diff --git a/.github/copilot-instructions.md b/.github/copilot-instructions.md
index 3714c41e0..1679aae3b 100644
--- a/.github/copilot-instructions.md
+++ b/.github/copilot-instructions.md
@@ -134,6 +134,10 @@ php artisan queue:work
  - Tests have inline comment blocks above sections (/* Arrange */, /* Act */, /* Assert */).
  - Tests must be meaningful - avoid simple "ok" checks; validate actual behavior and data.
  - Use data providers for testing multiple scenarios with the same logic.
+ - **NEVER extend `Tests\TestCase`** - all tests must extend one of the abstract test cases from `Modules/Core/Tests/`:
+   - `AbstractTestCase` - Basic test case with application bootstrap
+   - `AbstractAdminPanelTestCase` - For admin panel tests with RefreshDatabase
+   - `AbstractCompanyPanelTestCase` - For company panel tests with multi-tenancy
 
 ### Export System Rules
 
diff --git a/.junie/guidelines.md b/.junie/guidelines.md
index c73466b35..7bcd817a9 100644
--- a/.junie/guidelines.md
+++ b/.junie/guidelines.md
@@ -183,6 +183,10 @@ class InvoiceServiceTest extends AbstractCompanyPanelTestCase
 4. **Happy Paths Last:** Place success scenarios at the end
 5. **Reusable Setup:** Abstract test cases for fixtures, not inline
 6. **Comment Blocks:** Use `/* Arrange */`, `/* Act */`, `/* Assert */`
+7. **NEVER extend `Tests\TestCase`:** All tests must extend one of the abstract test cases from `Modules/Core/Tests/`:
+   - `AbstractTestCase` - Basic test case with application bootstrap
+   - `AbstractAdminPanelTestCase` - For admin panel tests with RefreshDatabase
+   - `AbstractCompanyPanelTestCase` - For company panel tests with multi-tenancy
 
 ### Export Testing
 ```php
diff --git a/Modules/Core/Tests/Feature/NumberingPanelAccessTest.php b/Modules/Core/Tests/Feature/NumberingPanelAccessTest.php
index 8d8bf5322..88ffa8ad2 100644
--- a/Modules/Core/Tests/Feature/NumberingPanelAccessTest.php
+++ b/Modules/Core/Tests/Feature/NumberingPanelAccessTest.php
@@ -6,10 +6,10 @@
 use Modules\Core\Models\Numbering;
 use Modules\Core\Models\User;
 use Modules\Core\Services\NumberingService;
+use Modules\Core\Tests\AbstractTestCase;
 use PHPUnit\Framework\Attributes\Test;
-use Tests\TestCase;
 
-class NumberingPanelAccessTest extends TestCase
+class NumberingPanelAccessTest extends AbstractTestCase
 {
     private NumberingService $service;
 
diff --git a/Modules/Core/Tests/Unit/NumberGenerator/NumberGeneratorTemplateTest.php b/Modules/Core/Tests/Unit/NumberGenerator/NumberGeneratorTemplateTest.php
index 4714105c3..7abb9827b 100644
--- a/Modules/Core/Tests/Unit/NumberGenerator/NumberGeneratorTemplateTest.php
+++ b/Modules/Core/Tests/Unit/NumberGenerator/NumberGeneratorTemplateTest.php
@@ -7,12 +7,12 @@
 use Modules\Core\Enums\NumberingType;
 use Modules\Core\Models\Company;
 use Modules\Core\Models\Numbering;
+use Modules\Core\Tests\AbstractTestCase;
 use Modules\Projects\Support\ProjectNumberGenerator;
 use PHPUnit\Framework\Attributes\Group;
 use PHPUnit\Framework\Attributes\Test;
-use Tests\TestCase;
 
-class NumberGeneratorTemplateTest extends TestCase
+class NumberGeneratorTemplateTest extends AbstractTestCase
 {
     use RefreshDatabase;
 
diff --git a/Modules/Core/Tests/Unit/Services/NumberingCompanyIsolationTest.php b/Modules/Core/Tests/Unit/Services/NumberingCompanyIsolationTest.php
index 641b8091f..b80fe06ba 100644
--- a/Modules/Core/Tests/Unit/Services/NumberingCompanyIsolationTest.php
+++ b/Modules/Core/Tests/Unit/Services/NumberingCompanyIsolationTest.php
@@ -8,14 +8,14 @@
 use Modules\Core\Models\Company;
 use Modules\Core\Models\Numbering;
 use Modules\Core\Services\NumberingService;
+use Modules\Core\Tests\AbstractTestCase;
 use Modules\Expenses\Support\ExpenseNumberGenerator;
 use Modules\Projects\Models\Task;
 use Modules\Projects\Support\TaskNumberGenerator;
 use PHPUnit\Framework\Attributes\Group;
 use PHPUnit\Framework\Attributes\Test;
-use Tests\TestCase;
 
-class NumberingCompanyIsolationTest extends TestCase
+class NumberingCompanyIsolationTest extends AbstractTestCase
 {
     use RefreshDatabase;
 
diff --git a/Modules/Invoices/Tests/Feature/InvoiceDuplicateNumberPreventionTest.php b/Modules/Invoices/Tests/Feature/InvoiceDuplicateNumberPreventionTest.php
index 9461584cb..d186ab3aa 100644
--- a/Modules/Invoices/Tests/Feature/InvoiceDuplicateNumberPreventionTest.php
+++ b/Modules/Invoices/Tests/Feature/InvoiceDuplicateNumberPreventionTest.php
@@ -4,12 +4,12 @@
 
 use Modules\Core\Models\Company;
 use Modules\Core\Models\Numbering;
+use Modules\Core\Tests\AbstractTestCase;
 use Modules\Invoices\Models\Invoice;
 use PHPUnit\Framework\Attributes\Test;
 use RuntimeException;
-use Tests\TestCase;
 
-class InvoiceDuplicateNumberPreventionTest extends TestCase
+class InvoiceDuplicateNumberPreventionTest extends AbstractTestCase
 {
     #[Test]
     public function it_prevents_duplicate_invoice_numbers_within_same_company(): void
diff --git a/Modules/Invoices/Tests/Feature/InvoiceNumberingSchemeChangeTest.php b/Modules/Invoices/Tests/Feature/InvoiceNumberingSchemeChangeTest.php
index 42a9bb6a0..9fc1eea37 100644
--- a/Modules/Invoices/Tests/Feature/InvoiceNumberingSchemeChangeTest.php
+++ b/Modules/Invoices/Tests/Feature/InvoiceNumberingSchemeChangeTest.php
@@ -4,12 +4,12 @@
 
 use Illuminate\Foundation\Testing\RefreshDatabase;
 use Modules\Core\Models\Numbering;
+use Modules\Core\Tests\AbstractTestCase;
 use Modules\Invoices\Models\Invoice;
 use Modules\Invoices\Support\InvoiceNumberGenerator;
 use PHPUnit\Framework\Attributes\Test;
-use Tests\TestCase;
 
-class InvoiceNumberingSchemeChangeTest extends TestCase
+class InvoiceNumberingSchemeChangeTest extends AbstractTestCase
 {
     use RefreshDatabase;
 
diff --git a/Modules/Quotes/Tests/Feature/QuoteDuplicateNumberPreventionTest.php b/Modules/Quotes/Tests/Feature/QuoteDuplicateNumberPreventionTest.php
index b31202ff8..37f51b28f 100644
--- a/Modules/Quotes/Tests/Feature/QuoteDuplicateNumberPreventionTest.php
+++ b/Modules/Quotes/Tests/Feature/QuoteDuplicateNumberPreventionTest.php
@@ -4,12 +4,12 @@
 
 use Modules\Core\Models\Company;
 use Modules\Core\Models\Numbering;
+use Modules\Core\Tests\AbstractTestCase;
 use Modules\Quotes\Models\Quote;
 use PHPUnit\Framework\Attributes\Test;
 use RuntimeException;
-use Tests\TestCase;
 
-class QuoteDuplicateNumberPreventionTest extends TestCase
+class QuoteDuplicateNumberPreventionTest extends AbstractTestCase
 {
     #[Test]
     public function it_prevents_duplicate_quote_numbers_within_same_company(): void