--- /dev/null
+<?php
+
+namespace Drupal\Tests\drupalmoduleupgrader\Unit\Plugin\DMU\Converter\Functions;
+
+use Pharborist\Parser;
+
+/**
+ * @group DMU.Converter.Functions
+ * @covers \Drupal\drupalmoduleupgrader\Plugin\DMU\Converter\Functions\DB
+ *
+ * Currently, the DB plugin behaves identically for every function it handles,
+ * so I'm only bothering to test db_select().
+ */
+class DBTest extends FunctionCallModifierTestBase {
+
+ public function setUp() {
+ parent::setUp();
+ $this->plugin = $this->getPlugin([], [ 'function' => 'db_select' ]);
+ }
+
+ public function testRewriteDBSelectAllowedTable() {
+ $function_call = Parser::parseExpression('db_select("session")');
+ $this->assertSame($function_call, $this->plugin->rewrite($function_call, $this->target));
+ }
+
+ public function testRewriteDBSelectForbiddenTable() {
+ $function_call = Parser::parseExpression('db_select("variable")');
+ $this->assertNull($this->plugin->rewrite($function_call, $this->target));
+ }
+
+}