Fix InvoiceTest and add placeholder file for Feature folder

database/migrations/011_create_order_products_table.php

@@ -12,7 +12,7 @@ public function up(): void
             $table->id();
             $table->foreignId('order_id')->constrained();
             $table->string('sku')->nullable();
-            $table->string('product_name');
+            $table->string('product_name')->nullable();
             $table->string('color')->nullable();
 
             $table->softDeletes();

tests/Unit/InvoiceTest.php

@@ -54,7 +54,7 @@
         ->assertHasNoErrors();
 
     $this->assertDatabaseHas('invoices', [
-        'internal_id' => 'TN40001',
+        'internal_id' => 'TN4001',
         'customer_id' => $formData['customer_id'],
         'status'      => $formData['status'],
         'has_gst'     => $formData['has_gst'],
@@ -65,7 +65,7 @@
         'hst_rate'    => $hst_rate,
     ]);
 
-    $invoice = Invoice::where('internal_id', 'TN40001')->firstOrFail();
+    $invoice = Invoice::where('internal_id', 'TN4001')->firstOrFail();
 
     $this->assertEquals($invoice->orders->isEmpty(), true);
 });