IDE One Streaming Test

import junit.framework.TestCase;

import java.io.ByteArrayOutputStream;
import java.io.PrintStream;

public class CrossingStarsTest extends TestCase {

    public void test0() {
        assertOutputEquals(new String[] {
                }, 0);
    }

    public void test1() {
        assertOutputEquals(new String[] {
                        " *",
                        "**",
                        " *",
                }, 1);
    }

    public void test2() {
        assertOutputEquals(new String[] {
                        "    *",
                        " *  *",
                        "*****",
                        " *  *",
                        "    *",
                }, 2);
    }

    public void test3() {
        assertOutputEquals(new String[] {
                        "        *",
                        "    *   *",
                        " *  *   *",
                        "*********",
                        " *  *   *",
                        "    *   *",
                        "        *",
                }, 3);
    }

    public void test4() {
        assertOutputEquals(new String[] {
                        "             *",
                        "        *    *",
                        "    *   *    *",
                        " *  *   *    *",
                        "**************",
                        " *  *   *    *",
                        "    *   *    *",
                        "        *    *",
                        "             *",
                }, 4);
    }

    public void test5() {
        assertOutputEquals(new String[] {
                        "                   *",
                        "             *     *",
                        "        *    *     *",
                        "    *   *    *     *",
                        " *  *   *    *     *",
                        "********************",
                        " *  *   *    *     *",
                        "    *   *    *     *",
                        "        *    *     *",
                        "             *     *",
                        "                   *",
                }, 5);
    }

    public void test6() {
        assertOutputEquals(new String[] {
                        "                          *",
                        "                   *      *",
                        "             *     *      *",
                        "        *    *     *      *",
                        "    *   *    *     *      *",
                        " *  *   *    *     *      *",
                        "***************************",
                        " *  *   *    *     *      *",
                        "    *   *    *     *      *",
                        "        *    *     *      *",
                        "             *     *      *",
                        "                   *      *",
                        "                          *",
                }, 6);
    }

    public void test7() {
        assertOutputEquals(new String[] {
                        "                                  *",
                        "                          *       *",
                        "                   *      *       *",
                        "             *     *      *       *",
                        "        *    *     *      *       *",
                        "    *   *    *     *      *       *",
                        " *  *   *    *     *      *       *",
                        "***********************************",
                        " *  *   *    *     *      *       *",
                        "    *   *    *     *      *       *",
                        "        *    *     *      *       *",
                        "             *     *      *       *",
                        "                   *      *       *",
                        "                          *       *",
                        "                                  *",
                }, 7);
    }

    public void test8() {
        assertOutputEquals(new String[] {
                        "                                           *",
                        "                                  *        *",
                        "                          *       *        *",
                        "                   *      *       *        *",
                        "             *     *      *       *        *",
                        "        *    *     *      *       *        *",
                        "    *   *    *     *      *       *        *",
                        " *  *   *    *     *      *       *        *",
                        "********************************************",
                        " *  *   *    *     *      *       *        *",
                        "    *   *    *     *      *       *        *",
                        "        *    *     *      *       *        *",
                        "             *     *      *       *        *",
                        "                   *      *       *        *",
                        "                          *       *        *",
                        "                                  *        *",
                        "                                           *",
                }, 8);
    }

    public void test9() {
        assertOutputEquals(new String[] {
                        "                                                     *",
                        "                                           *         *",
                        "                                  *        *         *",
                        "                          *       *        *         *",
                        "                   *      *       *        *         *",
                        "             *     *      *       *        *         *",
                        "        *    *     *      *       *        *         *",
                        "    *   *    *     *      *       *        *         *",
                        " *  *   *    *     *      *       *        *         *",
                        "******************************************************",
                        " *  *   *    *     *      *       *        *         *",
                        "    *   *    *     *      *       *        *         *",
                        "        *    *     *      *       *        *         *",
                        "             *     *      *       *        *         *",
                        "                   *      *       *        *         *",
                        "                          *       *        *         *",
                        "                                  *        *         *",
                        "                                           *         *",
                        "                                                     *",
                }, 9);
    }

    public void test10() {
        assertOutputEquals(new String[] {
                        "                                                                *",
                        "                                                     *          *",
                        "                                           *         *          *",
                        "                                  *        *         *          *",
                        "                          *       *        *         *          *",
                        "                   *      *       *        *         *          *",
                        "             *     *      *       *        *         *          *",
                        "        *    *     *      *       *        *         *          *",
                        "    *   *    *     *      *       *        *         *          *",
                        " *  *   *    *     *      *       *        *         *          *",
                        "*****************************************************************",
                        " *  *   *    *     *      *       *        *         *          *",
                        "    *   *    *     *      *       *        *         *          *",
                        "        *    *     *      *       *        *         *          *",
                        "             *     *      *       *        *         *          *",
                        "                   *      *       *        *         *          *",
                        "                          *       *        *         *          *",
                        "                                  *        *         *          *",
                        "                                           *         *          *",
                        "                                                     *          *",
                        "                                                                *",
                }, 10);
    }

    private static void assertOutputEquals(final String[] expectedOutputLines, final int n) {
        final PrintStream oldSystemOut = System.out;
        final ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
        final PrintStream printStream = new PrintStream(byteArrayOutputStream);
        System.setOut(printStream);
        try {
            Ideone.printStars(n);
        } finally {
            System.setOut(oldSystemOut);
            printStream.close();
        }

        final String expectedOutput = buildExpectedOutputString(expectedOutputLines);
        assertEquals(expectedOutput, byteArrayOutputStream.toString());
    }

    private static String buildExpectedOutputString(String[] expectedOutputLines) {
        final StringBuilder expectedOutputStringBuilder = new StringBuilder();
        for (String line : expectedOutputLines) {

            line = line.replaceAll("(.)", " $1");   // Add spaces

            expectedOutputStringBuilder.append(line);

//            final String NL = System.lineSeparator(); // Local system newline
            final String NL = "\n";     // Unix standard newline

            expectedOutputStringBuilder.append(NL);
        }
        return expectedOutputStringBuilder.toString();
    }

}