diff --git a/rules-tests/CodeQuality/Rector/MethodCall/AssertEmptyNullableObjectToAssertInstanceofRector/Fixture/include_assert_not_null.php.inc b/rules-tests/CodeQuality/Rector/MethodCall/AssertEmptyNullableObjectToAssertInstanceofRector/Fixture/include_assert_not_null.php.inc
new file mode 100644
index 00000000..d54bd5f3
--- /dev/null
+++ b/rules-tests/CodeQuality/Rector/MethodCall/AssertEmptyNullableObjectToAssertInstanceofRector/Fixture/include_assert_not_null.php.inc
@@ -0,0 +1,37 @@
+<?php
+
+namespace Rector\PHPUnit\Tests\CodeQuality\Rector\MethodCall\AssertEmptyNullableObjectToAssertInstanceofRector\Fixture;
+
+use CodeQuality\Rector\MethodCall\AssertEmptyNullableObjectToAssertInstanceofRector\Source\SomeTypeObject;
+use PHPUnit\Framework\TestCase;
+
+final class IncludeAssertNotNull extends TestCase
+{
+    public function test()
+    {
+        $someObject = mt_rand(0, 1) ? new SomeTypeObject() : null;
+
+        $this->assertNotNull($someObject);
+    }
+}
+
+?>
+-----
+<?php
+
+namespace Rector\PHPUnit\Tests\CodeQuality\Rector\MethodCall\AssertEmptyNullableObjectToAssertInstanceofRector\Fixture;
+
+use CodeQuality\Rector\MethodCall\AssertEmptyNullableObjectToAssertInstanceofRector\Source\SomeTypeObject;
+use PHPUnit\Framework\TestCase;
+
+final class IncludeAssertNotNull extends TestCase
+{
+    public function test()
+    {
+        $someObject = mt_rand(0, 1) ? new SomeTypeObject() : null;
+
+        $this->assertInstanceOf(\CodeQuality\Rector\MethodCall\AssertEmptyNullableObjectToAssertInstanceofRector\Source\SomeTypeObject::class, $someObject);
+    }
+}
+
+?>
diff --git a/rules-tests/CodeQuality/Rector/MethodCall/AssertEmptyNullableObjectToAssertInstanceofRector/Fixture/include_assert_null.php.inc b/rules-tests/CodeQuality/Rector/MethodCall/AssertEmptyNullableObjectToAssertInstanceofRector/Fixture/include_assert_null.php.inc
new file mode 100644
index 00000000..cdfa8580
--- /dev/null
+++ b/rules-tests/CodeQuality/Rector/MethodCall/AssertEmptyNullableObjectToAssertInstanceofRector/Fixture/include_assert_null.php.inc
@@ -0,0 +1,37 @@
+<?php
+
+namespace Rector\PHPUnit\Tests\CodeQuality\Rector\MethodCall\AssertEmptyNullableObjectToAssertInstanceofRector\Fixture;
+
+use CodeQuality\Rector\MethodCall\AssertEmptyNullableObjectToAssertInstanceofRector\Source\SomeTypeObject;
+use PHPUnit\Framework\TestCase;
+
+final class IncludeAssertNull extends TestCase
+{
+    public function test()
+    {
+        $someObject = mt_rand(0, 1) ? new SomeTypeObject() : null;
+
+        $this->assertNull($someObject);
+    }
+}
+
+?>
+-----
+<?php
+
+namespace Rector\PHPUnit\Tests\CodeQuality\Rector\MethodCall\AssertEmptyNullableObjectToAssertInstanceofRector\Fixture;
+
+use CodeQuality\Rector\MethodCall\AssertEmptyNullableObjectToAssertInstanceofRector\Source\SomeTypeObject;
+use PHPUnit\Framework\TestCase;
+
+final class IncludeAssertNull extends TestCase
+{
+    public function test()
+    {
+        $someObject = mt_rand(0, 1) ? new SomeTypeObject() : null;
+
+        $this->assertNotInstanceOf(\CodeQuality\Rector\MethodCall\AssertEmptyNullableObjectToAssertInstanceofRector\Source\SomeTypeObject::class, $someObject);
+    }
+}
+
+?>
diff --git a/rules/CodeQuality/Rector/FuncCall/AssertFuncCallToPHPUnitAssertRector.php b/rules/CodeQuality/Rector/FuncCall/AssertFuncCallToPHPUnitAssertRector.php
index 50508fa6..3389b304 100644
--- a/rules/CodeQuality/Rector/FuncCall/AssertFuncCallToPHPUnitAssertRector.php
+++ b/rules/CodeQuality/Rector/FuncCall/AssertFuncCallToPHPUnitAssertRector.php
@@ -149,6 +149,7 @@ private function isTestFilePath(FuncCall $funcCall): bool
         if (str_ends_with($className, 'Test')) {
             return true;
         }
+
         return str_ends_with($className, 'TestCase');
     }
 
diff --git a/rules/CodeQuality/Rector/MethodCall/AssertEmptyNullableObjectToAssertInstanceofRector.php b/rules/CodeQuality/Rector/MethodCall/AssertEmptyNullableObjectToAssertInstanceofRector.php
index 294e8e6a..1edefd41 100644
--- a/rules/CodeQuality/Rector/MethodCall/AssertEmptyNullableObjectToAssertInstanceofRector.php
+++ b/rules/CodeQuality/Rector/MethodCall/AssertEmptyNullableObjectToAssertInstanceofRector.php
@@ -30,9 +30,11 @@ public function __construct(
 
     public function getRuleDefinition(): RuleDefinition
     {
-        return new RuleDefinition('Change assertNotEmpty() on an object to more clear assertInstanceof()', [
-            new CodeSample(
-                <<<'CODE_SAMPLE'
+        return new RuleDefinition(
+            'Change assertNotEmpty() and assertNotNull() on an object to more clear assertInstanceof()',
+            [
+                new CodeSample(
+                    <<<'CODE_SAMPLE'
 use PHPUnit\Framework\TestCase;
 
 class SomeClass extends TestCase
@@ -46,8 +48,8 @@ public function test()
 }
 CODE_SAMPLE
 
-                ,
-                <<<'CODE_SAMPLE'
+                    ,
+                    <<<'CODE_SAMPLE'
 use PHPUnit\Framework\TestCase;
 
 class SomeClass extends TestCase
@@ -60,8 +62,10 @@ public function test()
     }
 }
 CODE_SAMPLE
-            ),
-        ]);
+                ),
+
+            ]
+        );
     }
 
     /**
@@ -81,7 +85,7 @@ public function refactor(Node $node): ?Node
             return null;
         }
 
-        if (! $this->isNames($node->name, ['assertNotEmpty', 'assertEmpty'])) {
+        if (! $this->isNames($node->name, ['assertNotEmpty', 'assertEmpty', 'assertNull', 'assertNotNull'])) {
             return null;
         }
 
@@ -105,7 +109,10 @@ public function refactor(Node $node): ?Node
             return null;
         }
 
-        $methodName = $this->isName($node->name, 'assertEmpty') ? 'assertNotInstanceOf' : 'assertInstanceOf';
+        $methodName = $this->isNames(
+            $node->name,
+            ['assertEmpty', 'assertNull']
+        ) ? 'assertNotInstanceOf' : 'assertInstanceOf';
 
         $node->name = new Identifier($methodName);