public final void testNonBlockingIdentityHashMapSize() {
    NonBlockingIdentityHashMap<Long, String> items = new NonBlockingIdentityHashMap<Long, String>();
    items.put(Long.valueOf(100), "100");
    items.put(Long.valueOf(101), "101");

    assertEquals("keySet().size()", 2, items.keySet().size());
    assertTrue("keySet().contains(100)", items.keySet().contains(Long.valueOf(100)));
    assertTrue("keySet().contains(101)", items.keySet().contains(Long.valueOf(101)));

    assertEquals("values().size()", 2, items.values().size());
    assertTrue("values().contains(\"100\")", items.values().contains("100"));
    assertTrue("values().contains(\"101\")", items.values().contains("101"));

    assertEquals("entrySet().size()", 2, items.entrySet().size());
    boolean found100 = false;
    boolean found101 = false;
    for (Entry<Long, String> entry : items.entrySet()) {
      if (entry.getKey().equals(Long.valueOf(100))) {
        assertEquals("entry[100].getValue()==\"100\"", "100", entry.getValue());
        found100 = true;
      } else if (entry.getKey().equals(Long.valueOf(101))) {
        assertEquals("entry[101].getValue()==\"101\"", "101", entry.getValue());
        found101 = true;
      }
    }
    assertTrue("entrySet().contains([100])", found100);
    assertTrue("entrySet().contains([101])", found101);
  }
  // Do some simple concurrent testing
  public void testConcurrentSimple() throws InterruptedException {
    final NonBlockingIdentityHashMap<String, String> nbhm =
        new NonBlockingIdentityHashMap<String, String>();
    final String[] keys = new String[20000];
    for (int i = 0; i < 20000; i++) keys[i] = "k" + i;

    // In 2 threads, add & remove even & odd elements concurrently
    Thread t1 =
        new Thread() {
          public void run() {
            work_helper(nbhm, "T1", 1, keys);
          }
        };
    t1.start();
    work_helper(nbhm, "T0", 0, keys);
    t1.join();

    // In the end, all members should be removed
    StringBuffer buf = new StringBuffer();
    buf.append("Should be emptyset but has these elements: {");
    boolean found = false;
    for (String x : nbhm.keySet()) {
      buf.append(" ").append(x);
      found = true;
    }
    if (found) System.out.println(buf + " }");
    assertThat("concurrent size=0", nbhm.size(), is(0));
    for (String x : nbhm.keySet()) {
      assertTrue("No elements so never get here", false);
    }
  }
  public void testIteration() {
    assertTrue(_nbhm.isEmpty());
    assertThat(_nbhm.put("k1", "v1"), nullValue());
    assertThat(_nbhm.put("k2", "v2"), nullValue());

    String str1 = "";
    for (Iterator<Map.Entry<String, String>> i = _nbhm.entrySet().iterator(); i.hasNext(); ) {
      Map.Entry<String, String> e = i.next();
      str1 += e.getKey();
    }
    assertThat("found all entries", str1, anyOf(is("k1k2"), is("k2k1")));

    String str2 = "";
    for (Iterator<String> i = _nbhm.keySet().iterator(); i.hasNext(); ) {
      String key = i.next();
      str2 += key;
    }
    assertThat("found all keys", str2, anyOf(is("k1k2"), is("k2k1")));

    String str3 = "";
    for (Iterator<String> i = _nbhm.values().iterator(); i.hasNext(); ) {
      String val = i.next();
      str3 += val;
    }
    assertThat("found all vals", str3, anyOf(is("v1v2"), is("v2v1")));

    assertThat(
        "toString works", _nbhm.toString(), anyOf(is("{k1=v1, k2=v2}"), is("{k2=v2, k1=v1}")));
  }
 // Check all iterators for correct size counts
 private void checkSizes(int expectedSize) {
   assertEquals("size()", _nbhm.size(), expectedSize);
   Collection<String> vals = _nbhm.values();
   checkSizes("values()", vals.size(), vals.iterator(), expectedSize);
   Set<String> keys = _nbhm.keySet();
   checkSizes("keySet()", keys.size(), keys.iterator(), expectedSize);
   Set<Entry<String, String>> ents = _nbhm.entrySet();
   checkSizes("entrySet()", ents.size(), ents.iterator(), expectedSize);
 }
  public void testIterationBig() {
    final int CNT = 10000;
    String[] keys = new String[CNT];
    String[] vals = new String[CNT];
    assertThat(_nbhm.size(), is(0));
    for (int i = 0; i < CNT; i++) _nbhm.put(keys[i] = ("k" + i), vals[i] = ("v" + i));
    assertThat(_nbhm.size(), is(CNT));

    int sz = 0;
    int sum = 0;
    for (String s : _nbhm.keySet()) {
      sz++;
      assertThat("", s.charAt(0), is('k'));
      int x = Integer.parseInt(s.substring(1));
      sum += x;
      assertTrue(x >= 0 && x <= (CNT - 1));
    }
    assertThat("Found 10000 ints", sz, is(CNT));
    assertThat("Found all integers in list", sum, is(CNT * (CNT - 1) / 2));

    assertThat("can remove 3", _nbhm.remove(keys[3]), is(vals[3]));
    assertThat("can remove 4", _nbhm.remove(keys[4]), is(vals[4]));
    sz = 0;
    sum = 0;
    for (String s : _nbhm.keySet()) {
      sz++;
      assertThat("", s.charAt(0), is('k'));
      int x = Integer.parseInt(s.substring(1));
      sum += x;
      assertTrue(x >= 0 && x <= (CNT - 1));
      String v = _nbhm.get(s);
      assertThat("", v.charAt(0), is('v'));
      assertThat("", s.substring(1), is(v.substring(1)));
    }
    assertThat("Found " + (CNT - 2) + " ints", sz, is(CNT - 2));
    assertThat("Found all integers in list", sum, is(CNT * (CNT - 1) / 2 - (3 + 4)));
  }