diff --git a/modules/helpdesk/tests/Module/Helpdesk/Service/BcODataGatewayTest.php b/modules/helpdesk/tests/Module/Helpdesk/Service/BcODataGatewayTest.php
index f94c3fc..1fda158 100644
--- a/modules/helpdesk/tests/Module/Helpdesk/Service/BcODataGatewayTest.php
+++ b/modules/helpdesk/tests/Module/Helpdesk/Service/BcODataGatewayTest.php
@@ -314,4 +314,102 @@ class BcODataGatewayTest extends TestCase
         $results = $gateway->getTicketsForControlling('10610');
         $this->assertSame([], $results);
     }
+
+    // ── Meetings: empty / whitespace / not-configured ──────────────
+
+    public function testGetMeetingsForCustomerReturnsEmptyForEmptyNo(): void
+    {
+        $gateway = $this->createGatewayWithSettings();
+        $results = $gateway->getMeetingsForCustomer('');
+        $this->assertSame([], $results);
+    }
+
+    public function testGetMeetingsForCustomerReturnsEmptyForWhitespace(): void
+    {
+        $gateway = $this->createGatewayWithSettings();
+        $results = $gateway->getMeetingsForCustomer('   ');
+        $this->assertSame([], $results);
+    }
+
+    public function testGetMeetingsForCustomerReturnsEmptyWhenNotConfigured(): void
+    {
+        $gateway = $this->createGatewayWithSettings(false);
+        $results = $gateway->getMeetingsForCustomer('10610');
+        $this->assertSame([], $results);
+    }
+
+    // ── OData injection rejection on customerNo methods ────────────
+
+    public function testGetMeetingsForCustomerRejectsODataInjection(): void
+    {
+        $gateway = $this->createGatewayWithSettings();
+        $this->expectException(\InvalidArgumentException::class);
+        $gateway->getMeetingsForCustomer("10254' or '1'='1");
+    }
+
+    public function testGetContractLinesForCustomerRejectsODataInjection(): void
+    {
+        $gateway = $this->createGatewayWithSettings();
+        $this->expectException(\InvalidArgumentException::class);
+        $gateway->getContractLinesForCustomer("10254' or '1'='1");
+    }
+
+    public function testGetEscalationTicketsForCustomerRejectsODataInjection(): void
+    {
+        $gateway = $this->createGatewayWithSettings();
+        $this->expectException(\InvalidArgumentException::class);
+        $gateway->getEscalationTicketsForCustomer("10254' or '1'='1");
+    }
+
+    public function testGetTicketsForControllingRejectsODataInjection(): void
+    {
+        $gateway = $this->createGatewayWithSettings();
+        $this->expectException(\InvalidArgumentException::class);
+        $gateway->getTicketsForControlling("10254' or '1'='1");
+    }
+
+    public function testGetMeetingsForCustomerRejectsParenthesesInjection(): void
+    {
+        $gateway = $this->createGatewayWithSettings();
+        $this->expectException(\InvalidArgumentException::class);
+        $gateway->getMeetingsForCustomer("') or true or contains(Name,'");
+    }
+
+    public function testGetContractLinesForCustomerRejectsParenthesesInjection(): void
+    {
+        $gateway = $this->createGatewayWithSettings();
+        $this->expectException(\InvalidArgumentException::class);
+        $gateway->getContractLinesForCustomer("10254) or (1 eq 1");
+    }
+
+    // ── Valid customerNo values still pass strict validation ───────
+
+    public function testGetMeetingsForCustomerAcceptsValidCustomerNo(): void
+    {
+        $gateway = $this->createGatewayWithSettings();
+        $threw = false;
+        try {
+            $gateway->getMeetingsForCustomer('10254');
+        } catch (\InvalidArgumentException) {
+            $this->fail('Valid customer number should pass strict input validation');
+        } catch (\RuntimeException) {
+            $threw = true;
+        }
+        // Either cURL failed (expected) or returned empty — both are fine
+        $this->assertTrue(true);
+    }
+
+    public function testGetContractLinesForCustomerAcceptsCustomerNoWithDash(): void
+    {
+        $gateway = $this->createGatewayWithSettings();
+        $threw = false;
+        try {
+            $gateway->getContractLinesForCustomer('10254-A');
+        } catch (\InvalidArgumentException) {
+            $this->fail('Customer number with dash should pass strict input validation');
+        } catch (\RuntimeException) {
+            $threw = true;
+        }
+        $this->assertTrue(true);
+    }
 }
diff --git a/modules/helpdesk/tests/Module/Helpdesk/Service/DebitorCacheControlTest.php b/modules/helpdesk/tests/Module/Helpdesk/Service/DebitorCacheControlTest.php
index 617087e..3a9fde0 100644
--- a/modules/helpdesk/tests/Module/Helpdesk/Service/DebitorCacheControlTest.php
+++ b/modules/helpdesk/tests/Module/Helpdesk/Service/DebitorCacheControlTest.php
@@ -71,4 +71,16 @@ class DebitorCacheControlTest extends TestCase
         $keys = DebitorCacheControl::allDebitorCacheKeys('7', '10610');
         $this->assertContains('module.helpdesk.debitor.v2.controlling-tickets.7.10610', $keys);
     }
+
+    public function testMeetingsKeyFormat(): void
+    {
+        $key = DebitorCacheControl::meetingsKey('3', '10254');
+        $this->assertSame('module.helpdesk.debitor.v2.meetings.3.10254', $key);
+    }
+
+    public function testAllDebitorCacheKeysIncludesMeetingsKey(): void
+    {
+        $keys = DebitorCacheControl::allDebitorCacheKeys('3', '10254');
+        $this->assertContains('module.helpdesk.debitor.v2.meetings.3.10254', $keys);
+    }
 }