question: public ProjectImporter ( final File rootFolder ) { assertNotNull ( "Root folder cannot be null." , rootFolder ) ; assertTrue ( "Root folder does not exist: " + rootFolder , rootFolder . exists ( ) ) ; assertTrue ( "Root folder must be a folder. But was a file: " + rootFolder , rootFolder . isDirectory ( ) ) ; assertTrue ( "Root folder directory content cannot be read: " + rootFolder , rootFolder . canRead ( ) ) ; assertTrue ( "No files were found in the directory: " + rootFolder , null != rootFolder . listFiles ( ) ) ; this . rootFolder = rootFolder ; }
target:  Creates a project importer with the root folder of all projects that has to be imported for the test.