diff --git a/phpunit.xml b/phpunit.xml
new file mode 100644
index 0000000..4f6e451
--- /dev/null
+++ b/phpunit.xml
@@ -0,0 +1,17 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--
+Copyright (C) 2026 Moko Consulting <hello@mokoconsulting.tech>
+SPDX-License-Identifier: GPL-3.0-or-later
+-->
+<phpunit xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:noNamespaceSchemaLocation="vendor/phpunit/phpunit/phpunit.xsd"
+         bootstrap="vendor/autoload.php"
+         colors="true"
+         failOnRisky="true"
+         failOnWarning="true">
+    <testsuites>
+        <testsuite name="Unit">
+            <directory>tests/Unit</directory>
+        </testsuite>
+    </testsuites>
+</phpunit>
diff --git a/tests/Unit/VersionBumpTest.php b/tests/Unit/VersionBumpTest.php
new file mode 100644
index 0000000..f6dd408
--- /dev/null
+++ b/tests/Unit/VersionBumpTest.php
@@ -0,0 +1,164 @@
+<?php
+
+/* Copyright (C) 2026 Moko Consulting <hello@mokoconsulting.tech>
+ * SPDX-License-Identifier: GPL-3.0-or-later
+ */
+
+declare(strict_types=1);
+
+namespace MokoStandards\Tests\Unit;
+
+use PHPUnit\Framework\TestCase;
+
+/**
+ * Tests for cli/version_bump.php
+ */
+class VersionBumpTest extends TestCase
+{
+    private string $tmpDir;
+    private string $script;
+
+    protected function setUp(): void
+    {
+        $this->tmpDir = sys_get_temp_dir() . '/moko-test-' . uniqid();
+        mkdir($this->tmpDir, 0755, true);
+        $this->script = dirname(__DIR__, 2) . '/cli/version_bump.php';
+    }
+
+    protected function tearDown(): void
+    {
+        $this->rmdir($this->tmpDir);
+    }
+
+    public function testPatchBump(): void
+    {
+        $this->writeReadme('01.02.03');
+        $output = $this->execute();
+        $this->assertStringContainsString('01.02.04', $output);
+        $this->assertReadmeVersion('01.02.04');
+    }
+
+    public function testPatchBumpRollover(): void
+    {
+        $this->writeReadme('01.02.99');
+        $this->execute();
+        $this->assertReadmeVersion('01.03.00');
+    }
+
+    public function testMinorBump(): void
+    {
+        $this->writeReadme('01.02.03');
+        $this->execute(['--minor']);
+        $this->assertReadmeVersion('01.03.00');
+    }
+
+    public function testMajorBump(): void
+    {
+        $this->writeReadme('01.02.03');
+        $this->execute(['--major']);
+        $this->assertReadmeVersion('02.00.00');
+    }
+
+    public function testBumpsFromHtmlComment(): void
+    {
+        file_put_contents(
+            "{$this->tmpDir}/README.md",
+            "<!-- VERSION: 03.05.01 -->\nSome content\n"
+        );
+
+        $this->execute();
+        $content = file_get_contents("{$this->tmpDir}/README.md");
+        $this->assertStringContainsString('03.05.02', $content);
+        $this->assertStringContainsString('Some content', $content);
+    }
+
+    public function testBumpsWhenXmlHasSuffix(): void
+    {
+        $this->writeReadme('01.00.00');
+        mkdir("{$this->tmpDir}/src", 0755, true);
+        file_put_contents(
+            "{$this->tmpDir}/src/test.xml",
+            '<extension type="component">'
+            . '<version>01.00.00-dev</version></extension>'
+        );
+
+        $output = $this->execute();
+        $this->assertStringContainsString('01.00.01', $output);
+    }
+
+    public function testFailsWithNoVersion(): void
+    {
+        file_put_contents(
+            "{$this->tmpDir}/README.md",
+            "# No version\n"
+        );
+
+        $code = 0;
+        $this->execute([], $code);
+        $this->assertSame(1, $code);
+    }
+
+    private function writeReadme(string $version): void
+    {
+        file_put_contents(
+            "{$this->tmpDir}/README.md",
+            "<!-- VERSION: {$version} -->\n"
+        );
+    }
+
+    private function assertReadmeVersion(string $expected): void
+    {
+        $content = file_get_contents("{$this->tmpDir}/README.md");
+        $this->assertMatchesRegularExpression(
+            '/VERSION:\s*' . preg_quote($expected, '/') . '/',
+            $content
+        );
+    }
+
+    /**
+     * @param string[] $extraArgs
+     */
+    private function execute(
+        array $extraArgs = [],
+        int &$exitCode = 0
+    ): string {
+        $cmd = ['php', $this->script, '--path', $this->tmpDir];
+        $cmd = array_merge($cmd, $extraArgs);
+
+        $descriptors = [
+            1 => ['pipe', 'w'],
+            2 => ['pipe', 'w'],
+        ];
+
+        $proc = proc_open($cmd, $descriptors, $pipes);
+        $stdout = stream_get_contents($pipes[1]);
+        fclose($pipes[1]);
+        fclose($pipes[2]);
+        $exitCode = proc_close($proc);
+
+        return $stdout ?: '';
+    }
+
+    private function rmdir(string $dir): void
+    {
+        if (!is_dir($dir)) {
+            return;
+        }
+
+        $iter = new \RecursiveIteratorIterator(
+            new \RecursiveDirectoryIterator(
+                $dir,
+                \FilesystemIterator::SKIP_DOTS
+            ),
+            \RecursiveIteratorIterator::CHILD_FIRST
+        );
+
+        foreach ($iter as $file) {
+            $file->isDir()
+                ? rmdir($file->getPathname())
+                : unlink($file->getPathname());
+        }
+
+        rmdir($dir);
+    }
+}
diff --git a/tests/Unit/VersionReadTest.php b/tests/Unit/VersionReadTest.php
new file mode 100644
index 0000000..9715c29
--- /dev/null
+++ b/tests/Unit/VersionReadTest.php
@@ -0,0 +1,133 @@
+<?php
+
+/* Copyright (C) 2026 Moko Consulting <hello@mokoconsulting.tech>
+ * SPDX-License-Identifier: GPL-3.0-or-later
+ */
+
+declare(strict_types=1);
+
+namespace MokoStandards\Tests\Unit;
+
+use PHPUnit\Framework\TestCase;
+
+/**
+ * Tests for cli/version_read.php
+ */
+class VersionReadTest extends TestCase
+{
+    private string $tmpDir;
+    private string $script;
+
+    protected function setUp(): void
+    {
+        $this->tmpDir = sys_get_temp_dir() . '/moko-test-' . uniqid();
+        mkdir($this->tmpDir, 0755, true);
+        $this->script = dirname(__DIR__, 2) . '/cli/version_read.php';
+    }
+
+    protected function tearDown(): void
+    {
+        $this->rmdir($this->tmpDir);
+    }
+
+    public function testReadsVersionFromReadme(): void
+    {
+        file_put_contents(
+            "{$this->tmpDir}/README.md",
+            "# Test\n<!-- VERSION: 02.03.04 -->\n"
+        );
+
+        $this->assertSame('02.03.04', trim($this->runScript()));
+    }
+
+    public function testReadsVersionFromXmlManifest(): void
+    {
+        mkdir("{$this->tmpDir}/src", 0755, true);
+        file_put_contents(
+            "{$this->tmpDir}/src/test.xml",
+            '<extension type="component">'
+            . '<version>05.01.00</version></extension>'
+        );
+
+        $this->assertSame('05.01.00', trim($this->runScript()));
+    }
+
+    public function testStripsStabilitySuffixFromXml(): void
+    {
+        mkdir("{$this->tmpDir}/src", 0755, true);
+        file_put_contents(
+            "{$this->tmpDir}/src/test.xml",
+            '<extension type="component">'
+            . '<version>01.00.00-dev</version></extension>'
+        );
+
+        $this->assertSame('01.00.00', trim($this->runScript()));
+    }
+
+    public function testReturnsHigherOfReadmeAndManifest(): void
+    {
+        file_put_contents(
+            "{$this->tmpDir}/README.md",
+            "<!-- VERSION: 01.02.00 -->\n"
+        );
+        mkdir("{$this->tmpDir}/src", 0755, true);
+        file_put_contents(
+            "{$this->tmpDir}/src/test.xml",
+            '<extension type="component">'
+            . '<version>01.03.00</version></extension>'
+        );
+
+        $this->assertSame('01.03.00', trim($this->runScript()));
+    }
+
+    public function testExitsNonZeroWhenNoVersion(): void
+    {
+        file_put_contents(
+            "{$this->tmpDir}/README.md",
+            "# No version here\n"
+        );
+
+        $code = 0;
+        $this->runScript($code);
+        $this->assertSame(1, $code);
+    }
+
+    private function runScript(int &$exitCode = 0): string
+    {
+        $proc = proc_open(
+            ['php', $this->script, '--path', $this->tmpDir],
+            [1 => ['pipe', 'w'], 2 => ['pipe', 'w']],
+            $pipes
+        );
+
+        $stdout = stream_get_contents($pipes[1]);
+        fclose($pipes[1]);
+        fclose($pipes[2]);
+        $exitCode = proc_close($proc);
+
+        return $stdout ?: '';
+    }
+
+    private function rmdir(string $dir): void
+    {
+        if (!is_dir($dir)) {
+            return;
+        }
+
+        $iter = new \RecursiveIteratorIterator(
+            new \RecursiveDirectoryIterator(
+                $dir,
+                \FilesystemIterator::SKIP_DOTS
+            ),
+            \RecursiveIteratorIterator::CHILD_FIRST
+        );
+
+        foreach ($iter as $file) {
+            $file->isDir()
+                ? rmdir($file->getPathname())
+                : unlink($file->getPathname());
+        }
+
+        rmdir($dir);
+    }
+}