+                php -d phar.readonly=0 vendor/bin/phing phar-build
+                # We re-run 'composer install' here as phing runs 'composer install --no-dev'.
+                # Using 'install' (not 'update' with flags) here is correct as the previous update re-wrote wrote the lock file.
+                composer --no-interaction install --no-progress
+
             - name: "Tests"
               run: "vendor/bin/phpunit --coverage-clover=clover.xml --coverage-text"
diff --git a/test/ComposerRequireCheckerTest/PharTest.php b/test/ComposerRequireCheckerTest/PharTest.php
new file mode 100644
index 00000000..52751ecc
--- /dev/null
+++ b/test/ComposerRequireCheckerTest/PharTest.php
@@ -0,0 +1,96 @@
+<?php
+
+declare(strict_types=1);
+
+namespace ComposerRequireCheckerTest;
+
+use PHPUnit\Framework\TestCase;
+
+use function chdir;
+use function dirname;
+use function escapeshellarg;
+use function exec;
+use function getcwd;
+use function implode;
+use function realpath;
+use function sprintf;
+
+use const DIRECTORY_SEPARATOR;
+use const PHP_BINARY;
+
+final class PharTest extends TestCase
+{
+    private string $bin;
+    private string $oldWorkingDirectory;
+
+    protected function setUp(): void
+    {
+        $phar = realpath(dirname(__DIR__, 2) . DIRECTORY_SEPARATOR . 'build' . DIRECTORY_SEPARATOR . 'composer-require-checker.phar');
+
+        if ($phar === false) {
+            $this->markTestSkipped('Compiled PHAR not found');
+        }
+
+        $this->oldWorkingDirectory = getcwd();
+        $this->bin                 = PHP_BINARY . ' ' . escapeshellarg($phar);
+    }
+
+    protected function tearDown(): void
+    {
+        if ($this->oldWorkingDirectory === getcwd()) {
+            return;
+        }
+
+        chdir($this->oldWorkingDirectory);
+    }
+
+    public function testVersion(): void
+    {
+        $command = $this->bin . ' --version';
+        exec($command, $output, $return);
+        $this->assertStringContainsString('ComposerRequireChecker', implode("\n", $output));
+        $this->assertSame(0, $return);
+    }
+
+    public function testSuccess(): void
+    {
+        exec($this->bin, $output, $return);
+        $this->assertSame(0, $return);
+    }
+
+    public function testUnknownSymbols(): void
+    {
+        $path = __DIR__ . '/../fixtures/unknownSymbols/composer.json';
+        exec(sprintf('%s check %s 2>&1', $this->bin, $path), $output, $return);
+        $this->assertStringContainsString('The following 6 unknown symbols were found', implode("\n", $output));
+        $this->assertNotEquals(0, $return);
+    }
+
+    public function testInvalidConfiguration(): void
+    {
+        $path = __DIR__ . '/../fixtures/validJson.json';
+        exec(sprintf('%s check %s 2>&1', $this->bin, $path), $output, $return);
+        $this->assertStringContainsString('dependencies have not been installed', implode("\n", $output));
+        $this->assertNotEquals(0, $return);
+    }
+
+    public function testDefaultConfiguration(): void
+    {
+        chdir(__DIR__ . '/../fixtures/defaultConfigPath');
+        exec(sprintf('%s check 2>&1', $this->bin), $output, $return);
+        $output = implode("\n", $output);
+
+        $this->assertMatchesRegularExpression('/The following [12] unknown symbols were found/', $output);
+        $this->assertMatchesRegularExpression('/Composer\\\\InstalledVersions/', $output);
+        $this->assertNotEquals(0, $return);
+    }
+
+    public function testMissingCustomConfiguration(): void
+    {
+        chdir(__DIR__ . '/../fixtures/noUnknownComposerSymbol');
+        exec(sprintf('%s check --config-file=%s 2>&1', $this->bin, 'no-such-file'), $output, $return);
+
+        $this->assertStringContainsString('Configuration file [no-such-file] does not exist.', implode("\n", $output));
+        $this->assertNotEquals(0, $return);
+    }
+}