Validate Database $databaseName and test getters

src/Database.php

@@ -34,9 +34,14 @@ class Database
      * @param string         $databaseName   Database name
      * @param WriteConcern   $writeConcern   Default write concern to apply
      * @param ReadPreference $readPreference Default read preference to apply
+     * @throws InvalidArgumentException if $databaseName is invalid
      */
     public function __construct(Manager $manager, $databaseName, WriteConcern $writeConcern = null, ReadPreference $readPreference = null)
     {
+        if (strlen($databaseName) < 1) {
+            throw new InvalidArgumentException('$databaseName is invalid: ' . $databaseName);
+        }
+
         $this->manager = $manager;
         $this->databaseName = (string) $databaseName;
         $this->writeConcern = $writeConcern;

tests/Database/DatabaseFunctionalTest.php

@@ -2,11 +2,41 @@
 
 namespace MongoDB\Tests\Database;
 
+use MongoDB\Database;
+
 /**
  * Functional tests for the Database class.
  */
 class DatabaseFunctionalTest extends FunctionalTestCase
 {
+    /**
+     * @expectedException MongoDB\Exception\InvalidArgumentException
+     * @dataProvider provideInvalidDatabaseValues
+     */
+    public function testConstructorDatabaseNameArgument($databaseName)
+    {
+        // TODO: Move to unit test once ManagerInterface can be mocked (PHPC-378)
+        new Database($this->manager, $databaseName);
+    }
+
+    public function provideInvalidDatabaseValues()
+    {
+        return array(
+            array(null),
+            array(''),
+        );
+    }
+
+    public function testToString()
+    {
+        $this->assertEquals($this->getDatabaseName(), (string) $this->database);
+    }
+
+    public function getGetDatabaseName()
+    {
+        $this->assertEquals($this->getDatabaseName(), $this->database->getDatabaseName());
+    }
+
     public function testDrop()
     {
         $writeResult = $this->manager->executeInsert($this->getNamespace(), array('x' => 1));