checkLineCol(r, lineNum, colNum) ;
assertEquals('1', r.readChar()) ;
checkLineCol(r, lineNum, colNum) ; // Unmoved.
r.pushbackChar('2') ;
r.pushbackChar('3') ;
checkLineCol(r, lineNum, colNum) ; // Unmoved.
assertEquals('3', r.peekChar()) ;
contains(r, "320") ;
}