*** Test 1 - offer/poll ***
size()=16: x, t, t, s, r, o, o, o, n, m, i, g, e, a, a, a

*** Test 2 - iterator, contains ***
size=16: x, t, t, s, r, o, o, o, n, m, i, g, e, a, a, a
contains('a')=true
contains('b')=false
contains('c')=false
contains('d')=false
contains('e')=true
contains('f')=false
contains('g')=true
contains('h')=false
contains('i')=true
contains('j')=false
contains('k')=false
contains('l')=false
contains('m')=true
contains('n')=true
contains('o')=true
contains('p')=false
contains('q')=false
contains('r')=true
contains('s')=true
contains('t')=true
contains('u')=false
contains('v')=false
contains('w')=false
contains('x')=true
contains('y')=false
contains('z')=false

*** Test 3 - offer, poll, clear, peek ***
offer('x')
offer('a')
offer('s')
offer('y')
offer('d')
size=5: y, x, s, d, a
clear()
offer('a')
offer('b')
poll()=b
peek()=a
offer('c')
offer('z')
offer('c')
offer('d')
size=5: z, d, c, c, a
remove('c')=true
remove('z')=true
size=3: d, c, a

*** Test 4 - Aufgabenstellung ***
size=5: x, t, s, o, g

*** Test 5 - illegal arguments ***
offer('1'): java.lang.IllegalArgumentException
contains('1'): java.lang.IllegalArgumentException
remove('1'): java.lang.IllegalArgumentException