Define simpletest DB for PHPUnit

templates/tests/phpunit.xml.dist

@@ -25,7 +25,7 @@
     <!-- Example SIMPLETEST_BASE_URL value: http://localhost -->
     <env name="SIMPLETEST_BASE_URL" value=""/>
     <!-- Example SIMPLETEST_DB value: mysql://username:password@localhost/databasename#table_prefix -->
-    <env name="SIMPLETEST_DB" value=""/>
+    <env name="SIMPLETEST_DB" value="sqlite://localhost//tmp/test.sqlite"/>
     <!-- Example BROWSERTEST_OUTPUT_DIRECTORY value: /path/to/webroot/sites/simpletest/browser_output -->
     <env name="BROWSERTEST_OUTPUT_DIRECTORY" value=""/>
     <!-- To disable deprecation testing completely uncomment the next line. -->