minor #38931 Set constant visibility in tests to private where possible (derrabus)

This PR was merged into the 4.4 branch.

Discussion
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Set constant visibility in tests to private where possible

| Q             | A
| ------------- | ---
| Branch?       | 4.4
| Bug fix?      | no
| New feature?  | no
| Deprecations? | no
| Tickets       | N/A
| License       | MIT
| Doc PR        | N/A

As discussed on Slack, this PR prepares the introduction of a CS fixer rule to enforce explicit visibility declarations for constants. I've checked class constants in test and fixture classes and if I only found usages within the same class, I've declared them `private`. This way, I also found a few constants that weren't used at all anymore, so I've removed those.

Commits
-------

43ce6dfe44 Set constant visibility in tests to private where possible.

Author: fabpot

Tests/Mapping/ClassMetadataTest.php

@@ -24,10 +24,10 @@
 
 class ClassMetadataTest extends TestCase
 {
-    const CLASSNAME = 'Symfony\Component\Validator\Tests\Fixtures\Entity';
-    const PARENTCLASS = 'Symfony\Component\Validator\Tests\Fixtures\EntityParent';
-    const PROVIDERCLASS = 'Symfony\Component\Validator\Tests\Fixtures\GroupSequenceProviderEntity';
-    const PROVIDERCHILDCLASS = 'Symfony\Component\Validator\Tests\Fixtures\GroupSequenceProviderChildEntity';
+    private const CLASSNAME = 'Symfony\Component\Validator\Tests\Fixtures\Entity';
+    private const PARENTCLASS = 'Symfony\Component\Validator\Tests\Fixtures\EntityParent';
+    private const PROVIDERCLASS = 'Symfony\Component\Validator\Tests\Fixtures\GroupSequenceProviderEntity';
+    private const PROVIDERCHILDCLASS = 'Symfony\Component\Validator\Tests\Fixtures\GroupSequenceProviderChildEntity';
 
     protected $metadata;
 

Tests/Mapping/Factory/LazyLoadingMetadataFactoryTest.php

@@ -26,11 +26,9 @@
 
 class LazyLoadingMetadataFactoryTest extends TestCase
 {
-    const CLASS_NAME = 'Symfony\Component\Validator\Tests\Fixtures\Entity';
-    const PARENT_CLASS = 'Symfony\Component\Validator\Tests\Fixtures\EntityParent';
-    const INTERFACE_A_CLASS = 'Symfony\Component\Validator\Tests\Fixtures\EntityInterfaceA';
-    const INTERFACE_B_CLASS = 'Symfony\Component\Validator\Tests\Fixtures\EntityInterfaceB';
-    const PARENT_INTERFACE_CLASS = 'Symfony\Component\Validator\Tests\Fixtures\EntityParentInterface';
+    private const CLASS_NAME = 'Symfony\Component\Validator\Tests\Fixtures\Entity';
+    private const PARENT_CLASS = 'Symfony\Component\Validator\Tests\Fixtures\EntityParent';
+    private const INTERFACE_A_CLASS = 'Symfony\Component\Validator\Tests\Fixtures\EntityInterfaceA';
 
     public function testLoadClassMetadataWithInterface()
     {

Tests/Mapping/GetterMetadataTest.php

@@ -17,7 +17,7 @@
 
 class GetterMetadataTest extends TestCase
 {
-    const CLASSNAME = 'Symfony\Component\Validator\Tests\Fixtures\Entity';
+    private const CLASSNAME = 'Symfony\Component\Validator\Tests\Fixtures\Entity';
 
     public function testInvalidPropertyName()
     {

Tests/Mapping/PropertyMetadataTest.php

@@ -19,10 +19,10 @@
 
 class PropertyMetadataTest extends TestCase
 {
-    const CLASSNAME = 'Symfony\Component\Validator\Tests\Fixtures\Entity';
-    const CLASSNAME_74 = 'Symfony\Component\Validator\Tests\Fixtures\Entity_74';
-    const CLASSNAME_74_PROXY = 'Symfony\Component\Validator\Tests\Fixtures\Entity_74_Proxy';
-    const PARENTCLASS = 'Symfony\Component\Validator\Tests\Fixtures\EntityParent';
+    private const CLASSNAME = 'Symfony\Component\Validator\Tests\Fixtures\Entity';
+    private const CLASSNAME_74 = 'Symfony\Component\Validator\Tests\Fixtures\Entity_74';
+    private const CLASSNAME_74_PROXY = 'Symfony\Component\Validator\Tests\Fixtures\Entity_74_Proxy';
+    private const PARENTCLASS = 'Symfony\Component\Validator\Tests\Fixtures\EntityParent';
 
     public function testInvalidPropertyName()
     {