diff --git a/tests/Feature/Payments/CreditPaymentTest.php b/tests/Feature/Payments/CreditPaymentTest.php
new file mode 100644
index 000000000000..a325d5618d89
--- /dev/null
+++ b/tests/Feature/Payments/CreditPaymentTest.php
@@ -0,0 +1,220 @@
+<?php
+/**
+ * Invoice Ninja (https://invoiceninja.com).
+ *
+ * @link https://github.com/invoiceninja/invoiceninja source repository
+ *
+ * @copyright Copyright (c) 2021. Invoice Ninja LLC (https://invoiceninja.com)
+ *
+ * @license https://opensource.org/licenses/AAL
+ */
+namespace Tests\Feature;
+
+use App\DataMapper\ClientSettings;
+use App\Factory\ClientFactory;
+use App\Factory\CreditFactory;
+use App\Factory\InvoiceFactory;
+use App\Factory\InvoiceItemFactory;
+use App\Factory\PaymentFactory;
+use App\Helpers\Invoice\InvoiceSum;
+use App\Models\Client;
+use App\Models\ClientContact;
+use App\Models\Credit;
+use App\Models\Invoice;
+use App\Models\Payment;
+use App\Utils\Traits\MakesHash;
+use Illuminate\Database\Eloquent\Model;
+use Illuminate\Foundation\Testing\DatabaseTransactions;
+use Illuminate\Foundation\Testing\WithoutEvents;
+use Illuminate\Routing\Middleware\ThrottleRequests;
+use Illuminate\Support\Facades\Session;
+use Illuminate\Validation\ValidationException;
+use Tests\MockAccountData;
+use Tests\MockUnitData;
+use Tests\TestCase;
+
+/**
+ * @test
+ */
+class CreditPaymentTest extends TestCase
+{
+    use MakesHash;
+    use DatabaseTransactions;
+    use MockUnitData;
+    use WithoutEvents;
+
+    public function setUp() :void
+    {
+        parent::setUp();
+
+        Session::start();
+
+        $this->faker = \Faker\Factory::create();
+
+        Model::reguard();
+
+        $this->makeTestData();
+        $this->withoutExceptionHandling();
+
+        $this->withoutMiddleware(
+            ThrottleRequests::class
+        );
+    }
+
+    public function testCreditPayments()
+    {
+
+        $invoice = Invoice::factory()->create(['user_id' => $this->user->id, 'company_id' => $this->company->id, 'client_id' => $this->client->id]);
+
+        $invoice->line_items = $this->buildLineItems();
+        $invoice->uses_inclusive_taxes = false;
+
+        // $invoice->save();
+        $invoice_calc = new InvoiceSum($invoice);
+        $invoice_calc->build();
+        $invoice = $invoice_calc->getInvoice();
+        $invoice->setRelation('client', $this->client);
+        $invoice->setRelation('company', $this->company);
+        $invoice->save();
+
+        $credit = Credit::factory()->create(['user_id' => $this->user->id, 'company_id' => $this->company->id, 'client_id' => $this->client->id]);
+
+        $credit->line_items = $this->buildLineItems();
+        $credit->uses_inclusive_taxes = false;
+
+        // $invoice->save();
+        $invoice_calc = new InvoiceSum($credit);
+        $invoice_calc->build();
+        $credit = $invoice_calc->getCredit();
+        $credit->setRelation('client', $this->client);
+        $credit->setRelation('company', $this->company);
+        $credit->save();
+
+
+       $data = [
+            'amount' => 0,
+            'client_id' => $this->client->hashed_id,
+            'invoices' => [
+                [
+                    'invoice_id' => $invoice->hashed_id,
+                    'amount' => 10,
+                ],
+            ],
+            'credits' => [
+            ],
+            'date' => '2019/12/12',
+        ];
+
+        $response = false;
+
+        try {
+            $response = $this->withHeaders([
+            'X-API-SECRET' => config('ninja.api_secret'),
+            'X-API-TOKEN' => $this->token,
+        ])->post('/api/v1/payments/', $data);
+        } catch (ValidationException $e) {
+            $message = json_decode($e->validator->getMessageBag(), 1);
+            \Log::error(print_r($e->validator->getMessageBag(), 1));
+        }
+
+        // $response->assertStatus(200);
+
+        // $arr = $response->json();
+
+        // $payment_id = $arr['data']['id'];
+
+        // $payment = Payment::whereId($this->decodePrimaryKey($payment_id))->first();
+
+        // $this->assertEquals($payment->amount, 15);
+        // $this->assertEquals($payment->applied, 10);
+
+
+
+
+    }
+
+    /*
+
+    public function testDoublePaymentTestWithInvalidAmounts()
+    {
+ 
+        $data = [
+            'amount' => 15.0,
+            'client_id' => $this->encodePrimaryKey($client->id),
+            'invoices' => [
+                    [
+                        'invoice_id' => $this->encodePrimaryKey($this->invoice->id),
+                        'amount' => 10,
+                    ],
+                ],
+            'date' => '2019/12/12',
+        ];
+
+        $response = false;
+
+        try {
+            $response = $this->withHeaders([
+            'X-API-SECRET' => config('ninja.api_secret'),
+            'X-API-TOKEN' => $this->token,
+        ])->post('/api/v1/payments/', $data);
+        } catch (ValidationException $e) {
+            $message = json_decode($e->validator->getMessageBag(), 1);
+            \Log::error(print_r($e->validator->getMessageBag(), 1));
+        }
+
+        $response->assertStatus(200);
+
+        $arr = $response->json();
+
+        $payment_id = $arr['data']['id'];
+
+        $payment = Payment::whereId($this->decodePrimaryKey($payment_id))->first();
+
+        $this->assertEquals($payment->amount, 15);
+        $this->assertEquals($payment->applied, 10);
+
+        $this->invoice = null;
+        $this->invoice = InvoiceFactory::create($this->company->id, $this->user->id); //stub the company and user_id
+        $this->invoice->client_id = $client->id;
+
+        $this->invoice->line_items = $this->buildLineItems();
+        $this->invoice->uses_inclusive_taxes = false;
+
+        $this->invoice->save();
+
+        $this->invoice_calc = new InvoiceSum($this->invoice);
+        $this->invoice_calc->build();
+
+        $this->invoice = $this->invoice_calc->getInvoice();
+        $this->invoice->save();
+        $this->invoice->service()->markSent()->save();
+
+        $data = [
+            'amount' => 15.0,
+            'client_id' => $this->encodePrimaryKey($client->id),
+            'invoices' => [
+                    [
+                        'invoice_id' => $this->encodePrimaryKey($this->invoice->id),
+                        'amount' => 10,
+                    ],
+                ],
+            'date' => '2019/12/12',
+        ];
+
+        $response = false;
+
+        try {
+            $response = $this->withHeaders([
+                'X-API-SECRET' => config('ninja.api_secret'),
+                'X-API-TOKEN' => $this->token,
+            ])->put('/api/v1/payments/'.$this->encodePrimaryKey($payment->id), $data);
+        } catch (ValidationException $e) {
+            $message = json_decode($e->validator->getMessageBag(), 1);
+
+            $this->assertTrue(array_key_exists('invoices', $message));
+        }
+    }
+    */
+
+}
+
diff --git a/tests/MockUnitData.php b/tests/MockUnitData.php
index c0baea083e25..cb00239f3c78 100644
--- a/tests/MockUnitData.php
+++ b/tests/MockUnitData.php
@@ -11,10 +11,14 @@
 
 namespace Tests;
 
+use App\DataMapper\CompanySettings;
+use App\DataMapper\DefaultSettings;
+use App\Factory\InvoiceItemFactory;
 use App\Models\Account;
 use App\Models\Client;
 use App\Models\ClientContact;
 use App\Models\Company;
+use App\Models\CompanyToken;
 use App\Models\User;
 /**
  * Class MockUnitData.
@@ -33,6 +37,8 @@ trait MockUnitData
 
     public $primary_contact;
 
+    public $token;
+
     public function makeTestData()
     {
 
@@ -49,6 +55,39 @@ trait MockUnitData
             'account_id' => $this->account->id
         ]);
 
+        $userPermissions = collect([
+            'view_invoice',
+            'view_client',
+            'edit_client',
+            'edit_invoice',
+            'create_invoice',
+            'create_client',
+        ]);
+
+        $userSettings = DefaultSettings::userSettings();
+
+        $this->user->companies()->attach($this->company->id, [
+            'account_id' => $this->account->id,
+            'is_owner' => 1,
+            'is_admin' => 1,
+            'notifications' => CompanySettings::notificationDefaults(),
+            'permissions' => $userPermissions->toJson(),
+            'settings' => json_encode($userSettings),
+            'is_locked' => 0,
+        ]);
+
+
+        $this->token = \Illuminate\Support\Str::random(64);
+
+        $company_token = new CompanyToken;
+        $company_token->user_id = $this->user->id;
+        $company_token->company_id = $this->company->id;
+        $company_token->account_id = $this->account->id;
+        $company_token->name = 'test token';
+        $company_token->token = $this->token;
+        $company_token->is_system = true;
+        $company_token->save();
+
         $this->client = Client::factory()->create([
             'user_id' => $this->user->id, 
             'company_id' => $this->company->id
@@ -68,4 +107,17 @@ trait MockUnitData
         ]);
 
     }
+
+
+    public function buildLineItems()
+    {
+        $line_items = [];
+
+        $item = InvoiceItemFactory::create();
+        $item->quantity = 1;
+        $item->cost = 10;
+        $line_items[] = $item;
+
+        return $line_items;
+    }
 }
\ No newline at end of file