diff --git a/src/Service/OpenEMRConnector.php b/src/Service/OpenEMRConnector.php
index 253f1ba..4e82706 100644
--- a/src/Service/OpenEMRConnector.php
+++ b/src/Service/OpenEMRConnector.php
@@ -22,6 +22,11 @@
 
 class OpenEMRConnector
 {
+    // The D modifier makes $ match end-of-string only — without it, "site\n"
+    // would slip past, since $ defaults to "end-of-string OR just before a
+    // trailing newline."
+    private const SITE_PATTERN = '/^[A-Za-z0-9_-]+$/D';
+
     private string $openemrPath = '';
     private string $site = 'default';
     private bool $initialized = false;
@@ -32,37 +37,78 @@ public function initialize(string $openemrPath, string $site = 'default'): void
             return;
         }
 
-        // Site name becomes a filesystem path segment (sites/<site>/sqlconf.php)
-        // and is also written into $_GET. Restrict to a safe character set
-        // before either use to prevent path traversal during bootstrap.
-        if (preg_match('/^[A-Za-z0-9_-]+$/', $site) !== 1) {
+        $this->validateSite($site);
+
+        $this->openemrPath = rtrim($openemrPath, '/');
+        $this->site = $site;
+
+        $globalsPath = $this->resolveGlobalsPath($this->openemrPath);
+
+        $this->prepareCliEnvironment($site);
+
+        // Inline, not extracted: globals.php reads $ignoreAuth and
+        // $sessionAllowWrite during the require and may touch other locals,
+        // so we keep the same local scope as the original implementation.
+        $ignoreAuth = true;
+        $sessionAllowWrite = true;
+        require_once $globalsPath;
+
+        $this->verifyDatabase();
+
+        $this->initialized = true;
+    }
+
+    /**
+     * Validate the --site value.
+     *
+     * Site name becomes a filesystem path segment (sites/<site>/sqlconf.php)
+     * and is also written into $_GET. Restrict to a safe character set
+     * before either use to prevent path traversal during bootstrap.
+     */
+    protected function validateSite(string $site): void
+    {
+        if (preg_match(self::SITE_PATTERN, $site) !== 1) {
             throw new OpenEMRConnectorException(
                 "Invalid --site value; must match [A-Za-z0-9_-]+, got: {$site}"
             );
         }
+    }
 
-        $this->openemrPath = rtrim($openemrPath, '/');
-        $this->site = $site;
-
-        $globalsPath = $this->openemrPath . '/interface/globals.php';
+    /**
+     * Locate interface/globals.php under the given OpenEMR root.
+     *
+     * @return string Absolute path to globals.php (verified to exist).
+     */
+    protected function resolveGlobalsPath(string $openemrPath): string
+    {
+        $globalsPath = rtrim($openemrPath, '/') . '/interface/globals.php';
         if (!file_exists($globalsPath)) {
             throw new OpenEMRConnectorException("OpenEMR globals.php not found at: {$globalsPath}");
         }
 
-        // globals.php reads $_SERVER values during the require; set safe CLI defaults.
+        return $globalsPath;
+    }
+
+    /**
+     * Populate $_SERVER and $_GET so globals.php can be required from a CLI
+     * context. globals.php reads these during the require and dies if they
+     * are missing.
+     */
+    protected function prepareCliEnvironment(string $site): void
+    {
         $_SERVER['HTTP_HOST'] ??= 'localhost';
         $_SERVER['REQUEST_URI'] ??= '/';
         $_SERVER['SCRIPT_NAME'] ??= '/cli.php';
         $_SERVER['SERVER_NAME'] ??= 'localhost';
 
         $_GET['site'] = $site;
+    }
 
-        // Must be set BEFORE the require — globals.php consumes them during inclusion.
-        $ignoreAuth = true;
-        $sessionAllowWrite = true;
-
-        require_once $globalsPath;
-
+    /**
+     * Confirm the OpenEMR database connection came up after bootstrap.
+     */
+    protected function verifyDatabase(): void
+    {
         if (!isset($GLOBALS['dbh']) || $GLOBALS['dbh'] === false) {
             throw new OpenEMRConnectorException(
                 "OpenEMR database connection failed; check sqlconf.php and that MySQL is reachable"
@@ -82,8 +128,6 @@ public function initialize(string $openemrPath, string $site = 'default'): void
                 $e
             );
         }
-
-        $this->initialized = true;
     }
 
     public function isInitialized(): bool
diff --git a/tests/Unit/Service/OpenEMRConnectorTest.php b/tests/Unit/Service/OpenEMRConnectorTest.php
new file mode 100644
index 0000000..e9f91f6
--- /dev/null
+++ b/tests/Unit/Service/OpenEMRConnectorTest.php
@@ -0,0 +1,261 @@
+<?php
+
+/**
+ * Unit tests for OpenEMRConnector.
+ *
+ * initialize() requires a real OpenEMR install on disk, so it is exercised
+ * end-to-end via the smoke task. The pieces it composes (site validation,
+ * globals.php location, CLI env defaults, post-bootstrap DB verification)
+ * are protected helpers; this test reaches them via a subclass that exposes
+ * each one directly.
+ *
+ * @package   OpenCoreEMR\CLI\ManageUsers\Tests
+ * @link      https://opencoreemr.com
+ * @author    Michael A. Smith <michael@opencoreemr.com>
+ * @copyright Copyright (c) 2026 OpenCoreEMR Inc
+ * @license   https://github.com/openCoreEMR/oce-cli-manage-users/blob/main/LICENSE GNU General Public License 3
+ */
+
+declare(strict_types=1);
+
+namespace OpenCoreEMR\CLI\ManageUsers\Tests\Unit\Service;
+
+use OpenCoreEMR\CLI\ManageUsers\Exception\OpenEMRConnectorException;
+use PHPUnit\Framework\Attributes\DataProvider;
+use PHPUnit\Framework\Attributes\Test;
+use PHPUnit\Framework\TestCase;
+
+class OpenEMRConnectorTest extends TestCase
+{
+    private OpenEMRConnectorTestable $connector;
+
+    /** @var array<string, string|null> */
+    private array $serverBackup = [];
+
+    /** @var array<string, mixed> */
+    private array $getBackup = [];
+
+    /** @var list<string> */
+    private array $tempRoots = [];
+
+    private ?bool $hadDbh = null;
+    private mixed $dbhBackup = null;
+
+    protected function setUp(): void
+    {
+        $this->connector = new OpenEMRConnectorTestable();
+
+        foreach (['HTTP_HOST', 'REQUEST_URI', 'SCRIPT_NAME', 'SERVER_NAME'] as $key) {
+            $this->serverBackup[$key] = $_SERVER[$key] ?? null;
+            unset($_SERVER[$key]);
+        }
+        $this->getBackup = $_GET;
+
+        $this->hadDbh = array_key_exists('dbh', $GLOBALS);
+        $this->dbhBackup = $GLOBALS['dbh'] ?? null;
+    }
+
+    protected function tearDown(): void
+    {
+        foreach ($this->serverBackup as $key => $value) {
+            if ($value === null) {
+                unset($_SERVER[$key]);
+            } else {
+                $_SERVER[$key] = $value;
+            }
+        }
+        $_GET = $this->getBackup;
+
+        if ($this->hadDbh) {
+            $GLOBALS['dbh'] = $this->dbhBackup;
+        } else {
+            unset($GLOBALS['dbh']);
+        }
+
+        foreach ($this->tempRoots as $root) {
+            @unlink($root . '/interface/globals.php');
+            @rmdir($root . '/interface');
+            @rmdir($root);
+        }
+        $this->tempRoots = [];
+    }
+
+    /** @return iterable<string, array{string}> */
+    public static function validSites(): iterable
+    {
+        yield 'default' => ['default'];
+        yield 'lowercase letters' => ['clinic'];
+        yield 'mixed case' => ['ClinicA'];
+        yield 'digits' => ['site42'];
+        yield 'underscore' => ['site_one'];
+        yield 'hyphen' => ['site-one'];
+        yield 'all allowed chars' => ['Aa0_-'];
+    }
+
+    #[Test]
+    #[DataProvider('validSites')]
+    public function validateSiteAcceptsSafeNames(string $site): void
+    {
+        $this->expectNotToPerformAssertions();
+        $this->connector->callValidateSite($site);
+    }
+
+    /** @return iterable<string, array{string}> */
+    public static function invalidSites(): iterable
+    {
+        yield 'empty' => [''];
+        yield 'path traversal' => ['../etc'];
+        yield 'forward slash' => ['a/b'];
+        yield 'space' => ['site one'];
+        yield 'dot' => ['site.one'];
+        yield 'null byte' => ["site\0"];
+        yield 'newline' => ["site\n"];
+        yield 'unicode' => ['sité'];
+    }
+
+    #[Test]
+    #[DataProvider('invalidSites')]
+    public function validateSiteRejectsUnsafeNames(string $site): void
+    {
+        $this->expectException(OpenEMRConnectorException::class);
+        $this->expectExceptionMessage('Invalid --site value');
+        $this->connector->callValidateSite($site);
+    }
+
+    #[Test]
+    public function resolveGlobalsPathReturnsPathWhenFileExists(): void
+    {
+        $root = $this->makeFakeOpenemrRoot();
+
+        $resolved = $this->connector->callResolveGlobalsPath($root);
+
+        $this->assertSame($root . '/interface/globals.php', $resolved);
+    }
+
+    #[Test]
+    public function resolveGlobalsPathTrimsTrailingSlash(): void
+    {
+        $root = $this->makeFakeOpenemrRoot();
+
+        $resolved = $this->connector->callResolveGlobalsPath($root . '/');
+
+        $this->assertSame($root . '/interface/globals.php', $resolved);
+    }
+
+    #[Test]
+    public function resolveGlobalsPathThrowsWhenMissing(): void
+    {
+        $this->expectException(OpenEMRConnectorException::class);
+        $this->expectExceptionMessage('OpenEMR globals.php not found');
+        $this->connector->callResolveGlobalsPath(sys_get_temp_dir() . '/no-such-openemr-' . uniqid());
+    }
+
+    #[Test]
+    public function prepareCliEnvironmentSetsDefaults(): void
+    {
+        $this->connector->callPrepareCliEnvironment('default');
+
+        $this->assertSame('localhost', $_SERVER['HTTP_HOST']);
+        $this->assertSame('/', $_SERVER['REQUEST_URI']);
+        $this->assertSame('/cli.php', $_SERVER['SCRIPT_NAME']);
+        $this->assertSame('localhost', $_SERVER['SERVER_NAME']);
+        $this->assertSame('default', $_GET['site']);
+    }
+
+    #[Test]
+    public function prepareCliEnvironmentDoesNotOverrideExistingServerVars(): void
+    {
+        $_SERVER['HTTP_HOST'] = 'preset.example';
+        $_SERVER['REQUEST_URI'] = '/preset';
+        $_SERVER['SCRIPT_NAME'] = '/preset.php';
+        $_SERVER['SERVER_NAME'] = 'preset.example';
+
+        $this->connector->callPrepareCliEnvironment('clinic');
+
+        $this->assertSame('preset.example', $_SERVER['HTTP_HOST']);
+        $this->assertSame('/preset', $_SERVER['REQUEST_URI']);
+        $this->assertSame('/preset.php', $_SERVER['SCRIPT_NAME']);
+        $this->assertSame('preset.example', $_SERVER['SERVER_NAME']);
+    }
+
+    #[Test]
+    public function prepareCliEnvironmentAlwaysOverwritesGetSite(): void
+    {
+        $_GET['site'] = 'stale';
+
+        $this->connector->callPrepareCliEnvironment('clinic');
+
+        $this->assertSame('clinic', $_GET['site']);
+    }
+
+    #[Test]
+    public function verifyDatabaseThrowsWhenDbhMissing(): void
+    {
+        unset($GLOBALS['dbh']);
+
+        $this->expectException(OpenEMRConnectorException::class);
+        $this->expectExceptionMessage('OpenEMR database connection failed');
+        $this->connector->callVerifyDatabase();
+    }
+
+    #[Test]
+    public function verifyDatabaseThrowsWhenDbhFalse(): void
+    {
+        $GLOBALS['dbh'] = false;
+
+        $this->expectException(OpenEMRConnectorException::class);
+        $this->expectExceptionMessage('OpenEMR database connection failed');
+        $this->connector->callVerifyDatabase();
+    }
+
+    #[Test]
+    public function verifyDatabaseThrowsWhenSqlQueryMissing(): void
+    {
+        if (function_exists('sqlQuery')) {
+            $this->markTestSkipped('sqlQuery() is defined in this process; cannot test missing-function branch.');
+        }
+
+        $GLOBALS['dbh'] = new \stdClass();
+
+        $this->expectException(OpenEMRConnectorException::class);
+        $this->expectExceptionMessage('OpenEMR sql functions not loaded after bootstrap');
+        $this->connector->callVerifyDatabase();
+    }
+
+    #[Test]
+    public function freshConnectorIsNotInitialized(): void
+    {
+        $this->assertFalse($this->connector->isInitialized());
+        $this->assertSame('', $this->connector->getOpenEMRPath());
+        $this->assertSame('default', $this->connector->getSite());
+    }
+
+    #[Test]
+    public function initializeIsIdempotentAfterPriorSuccess(): void
+    {
+        // Simulate a prior successful bootstrap by reaching in via Reflection
+        // (the real path requires a live OpenEMR, which unit tests can't
+        // provide). A second initialize() call must short-circuit; passing a
+        // bogus path here proves it never reaches resolveGlobalsPath.
+        $reflection = new \ReflectionClass(\OpenCoreEMR\CLI\ManageUsers\Service\OpenEMRConnector::class);
+        $reflection->getProperty('openemrPath')->setValue($this->connector, '/already/booted');
+        $reflection->getProperty('site')->setValue($this->connector, 'clinic');
+        $reflection->getProperty('initialized')->setValue($this->connector, true);
+
+        $this->connector->initialize('/no/such/openemr', 'whatever');
+
+        $this->assertTrue($this->connector->isInitialized());
+        $this->assertSame('/already/booted', $this->connector->getOpenEMRPath());
+        $this->assertSame('clinic', $this->connector->getSite());
+    }
+
+    private function makeFakeOpenemrRoot(): string
+    {
+        $root = sys_get_temp_dir() . '/oce-cli-manage-users-test-' . uniqid();
+        mkdir($root . '/interface', 0700, true);
+        file_put_contents($root . '/interface/globals.php', "<?php\n");
+        $this->tempRoots[] = $root;
+
+        return $root;
+    }
+}
diff --git a/tests/Unit/Service/OpenEMRConnectorTestable.php b/tests/Unit/Service/OpenEMRConnectorTestable.php
new file mode 100644
index 0000000..6b2fe63
--- /dev/null
+++ b/tests/Unit/Service/OpenEMRConnectorTestable.php
@@ -0,0 +1,43 @@
+<?php
+
+/**
+ * Test-only subclass that promotes OpenEMRConnector's protected helpers to
+ * public so tests can call them without Reflection. Each pass-through is
+ * named call*() to make it obvious at the call site that this is a test
+ * shim, not part of the production API.
+ *
+ * @package   OpenCoreEMR\CLI\ManageUsers\Tests
+ * @link      https://opencoreemr.com
+ * @author    Michael A. Smith <michael@opencoreemr.com>
+ * @copyright Copyright (c) 2026 OpenCoreEMR Inc
+ * @license   https://github.com/openCoreEMR/oce-cli-manage-users/blob/main/LICENSE GNU General Public License 3
+ */
+
+declare(strict_types=1);
+
+namespace OpenCoreEMR\CLI\ManageUsers\Tests\Unit\Service;
+
+use OpenCoreEMR\CLI\ManageUsers\Service\OpenEMRConnector;
+
+class OpenEMRConnectorTestable extends OpenEMRConnector
+{
+    public function callValidateSite(string $site): void
+    {
+        $this->validateSite($site);
+    }
+
+    public function callResolveGlobalsPath(string $openemrPath): string
+    {
+        return $this->resolveGlobalsPath($openemrPath);
+    }
+
+    public function callPrepareCliEnvironment(string $site): void
+    {
+        $this->prepareCliEnvironment($site);
+    }
+
+    public function callVerifyDatabase(): void
+    {
+        $this->verifyDatabase();
+    }
+}