diff --git a/core/modules/system/system.info b/core/modules/system/system.info
index 41495f3..29a9c00 100644
--- a/core/modules/system/system.info
+++ b/core/modules/system/system.info
@@ -42,4 +42,6 @@ files[] = tests/xmlrpc.test
 files[] = tests/upgrade/upgrade.test
 files[] = tests/upgrade/upgrade_bare.test
 files[] = tests/upgrade/upgrade_filled.test
+files[] = tests/upgrade/upgrade.image.test
 files[] = tests/upgrade/upgrade.language.test
+files[] = tests/upgrade/upgrade.system.test
diff --git a/core/modules/system/tests/upgrade/drupal-7.image.database.php b/core/modules/system/tests/upgrade/drupal-7.image.database.php
new file mode 100644
index 0000000..9a5dc7f
--- /dev/null
+++ b/core/modules/system/tests/upgrade/drupal-7.image.database.php
@@ -0,0 +1,66 @@
+<?php
+
+/**
+ * @file
+ * Database additions for image tests. Used in upgrade.image.test.
+ *
+ * This dump only contains data and schema components relevant for image
+ * functionality. The drupal-7.bare.database.php file is imported before
+ * this dump, so the two form the database structure expected in tests
+ * altogether.
+ */
+
+// Add image effects.
+db_insert('image_effects')->fields(array(
+  'ieid',
+  'isid',
+  'weight',
+  'name',
+  'data',
+))
+->values(array(
+  'ieid' => '1',
+  'isid' => '1',
+  'weight' => '0',
+  'name' => 'image_scale',
+  'data' => 'a:3:{s:5:"width";s:3:"177";s:6:"height";s:3:"177";s:7:"upscale";i:0;}',
+))
+->values(array(
+  'ieid' => '2',
+  'isid' => '1',
+  'weight' => '2',
+  'name' => 'image_desaturate',
+  'data' => 'a:0:{}',
+))
+->values(array(
+  'ieid' => '3',
+  'isid' => '2',
+  'weight' => '1',
+  'name' => 'image_rotate',
+  'data' => 'a:3:{s:7:"degrees";s:2:"90";s:7:"bgcolor";s:7:"#FFFFFF";s:6:"random";i:1;}',
+))
+->values(array(
+  'ieid' => '4',
+  'isid' => '2',
+  'weight' => '2',
+  'name' => 'image_desaturate',
+  'data' => 'a:0:{}',
+))
+->execute();
+
+// Add image styles.
+db_insert('image_styles')->fields(array(
+  'isid',
+  'name',
+))
+// Custom style.
+->values(array(
+  'isid' => '2',
+  'name' => 'test-custom',
+))
+// Override thumbnail style.
+->values(array(
+  'isid' => '1',
+  'name' => 'thumbnail',
+))
+->execute();
diff --git a/core/modules/system/tests/upgrade/drupal-7.system.database.php b/core/modules/system/tests/upgrade/drupal-7.system.database.php
new file mode 100644
index 0000000..e3d0fb4
--- /dev/null
+++ b/core/modules/system/tests/upgrade/drupal-7.system.database.php
@@ -0,0 +1,42 @@
+<?php
+
+/**
+ * @file
+ * Database additions for system tests. Used in upgrade.system.test.
+ *
+ * This dump only contains data and schema components relevant for system
+ * functionality. The drupal-7.filled.bare.php file is imported before
+ * this dump, so the two form the database structure expected in tests
+ * altogether.
+ */
+
+// Add non-default system settings.
+db_insert('variable')->fields(array(
+  'name',
+  'value',
+))
+->values(array(
+  'name' => 'cache',
+  'value'=> 'i:1;',
+))
+->values(array(
+    'name' => 'cache_lifetime',
+    'value' => 's:5:"10800";',
+  ))
+->values(array(
+    'name' => 'page_cache_maximum_age',
+    'value' => 's:4:"1800";',
+  ))
+->values(array(
+    'name' => 'page_compression',
+    'value' => 'i:1;',
+  ))
+->values(array(
+    'name' => 'preprocess_css',
+    'value' => 'i:1;',
+  ))
+->values(array(
+    'name' => 'preprocess_js',
+    'value' => 'i:1;',
+  ))
+->execute();
\ No newline at end of file
diff --git a/core/modules/system/tests/upgrade/upgrade.image.test b/core/modules/system/tests/upgrade/upgrade.image.test
new file mode 100644
index 0000000..2a784fe
--- /dev/null
+++ b/core/modules/system/tests/upgrade/upgrade.image.test
@@ -0,0 +1,35 @@
+<?php
+/**
+ * @file
+ * Upgrade tests for Image module.
+ */
+
+/**
+ * Test upgrade of overridden and custom image styles.
+ */
+class ImageUpgradePathTestCase extends UpgradePathTestCase {
+  public static function getInfo() {
+    return array(
+      'name' => 'Image upgrade test',
+      'description' => 'Upgrade tests for overridden and custom image styles.',
+      'group' => 'Upgrade path',
+    );
+  }
+
+  public function setUp() {
+    // Path to the database dump files.
+    $path = drupal_get_path('module', 'system') . '/tests/upgrade';
+    $this->databaseDumpFiles = array(
+      $path . '/drupal-7.bare.database.php.gz',
+      $path . '/drupal-7.image.database.php',
+    );
+    parent::setUp();
+  }
+
+  /**
+   * Tests that custom and overridden image styles have been upgraded.
+   */
+  public function testImageStyleUpgrade() {
+    $this->assertTrue($this->performUpgrade(), 'The upgrade was completed successfully.');
+  }
+}
\ No newline at end of file
diff --git a/core/modules/system/tests/upgrade/upgrade.system.test b/core/modules/system/tests/upgrade/upgrade.system.test
new file mode 100644
index 0000000..d621067
--- /dev/null
+++ b/core/modules/system/tests/upgrade/upgrade.system.test
@@ -0,0 +1,54 @@
+<?php
+/**
+ * @file
+ * Upgrade tests for the System module.
+ */
+
+/**
+ * Test upgrade of non-default values for system variables.
+ */
+class SystemUpgradePathTestCase extends UpgradePathTestCase {
+  public static function getInfo() {
+    return array(
+      'name' => 'System upgrade test',
+      'description' => 'Upgrade tests for non-default values of system variables.',
+      'group' => 'Upgrade path',
+    );
+  }
+
+  public function setUp() {
+    // Path to the database dump files.
+    $path = drupal_get_path('module', 'system') . '/tests/upgrade';
+    $this->databaseDumpFiles = array(
+      $path . '/drupal-7.bare.database.php.gz',
+      $path . '/drupal-7.system.database.php',
+    );
+    parent::setUp();
+  }
+
+  /**
+   * Tests that custom and overridden image styles have been upgraded.
+   */
+  public function testSystemVariableUpgrade() {
+    $this->assertTrue($this->performUpgrade(), 'The upgrade was completed successfully.');
+
+    // Test that the overridden values were properly converted.
+    $overrides = array(
+      'system.performance' => array(
+        'cache' => 1,
+        'cache_lifetime' => '10800',
+        'page_cache_maximum_age' => '1800',
+        'page_compression' => 1,
+        'preprocess_css' => 1,
+        'preprocess_js' => 1,
+      ),
+    );
+    foreach ($overrides as $file => $values) {
+      $config = config($file);
+      foreach ($values as $name => $value) {
+        $stored = $config->get($name);
+        $this->assertEqual($value, $stored, t('Stored value %stored for %name matches old value %value.', array('%stored' => $stored, '%name' => $name, '%value' => $value)));
+      }
+    }
+  }
+}
\ No newline at end of file