/** * Class to test the ConnectFour methods. * If your code does not pass these tests, it is broken. * * It is possible that your code is broken even if it passes these * tests, so make sure the game plays properly, too. */ public class ConnectFourTest { private static int correctTests = 0; private static int totalTests = 0; public static void testConstants() { // Make sure the constants in ConnectFour.java are as they // should be. // Board size should be as expected countTest(7 == ConnectFour.COLUMNS); countTest(6 == ConnectFour.ROWS); // Student could change player chars, I guess, but shouldn't // break the logic in the process. countTest(ConnectFour.COMPUTER != ConnectFour.HUMAN); countTest(ConnectFour.HUMAN != ConnectFour.NONE); countTest(ConnectFour.NONE != ConnectFour.COMPUTER); } /** Utility method to generate empty board. */ public static char[][] emptyBoard() { char[][] result = new char[ConnectFour.ROWS][ConnectFour.COLUMNS]; for (int r = 0; r < result.length; r++) { for (int c = 0; c < result[r].length; c++) { result[r][c] = ConnectFour.NONE; } } return result; } public static void testBoardToString() { char[][] board = emptyBoard(); String emptyBoardStr = "-------\n" + "-------\n" + "-------\n" + "-------\n" + "-------\n" + "-------\n"; countTest(ConnectFour.boardToString(board).equals(emptyBoardStr)); board[0][2] = ConnectFour.HUMAN; board[1][2] = ConnectFour.COMPUTER; String boardStr = "-------\n" + "-------\n" + "-------\n" + "-------\n" + "--O----\n" + "--X----\n"; countTest(ConnectFour.boardToString(board).equals(boardStr)); } public static void testGetOppositePlayer() { countTest(ConnectFour.HUMAN == ConnectFour.getOppositePlayer(ConnectFour.COMPUTER)); countTest(ConnectFour.COMPUTER == ConnectFour.getOppositePlayer(ConnectFour.HUMAN)); } public static void testDropPiece() { char[][] board = emptyBoard(); ConnectFour.dropPiece(board, 2, ConnectFour.COMPUTER); countTest(ConnectFour.COMPUTER == board[0][2]); countTest(ConnectFour.NONE == board[1][2]); countTest(ConnectFour.NONE == board[0][1]); countTest(ConnectFour.NONE == board[0][3]); ConnectFour.dropPiece(board, 2, ConnectFour.HUMAN); countTest(ConnectFour.HUMAN == board[1][2]); countTest(ConnectFour.COMPUTER == board[0][2]); countTest(ConnectFour.NONE == board[3][2]); countTest(ConnectFour.boardToString(board).equals("-------\n" + "-------\n" + "-------\n" + "-------\n" + "--X----\n" + "--O----\n")); } public static void testUndoDrop() { char[][] board = emptyBoard(); ConnectFour.dropPiece(board, 2, ConnectFour.COMPUTER); ConnectFour.dropPiece(board, 2, ConnectFour.HUMAN); ConnectFour.undoDrop(board, 2); countTest(ConnectFour.COMPUTER == board[0][2]); countTest(ConnectFour.NONE == board[1][2]); } public static void testIsLegalMove() { char[][] board = emptyBoard(); countTest(!ConnectFour.isLegalMove(board, -1)); countTest(!ConnectFour.isLegalMove(board, 7)); countTest(ConnectFour.isLegalMove(board, 6)); ConnectFour.dropPiece(board, 2, ConnectFour.COMPUTER); ConnectFour.dropPiece(board, 2, ConnectFour.HUMAN); ConnectFour.dropPiece(board, 2, ConnectFour.COMPUTER); ConnectFour.dropPiece(board, 2, ConnectFour.HUMAN); ConnectFour.dropPiece(board, 2, ConnectFour.COMPUTER); countTest(ConnectFour.isLegalMove(board, 2)); ConnectFour.dropPiece(board, 2, ConnectFour.HUMAN); countTest(!ConnectFour.isLegalMove(board, 2)); } public static void testIsBoardFull() { char[][] board = emptyBoard(); for (int r = 0; r < ConnectFour.ROWS; r++) { for (int c = 0; c < ConnectFour.COLUMNS; c++) { countTest(!ConnectFour.isBoardFull(board)); ConnectFour.dropPiece(board, c, ConnectFour.COMPUTER); } } countTest(ConnectFour.isBoardFull(board)); } public static void testHorizontalWinner() { char[][] board = emptyBoard(); for (int c = 3; c < 7; c++) { countTest(ConnectFour.NONE == ConnectFour.findWinner(board)); ConnectFour.dropPiece(board, c, ConnectFour.COMPUTER); } countTest(ConnectFour.COMPUTER == ConnectFour.findWinner(board)); countTest(ConnectFour.COMPUTER == ConnectFour.findLocalWinner(board, 0, 3, 0, 1)); countTest(ConnectFour.COMPUTER == ConnectFour.findLocalWinner(board, 0, 6, 0, -1)); countTest(ConnectFour.NONE == ConnectFour.findLocalWinner(board, 0, 2, 0, 1)); countTest(ConnectFour.NONE == ConnectFour.findLocalWinner(board, 0, 4, 0, 1)); } public static void testHorizontalWinner2() { char[][] board = emptyBoard(); countTest(ConnectFour.NONE == ConnectFour.findWinner(board)); ConnectFour.dropPiece(board, 0, ConnectFour.HUMAN); countTest(ConnectFour.NONE == ConnectFour.findWinner(board)); ConnectFour.dropPiece(board, 1, ConnectFour.HUMAN); countTest(ConnectFour.NONE == ConnectFour.findWinner(board)); ConnectFour.dropPiece(board, 3, ConnectFour.HUMAN); countTest(ConnectFour.NONE == ConnectFour.findWinner(board)); ConnectFour.dropPiece(board, 6, ConnectFour.HUMAN); countTest(ConnectFour.NONE == ConnectFour.findWinner(board)); ConnectFour.dropPiece(board, 2, ConnectFour.HUMAN); countTest(ConnectFour.HUMAN == ConnectFour.findWinner(board)); countTest(ConnectFour.HUMAN == ConnectFour.findLocalWinner(board, 0, 0, 0, 1)); countTest(ConnectFour.NONE == ConnectFour.findLocalWinner(board, 0, 1, 0, 1)); } public static void testVerticalWinner() { char[][] board = emptyBoard(); for (int i = 0; i < 4; i++) { countTest(ConnectFour.NONE == ConnectFour.findWinner(board)); ConnectFour.dropPiece(board, 6, ConnectFour.HUMAN); } countTest(ConnectFour.HUMAN == ConnectFour.findWinner(board)); countTest(ConnectFour.HUMAN == ConnectFour.findLocalWinner(board, 0, 6, 1, 0)); countTest(ConnectFour.NONE == ConnectFour.findLocalWinner(board, 1, 6, 1, 0)); countTest(ConnectFour.HUMAN == ConnectFour.findLocalWinner(board, 3, 6, -1, 0)); countTest(ConnectFour.NONE == ConnectFour.findLocalWinner(board, 4, 6, -1, 0)); } public static void testVerticalWinner2() { char[][] board = emptyBoard(); ConnectFour.dropPiece(board, 3, ConnectFour.COMPUTER); ConnectFour.dropPiece(board, 3, ConnectFour.COMPUTER); for (int i = 0; i < 4; i++) { countTest(ConnectFour.NONE == ConnectFour.findWinner(board)); ConnectFour.dropPiece(board, 3, ConnectFour.HUMAN); } countTest(ConnectFour.HUMAN == ConnectFour.findWinner(board)); countTest(ConnectFour.HUMAN == ConnectFour.findLocalWinner(board, 2, 3, 1, 0)); countTest(ConnectFour.NONE == ConnectFour.findLocalWinner(board, 1, 3, 1, 0)); countTest(ConnectFour.HUMAN == ConnectFour.findLocalWinner(board, 5, 3, -1, 0)); countTest(ConnectFour.NONE == ConnectFour.findLocalWinner(board, 4, 3, -1, 0)); } public static void testDiagonalWinner1() { char[][] board = emptyBoard(); for (int i = 0; i < 4; i++) { for (int j = 0; j < i; j++) { countTest(ConnectFour.NONE == ConnectFour.findWinner(board)); ConnectFour.dropPiece(board, i, ConnectFour.HUMAN); } countTest(ConnectFour.NONE == ConnectFour.findWinner(board)); ConnectFour.dropPiece(board, i, ConnectFour.COMPUTER); } countTest(ConnectFour.COMPUTER == ConnectFour.findWinner(board)); countTest(ConnectFour.COMPUTER == ConnectFour.findLocalWinner(board, 0, 0, 1, 1)); countTest(ConnectFour.NONE == ConnectFour.findLocalWinner(board, 1, 1, 1, 1)); countTest(ConnectFour.COMPUTER == ConnectFour.findLocalWinner(board, 3, 3, -1, -1)); countTest(ConnectFour.NONE == ConnectFour.findLocalWinner(board, 4, 4, -1, -1)); } public static void testDiagonalWinner2() { char[][] board = emptyBoard(); for (int i = 0; i < 4; i++) { for (int j = 0; j < i; j++) { countTest(ConnectFour.NONE == ConnectFour.findWinner(board)); ConnectFour.dropPiece(board, 5 - i, ConnectFour.COMPUTER); } countTest(ConnectFour.NONE == ConnectFour.findWinner(board)); ConnectFour.dropPiece(board, 5 - i, ConnectFour.HUMAN); } countTest(ConnectFour.HUMAN == ConnectFour.findWinner(board)); countTest(ConnectFour.HUMAN == ConnectFour.findLocalWinner(board, 0, 5, 1, -1)); countTest(ConnectFour.NONE == ConnectFour.findLocalWinner(board, 1, 4, 1, -1)); countTest(ConnectFour.HUMAN == ConnectFour.findLocalWinner(board, 3, 2, -1, 1)); countTest(ConnectFour.NONE == ConnectFour.findLocalWinner(board, 4, 1, -1, 1)); } public static void testMax0() { char[][] board = emptyBoard(); for (int i = 0; i < 3; i++) { ConnectFour.dropPiece(board, i, ConnectFour.COMPUTER); ConnectFour.dropPiece(board, ConnectFour.COLUMNS - 1 - i, ConnectFour.HUMAN); countTest(ConnectFour.NONE == ConnectFour.findWinner(board)); } countTest(0 == ConnectFour.maxScoreForComputer(board, 0, 0)); ConnectFour.dropPiece(board, 3, ConnectFour.COMPUTER); countTest(10 == ConnectFour.maxScoreForComputer(board, 0, 0)); ConnectFour.undoDrop(board, 3); ConnectFour.dropPiece(board, 3, ConnectFour.HUMAN); countTest(-10 == ConnectFour.maxScoreForComputer(board, 0, 0)); } public static void testMax1() { char[][] board = emptyBoard(); // Computer cannot win in one move countTest(0 == ConnectFour.maxScoreForComputer(board, 1, 0)); ConnectFour.dropPiece(board, 0, ConnectFour.COMPUTER); ConnectFour.dropPiece(board, 0, ConnectFour.COMPUTER); ConnectFour.dropPiece(board, 0, ConnectFour.COMPUTER); // Now computer can win in one move countTest(10 == ConnectFour.maxScoreForComputer(board, 1, 0)); } public static void testMax2() { char[][] board = emptyBoard(); for (int i = 0; i < 3; i++) { ConnectFour.dropPiece(board, i + 2, ConnectFour.HUMAN); } // Computer cannot prevent human from winning countTest(-10 == ConnectFour.maxScoreForComputer(board, 2, 0)); ConnectFour.dropPiece(board, 0, ConnectFour.COMPUTER); ConnectFour.dropPiece(board, 0, ConnectFour.COMPUTER); ConnectFour.dropPiece(board, 0, ConnectFour.COMPUTER); // Now computer can win in one move countTest(10 == ConnectFour.maxScoreForComputer(board, 2, 0)); } public static void testMin3() { char[][] board = emptyBoard(); for (int i = 0; i < 2; i++) { ConnectFour.dropPiece(board, i + 2, ConnectFour.HUMAN); } // Human can win in three moves countTest(-10 == ConnectFour.minScoreForHuman(board, 3, 0)); } public static void testBestMoveForComputer() { char[][] board = emptyBoard(); for (int i = 0; i < 3; i++) { ConnectFour.dropPiece(board, 5, ConnectFour.HUMAN); countTest(ConnectFour.NONE == ConnectFour.findWinner(board)); } // Computer has to block countTest(5 == ConnectFour.bestMoveForComputer(board, 3)); } public static void testBestMoveFullColumn() { char[][] board = emptyBoard(); for (int i = 0; i < 3; i++) { ConnectFour.dropPiece(board, 2, ConnectFour.COMPUTER); } for (int i = 0; i < 3; i++) { ConnectFour.dropPiece(board, 2, ConnectFour.HUMAN); } countTest(ConnectFour.NONE == ConnectFour.findWinner(board)); // Computer can't block, since column is full countTest(2 != ConnectFour.bestMoveForComputer(board, 3)); } public static void testDeepSearch() { char[][] board = emptyBoard(); ConnectFour.dropPiece(board, 0, ConnectFour.HUMAN); ConnectFour.dropPiece(board, 1, ConnectFour.COMPUTER); ConnectFour.dropPiece(board, 2, ConnectFour.HUMAN); ConnectFour.dropPiece(board, 5, ConnectFour.COMPUTER); ConnectFour.dropPiece(board, 6, ConnectFour.COMPUTER); ConnectFour.dropPiece(board, 0, ConnectFour.COMPUTER); ConnectFour.dropPiece(board, 1, ConnectFour.COMPUTER); ConnectFour.dropPiece(board, 2, ConnectFour.COMPUTER); countTest(ConnectFour.NONE == ConnectFour.findWinner(board)); countTest(ConnectFour.boardToString(board).equals("-------\n" + "-------\n" + "-------\n" + "-------\n" + "OOO----\n" + "XOX--OO\n")); // Computer 4 forces human to block at 3, but then computer wins at 3 // OR Computer 3 forces human to block at 3 or 4, computer still wins countTest(4 == ConnectFour.bestMoveForComputer(board, 2) || 3 == ConnectFour.bestMoveForComputer(board, 2)); // This sequence can't be seen in a shallow search countTest(4 != ConnectFour.bestMoveForComputer(board, 1) && 3 != ConnectFour.bestMoveForComputer(board, 1)); } private static void clearCounts() { correctTests = 0; totalTests = 0; } private static void countTest(boolean correct) { if(correct) { correctTests++; } else { // Uncomment next line for a trace of which test failed. //new Exception("Failed Test").printStackTrace(); } totalTests++; } public static void main(String[] args) { clearCounts(); testConstants(); testBoardToString(); testGetOppositePlayer(); testDropPiece(); testUndoDrop(); testIsLegalMove(); testIsBoardFull(); testHorizontalWinner(); testHorizontalWinner2(); testVerticalWinner(); testVerticalWinner2(); testDiagonalWinner1(); testDiagonalWinner2(); testMax0(); testMax1(); testMax2(); testMin3(); testBestMoveForComputer(); testBestMoveFullColumn(); testDeepSearch(); System.out.println("Passed " + correctTests + " out of " + totalTests + " tests."); } }