assertEquals("foo", sb.toString());  sb.append((StrBuilder) null, 0, 1);
    public void testAppend_StrBuilder_int_int() {        StrBuilder sb = new StrBuilder();                sb.append(new StrBuilder("foo"), 0, 3);        assertEquals("foo", sb.toString());        sb.append((StrBuilder) null, 0, 1);        assertEquals("foo", sb.toString());        try {            sb.append(new StrBuilder("bar"), -1, 1);            fail("append(char[], -1,) expected IndexOutOfBoundsException");        } catch (IndexOutOfBoundsException e) {            // expected        }        try {            sb.append(new StrBuilder("bar"), 3, 1);            fail("append(char[], 3,) expected IndexOutOfBoundsException");        } catch (IndexOutOfBoundsException e) {            // expected        }        try {            sb.append(new StrBuilder("bar"), 1, -1);            fail("append(char[],, -1) expected IndexOutOfBoundsException");        } catch (IndexOutOfBoundsException e) {            // expected        }        try {            sb.append(new StrBuilder("bar"), 1, 3);            fail("append(char[], 1, 3) expected IndexOutOfBoundsException");        } catch (IndexOutOfBoundsException e) {            // expected        }        try {            sb.append(new StrBuilder("bar"), -1, 3);            fail("append(char[], -1, 3) expected IndexOutOfBoundsException");        } catch (IndexOutOfBoundsException e) {            // expected        }        try {            sb.append(new StrBuilder("bar"), 4, 0);            fail("append(char[], 4, 0) expected IndexOutOfBoundsException");        } catch (IndexOutOfBoundsException e) {            // expected        }        sb.append(new StrBuilder("bar"), 3, 0);        assertEquals("foo", sb.toString());        sb.append(new StrBuilder("abcbardef"), 3, 3);        assertEquals("foobar", sb.toString());    }