Improve error messages and remove redundant teardown.

src/ORM/Association/BelongsToMany.php

@@ -1282,13 +1282,13 @@ class BelongsToMany extends Association
     protected function _checkPersistenceStatus($sourceEntity, array $targetEntities)
     {
         if ($sourceEntity->isNew()) {
-            $error = 'Source entity needs to be persisted before proceeding';
+            $error = 'Source entity needs to be persisted before links can be created or removed.';
             throw new InvalidArgumentException($error);
         }
 
         foreach ($targetEntities as $entity) {
             if ($entity->isNew()) {
-                $error = 'Cannot link not persisted entities';
+                $error = 'Cannot link entities that have not been persisted yet.';
                 throw new InvalidArgumentException($error);
             }
         }

tests/TestCase/ORM/Association/BelongsToManyTest.php

@@ -67,17 +67,6 @@ class BelongsToManyTest extends TestCase
     }
 
     /**
-     * Tear down
-     *
-     * @return void
-     */
-    public function tearDown()
-    {
-        parent::tearDown();
-        TableRegistry::clear();
-    }
-
-    /**
      * Tests that foreignKey() returns the correct configured value
      *
      * @return void
@@ -390,7 +379,7 @@ class BelongsToManyTest extends TestCase
      * Test linking entities having a non persisted source entity
      *
      * @expectedException \InvalidArgumentException
-     * @expectedExceptionMessage Source entity needs to be persisted before proceeding
+     * @expectedExceptionMessage Source entity needs to be persisted before links can be created or removed
      * @return void
      */
     public function testLinkWithNotPersistedSource()
@@ -410,7 +399,7 @@ class BelongsToManyTest extends TestCase
      * Test liking entities having a non persisted target entity
      *
      * @expectedException \InvalidArgumentException
-     * @expectedExceptionMessage Cannot link not persisted entities
+     * @expectedExceptionMessage Cannot link entities that have not been persisted yet
      * @return void
      */
     public function testLinkWithNotPersistedTarget()
@@ -482,7 +471,7 @@ class BelongsToManyTest extends TestCase
      * Test liking entities having a non persisted source entity
      *
      * @expectedException \InvalidArgumentException
-     * @expectedExceptionMessage Source entity needs to be persisted before proceeding
+     * @expectedExceptionMessage Source entity needs to be persisted before links can be created or removed
      * @return void
      */
     public function testUnlinkWithNotPersistedSource()
@@ -502,7 +491,7 @@ class BelongsToManyTest extends TestCase
      * Test liking entities having a non persisted target entity
      *
      * @expectedException \InvalidArgumentException
-     * @expectedExceptionMessage Cannot link not persisted entities
+     * @expectedExceptionMessage Cannot link entities that have not been persisted
      * @return void
      */
     public function testUnlinkWithNotPersistedTarget()