SarathKumarMca_SobhanThakur_Test

import junit.framework.TestCase;

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.io.PrintStream;

public class SarathKumarMca_SobhanThakur_Test extends TestCase {

    private static final String NL = System.getProperty("line.separator");

    public void test0() throws IOException {
        final String outputLines = call_printNumberTriangle(0);

        assertEquals("", outputLines);
    }

    public void test1() throws IOException {
        final String outputLines = call_printNumberTriangle(1);

        assertEquals(""
                        + "1 " + NL
                ,
                outputLines);
    }

    public void test2() throws IOException {
        final String outputLines = call_printNumberTriangle(2);

        assertEquals(""
                        + "1 " + NL
                        + "3 2 " + NL
                ,
                outputLines);
    }

    public void test4() throws IOException {
        final String outputLines = call_printNumberTriangle(4);

        assertEquals(""
                        + "1 " + NL
                        + "3 2 " + NL
                        + "4 5 6 " + NL
                        + "10 9 8 7 " + NL
                ,
                outputLines);
    }

    public void test5() throws IOException {
        final String outputLines = call_printNumberTriangle(5);

        assertEquals(""
                        + "1 " + NL
                        + "3 2 " + NL
                        + "4 5 6 " + NL
                        + "10 9 8 7 " + NL
                        + "11 12 13 14 15 " + NL
                ,
                outputLines);
    }

    public void test10() throws IOException {
        final String outputLines = call_printNumberTriangle(10);

        assertEquals(""
                        + "1 " + NL
                        + "3 2 " + NL
                        + "4 5 6 " + NL
                        + "10 9 8 7 " + NL
                        + "11 12 13 14 15 " + NL
                        + "21 20 19 18 17 16 " + NL
                        + "22 23 24 25 26 27 28 " + NL
                        + "36 35 34 33 32 31 30 29 " + NL
                        + "37 38 39 40 41 42 43 44 45 " + NL
                        + "55 54 53 52 51 50 49 48 47 46 " + NL
                ,
                outputLines);
    }

    /**
     * Call the <code>printNumberTriangle</code> function, and return a <code>String</code> value, of the
     * <code>System.out.println</code> calls of the code.
     */
    private String call_printNumberTriangle(final int numberOfOutputRows) throws IOException {
        final PrintStream oldSystemOut = System.out;
        final OutputStream outputStream = new ByteArrayOutputStream();
        System.setOut(new PrintStream(outputStream));
        try {

            SarathKumarMca_SobhanThakur.printNumberTriangle(numberOfOutputRows);

        } finally {
            System.setOut(oldSystemOut);
        }
        outputStream.flush();
        outputStream.close();

        return outputStream.toString();
    }

}