Created an class to gather information about a database and it dependencies

app/code/community/EcomDev/PHPUnit/Model/Mysql4/Db/Info.php

+<?php
+
+class EcomDev_PHPUnit_Model_Mysql4_Db_Info implements EcomDev_PHPUnit_Model_Mysql4_Db_InfoInterface
+{
+    /** @var Varien_Db_Adapter_Interface|null Current used adapter. */
+    protected $_adapter = null;
+
+    /** @var  array Information about the magento database [table => [...]]. */
+    protected $_information;
+
+
+    /**
+     * Before fetching information about a table.
+     *
+     * @return $this
+     */
+    public function fetch()
+    {
+        // reset information
+        $this->reset();
+
+        // iterate over each available table
+        $listTables = $this->getAdapter()->listTables();
+        foreach ($listTables as $tableName)
+        {
+            // describe the table
+            $data = new Varien_Object();
+            $data->setData($this->getAdapter()->describeTable($tableName));
+
+            $foreignKeys = $this->getAdapter()->getForeignKeys($tableName);
+
+            $dependency = array();
+            if (is_array($foreignKeys))
+            {
+                // add each depending table
+                foreach ($foreignKeys as $keyData)
+                {
+                    $dependency[] = $keyData['REF_TABLE_NAME'];
+                }
+            }
+            $data->setDependencies($dependency);
+
+            $this->_information[$tableName] = $data;
+        }
+    }
+
+
+    /**
+     * Get the current used adapter.
+     *
+     * @return Varien_Db_Adapter_Interface|Zend_Db_Adapter_Abstract|null
+     */
+    public function getAdapter()
+    {
+        return $this->_adapter;
+    }
+
+
+    /**
+     * Get dependencies for a single table.
+     *
+     * @param $tableName
+     *
+     * @return array|null Will return the tables that depend on the given one.
+     */
+    public function getTableDependencies($tableName)
+    {
+        if (isset($this->_information[$tableName])
+            && $this->_information[$tableName] instanceof Varien_Object
+        )
+        {
+            return $this->_information[$tableName]->getDependencies();
+        }
+
+        return null;
+    }
+
+
+    /**
+     * Reset dependencies information.
+     *
+     * @return $this
+     */
+    public function reset()
+    {
+        $this->_information = array();
+    }
+
+
+    /**
+     * Provide an adapter.
+     *
+     * @param Varien_Db_Adapter_Interface $adapter
+     *
+     * @throws InvalidArgumentException
+     * @return mixed
+     */
+    public function setAdapter($adapter)
+    {
+        if (!($adapter instanceof Varien_Db_Adapter_Interface))
+        {
+            throw new InvalidArgumentException('Unsupported adapter ' . get_class($adapter));
+        }
+
+        $this->_adapter = $adapter;
+    }
+}

app/code/community/EcomDev/PHPUnit/Model/Mysql4/Db/InfoInterface.php

+<?php
+
+interface EcomDev_PHPUnit_Model_Mysql4_Db_InfoInterface
+{
+    /**
+     * Provide an adapter.
+     *
+     * @param Varien_Db_Adapter_Interface $adapter
+     *
+     * @return mixed
+     */
+    public function setAdapter($adapter);
+
+
+    /**
+     * Get the current used adapter.
+     *
+     * @return Varien_Db_Adapter_Interface|Zend_Db_Adapter_Abstract|null
+     */
+    public function getAdapter();
+
+
+    /**
+     * Get dependencies for a single table.
+     *
+     * @param $tableName
+     *
+     * @return array Will return the tables that depend on the given one.
+     */
+    public function getTableDependencies($tableName);
+
+
+    /**
+     * Before fetching information about a table.
+     *
+     * @return $this
+     */
+    public function fetch();
+
+
+    /**
+     * Reset dependencies information.
+     *
+     * @return $this
+     */
+    public function reset();
+}

app/code/community/EcomDev/PHPUnitTest/Test/Model/Mysql4/Db/InfoTest.php

+<?php
+
+class EcomDev_PHPUnitTest_Test_Model_Mysql4_Db_InfoTest extends EcomDev_PHPUnit_Test_Case
+{
+    /** @var EcomDev_PHPUnit_Model_Mysql4_Db_InfoInterface */
+    protected $_factory;
+
+
+    /**
+     * Set up unit testing.
+     *
+     * @return void
+     */
+    public function setUp()
+    {
+        $this->_factory = new EcomDev_PHPUnit_Model_Mysql4_Db_Info();
+
+        parent::setUp();
+    }
+
+
+    /**
+     * Tear down unit testing.
+     *
+     * @return void
+     */
+    public function tearDown()
+    {
+        $this->_factory = null;
+
+        parent::tearDown();
+    }
+
+
+    /**
+     * Check if the model return the correct dependencies.
+     *
+     * @return void
+     */
+    public function testGetTheDependenciesForASpecificTable()
+    {
+        $this->_factory->setAdapter($this->_getMockedAdapter());
+        $this->_factory->fetch();
+
+        $this->assertEquals(array('mother'), $this->_factory->getTableDependencies('child'));
+        $this->assertEquals(null, $this->_factory->getTableDependencies('some_unknown'));
+    }
+
+
+    /**
+     * check if the model resets the information correct.
+     *
+     * @return void
+     */
+    public function testItCanResetTheFetchedInformation()
+    {
+        // write something to the field via reflection
+        $reflect  = $this->_getReflection();
+        $property = $reflect->getProperty('_information');
+        $property->setAccessible(true);
+        $property->setValue($this->_factory, array(uniqid()));
+
+        $this->_factory->reset();
+
+        $this->assertEmpty($property->getValue($this->_factory));
+    }
+
+
+    /**
+     * Check if the fetched information about a table is correct.
+     *
+     * @return void
+     */
+    public function testItFetchesInformationAboutATable()
+    {
+        $adapterMock = $this->_getMockedAdapter();
+
+        // check the fetched data
+        $this->_factory->setAdapter($adapterMock);
+        $this->_factory->fetch();
+
+        $reflectObject = $this->_getReflection();
+        $property      = $reflectObject->getProperty('_information');
+        $property->setAccessible(true);
+        $information = $property->getValue($this->_factory);
+
+        $this->assertEquals(array_keys($information), $adapterMock->listTables());
+
+        /** @var Varien_Object $child */
+        $child = $information['child'];
+        $this->assertNotNull($child->getDependencies());
+        $this->assertEquals(array('mother'), $child->getDependencies());
+    }
+
+
+    /**
+     * Check whether an adapter can be set and get.
+     *
+     * @return null
+     */
+    public function testYouNeedToProvideAnAdapter()
+    {
+        /** @var Varien_Db_Adapter_Interface $adapterMock */
+        $adapterMock = $this->getMock('Varien_Db_Adapter_Interface');
+        $this->assertTrue($adapterMock instanceof Varien_Db_Adapter_Interface);
+
+        $this->_factory->setAdapter($adapterMock);
+
+        $this->assertSame($adapterMock, $this->_factory->getAdapter());
+
+        return null;
+    }
+
+
+    /**
+     * Mock the adapter without any configuration.
+     *
+     * @return Varien_Db_Adapter_Pdo_Mysql|PHPUnit_Framework_MockObject_MockObject
+     */
+    protected function _getMockedAdapter()
+    {
+        /** @var Varien_Db_Adapter_Pdo_Mysql $adapterMock Mock without connecting to a server. */
+        $adapterMock = $this->getMock(
+                            'Varien_Db_Adapter_Pdo_Mysql',
+                            array(
+                                 'listTables',
+                                 'describeTable',
+                                 'getForeignKeys',
+                            ),
+                            array(),
+                            '',
+                            false // ignore original constructor
+        );
+
+        $this->assertTrue($adapterMock instanceof Varien_Db_Adapter_Pdo_Mysql);
+
+        // mock listTables: with two tables that depend on each other
+        $listTablesReturn = array('child', 'mother');
+        $adapterMock->expects($this->any())
+                    ->method('listTables')
+                    ->will(
+                    $this->returnValue($listTablesReturn)
+            );
+
+        $this->assertEquals($adapterMock->listTables(), $listTablesReturn);
+
+        // mock describeTable
+        $describeTableReturn = array(
+            array(
+                'SCHEMA_NAME'      => 'test',
+                'TABLE_NAME'       => 'foo',
+                'COLUMN_NAME'      => 'bar',
+                'COLUMN_POSITION'  => '0',
+                'DATA_TYPE'        => 'int',
+                'DEFAULT'          => '',
+                'NULLABLE'         => '',
+                'LENGTH'           => '',
+                'SCALE'            => '',
+                'UNSIGNED'         => true,
+                'PRIMARY'          => false,
+                'PRIMARY_POSITION' => null,
+                'IDENTITY'         => false,
+            ),
+        );
+
+        $adapterMock->expects($this->any())
+                    ->method('describeTable')
+                    ->will(
+                    $this->returnValue($describeTableReturn)
+            );
+
+        $this->assertEquals($adapterMock->describeTable('child'), $describeTableReturn);
+
+        // mock adapter::getForeignKeys
+        $getForeignKeysReturn = array(
+            'child'  => array(
+                'fk_mother' => array(
+                    'FK_NAME'         => 'idMother',
+                    'SCHEMA_NAME'     => 'test',
+                    'TABLE_NAME'      => 'child',
+                    'COLUMN_NAME'     => 'kf_mother',
+                    'REF_SHEMA_NAME'  => 'test',
+                    'REF_TABLE_NAME'  => 'mother',
+                    'REF_COLUMN_NAME' => 'idMother',
+                    'ON_DELETE'       => '',
+                    'ON_UPDATE'       => ''
+                ),
+            ),
+            'mother' => array(),
+        );
+
+        $adapterMock->expects($this->any())
+                    ->method('getForeignKeys')
+                    ->will(
+                    $this->returnCallback(
+                         function ($tableName) use ($getForeignKeysReturn)
+                         {
+                             return $getForeignKeysReturn[$tableName];
+                         }
+                    )
+            );
+
+        $this->assertEquals($adapterMock->getForeignKeys('child'), $getForeignKeysReturn['child']);
+        $this->assertEquals(
+             $adapterMock->getForeignKeys('mother'),
+             $getForeignKeysReturn['mother']
+        );
+
+        return $adapterMock;
+    }
+
+
+    /**
+     * Reflect the object.
+     *
+     * @return ReflectionObject
+     */
+    protected function _getReflection()
+    {
+        $reflect = new ReflectionObject($this->_factory);
+
+        return $reflect;
+    }
+}