addBook(new Book('Learning PHP Design Patterns', 'William Sanders')); $bookList->addBook(new Book('Professional Php Design Patterns', 'Aaron Saray')); $bookList->addBook(new Book('Clean Code', 'Robert C. Martin')); $books = []; foreach ($bookList as $book) { $books[] = $book->getAuthorAndTitle(); } $this->assertSame( [ 'Learning PHP Design Patterns by William Sanders', 'Professional Php Design Patterns by Aaron Saray', 'Clean Code by Robert C. Martin', ], $books ); } public function testCanIterateOverBookListAfterRemovingBook() { $book = new Book('Clean Code', 'Robert C. Martin'); $book2 = new Book('Professional Php Design Patterns', 'Aaron Saray'); $bookList = new BookList(); $bookList->addBook($book); $bookList->addBook($book2); $bookList->removeBook($book); $books = []; foreach ($bookList as $book) { $books[] = $book->getAuthorAndTitle(); } $this->assertSame( ['Professional Php Design Patterns by Aaron Saray'], $books ); } public function testCanAddBookToList() { $book = new Book('Clean Code', 'Robert C. Martin'); $bookList = new BookList(); $bookList->addBook($book); $this->assertCount(1, $bookList); } public function testCanRemoveBookFromList() { $book = new Book('Clean Code', 'Robert C. Martin'); $bookList = new BookList(); $bookList->addBook($book); $bookList->removeBook($book); $this->assertCount(0, $bookList); } }