test/java/util/Map/Defaults.java

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rev 6858 : 8004518: Add in-place operations to Map
8010122: Add defaults for ConcurrentMap operations to Map
Reviewed-by: darcy, briangoetz, mduigou, dholmes, ulfzibis
Contributed-by: Doug Lea <dl at cs.oswego.edu>, Henry Jen <henry.jen@oracle.com>, Akhil Arora <akhil.arora@oracle.com>, Peter Levart <peter.levart@gmail.com>

@@ -21,167 +21,574 @@
  * questions.
  */
 
 /*
  * @test
- * @bug 8008785
- * @summary Ensure toArray() implementations return correct results.
+ * @bug 8010122 8004518
+ * @summary Test Map default methods
  * @author Mike Duigou
+ * @run testng Defaults
  */
-import java.util.*;
+import java.util.AbstractMap;
+import java.util.AbstractSet;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.EnumMap;
+import java.util.HashMap;
+import java.util.Hashtable;
+import java.util.IdentityHashMap;
+import java.util.Iterator;
+import java.util.LinkedHashMap;
+import java.util.Map;
+import java.util.TreeMap;
+import java.util.Set;
+import java.util.WeakHashMap;
+import java.util.concurrent.ConcurrentMap;
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.ConcurrentSkipListMap;
+import java.util.function.Supplier;
 
-public class ToArray {
+import org.testng.annotations.Test;
+import org.testng.annotations.DataProvider;
+import static org.testng.Assert.fail;
+import static org.testng.Assert.assertEquals;
+import static org.testng.Assert.assertTrue;
+import static org.testng.Assert.assertFalse;
+import static org.testng.Assert.assertNull;
+import static org.testng.Assert.assertSame;
+
+public class Defaults {
+
+    @Test(dataProvider = "Nulls Map<IntegerEnum,String>")
+    public void testGetOrDefaultNulls(String description, Map<IntegerEnum, String> map) {
+        assertTrue(map.containsKey(null), "null key absent");
+        assertNull(map.get(null), "value not null");
+        assertSame(map.get(null), map.getOrDefault(null, EXTRA_VALUE), "values should match");
+    }
+
+    @Test(dataProvider = "Map<IntegerEnum,String>")
+    public void testGetOrDefault(String description, Map<IntegerEnum, String> map) {
+        assertTrue(map.containsKey(KEYS[1]), "expected key missing");
+        assertSame(map.get(KEYS[1]), map.getOrDefault(KEYS[1], EXTRA_VALUE), "values should match");
+        assertFalse(map.containsKey(EXTRA_KEY), "expected absent key");
+        assertSame(map.getOrDefault(EXTRA_KEY, EXTRA_VALUE), EXTRA_VALUE, "value not returned as default");
+        assertNull(map.getOrDefault(EXTRA_KEY, null), "null not returned as default");
+    }
+
+    @Test(dataProvider = "R/W Nulls Map<IntegerEnum,String>")
+    public void testPutIfAbsentNulls(String description, Map<IntegerEnum, String> map) {
+        assertTrue(map.containsKey(null), "null key absent");
+        assertNull(map.get(null), "value not null");
+        assertNull(map.putIfAbsent(null, EXTRA_VALUE), "previous not null");
+        assertTrue(map.containsKey(null), "null key absent");
+        assertSame(map.get(null), EXTRA_VALUE, "unexpected value");
+        assertSame(map.putIfAbsent(null, null), EXTRA_VALUE, "previous not expected value");
+        assertTrue(map.containsKey(null), "null key absent");
+        assertSame(map.get(null), EXTRA_VALUE, "unexpected value");
+        assertSame(map.remove(null), EXTRA_VALUE, "removed unexpected value");
+
+        assertFalse(map.containsKey(null), description + ": key present after remove");
+        assertNull(map.putIfAbsent(null, null), "previous not null");
+        assertTrue(map.containsKey(null), "null key absent");
+        assertNull(map.get(null), "value not null");
+        assertNull(map.putIfAbsent(null, EXTRA_VALUE), "previous not null");
+        assertSame(map.get(null), EXTRA_VALUE, "value not expected");
+    }
+
+    @Test(dataProvider = "R/W Map<IntegerEnum,String>")
+    public void testPutIfAbsent(String description, Map<IntegerEnum, String> map) {
+        assertTrue(map.containsKey(KEYS[1]));
+        Object expected = map.get(KEYS[1]);
+        assertTrue(null == expected || expected == VALUES[1]);
+        assertSame(map.putIfAbsent(KEYS[1], EXTRA_VALUE), expected);
+        assertSame(map.get(KEYS[1]), expected);
+
+        assertFalse(map.containsKey(EXTRA_KEY));
+        assertSame(map.putIfAbsent(EXTRA_KEY, EXTRA_VALUE), null);
+        assertSame(map.get(EXTRA_KEY), EXTRA_VALUE);
+    }
+
+    @Test(dataProvider = "Nulls Map<IntegerEnum,String>")
+    public void testForEach(String description, Map<IntegerEnum, String> map) {
+        IntegerEnum[] EACH_KEY = new IntegerEnum[map.size()];
+
+        map.forEach((k, v) -> {
+            int idx = (null == k) ? 0 : k.ordinal(); // substitute for index.
+            assertNull(EACH_KEY[idx]);
+            EACH_KEY[idx] = (idx == 0) ? KEYS[0] : k; // substitute for comparison.
+            assertSame(v, map.get(k));
+        });
+
+        assertEquals(KEYS, EACH_KEY);
+    }
+
+    @Test(dataProvider = "R/W Nulls Map<IntegerEnum,String>")
+    public static void testRemoveNulls(String description, Map<IntegerEnum, String> map) {
+        assertTrue(map.containsKey(null), "null key absent");
+        assertNull(map.get(null), "value not null");
+        assertFalse(map.remove(null, EXTRA_VALUE), description);
+        assertTrue(map.containsKey(null));
+        assertNull(map.get(null));
+        assertTrue(map.remove(null, null));
+        assertFalse(map.containsKey(null));
+        assertNull(map.get(null));
+        assertFalse(map.remove(null, null));
+    }
+
+    @Test(dataProvider = "R/W Map<IntegerEnum,String>")
+    public static void testRemove(String description, Map<IntegerEnum, String> map) {
+        assertTrue(map.containsKey(KEYS[1]));
+        Object expected = map.get(KEYS[1]);
+        assertTrue(null == expected || expected == VALUES[1]);
+        assertFalse(map.remove(KEYS[1], EXTRA_VALUE), description);
+        assertSame(map.get(KEYS[1]), expected);
+        assertTrue(map.remove(KEYS[1], expected));
+        assertNull(map.get(KEYS[1]));
+        assertFalse(map.remove(KEYS[1], expected));
+
+        assertFalse(map.containsKey(EXTRA_KEY));
+        assertFalse(map.remove(EXTRA_KEY, EXTRA_VALUE));
+    }
+
+    @Test(dataProvider = "R/W Nulls Map<IntegerEnum,String>")
+    public void testReplaceKVNulls(String description, Map<IntegerEnum, String> map) {
+        assertTrue(map.containsKey(null), "null key absent");
+        assertNull(map.get(null), "value not null");
+        assertSame(map.replace(null, EXTRA_VALUE), null);
+        assertSame(map.get(null), EXTRA_VALUE);
+    }
+
+    @Test(dataProvider = "R/W Map<IntegerEnum,String>")
+    public void testReplaceKV(String description, Map<IntegerEnum, String> map) {
+        assertTrue(map.containsKey(KEYS[1]));
+        Object expected = map.get(KEYS[1]);
+        assertTrue(null == expected || expected == VALUES[1]);
+        assertSame(map.replace(KEYS[1], EXTRA_VALUE), expected);
+        assertSame(map.get(KEYS[1]), EXTRA_VALUE);
+
+        assertFalse(map.containsKey(EXTRA_KEY));
+        assertNull(map.replace(EXTRA_KEY, EXTRA_VALUE));
+        assertFalse(map.containsKey(EXTRA_KEY));
+        assertNull(map.get(EXTRA_KEY));
+        assertNull(map.put(EXTRA_KEY, EXTRA_VALUE));
+        assertSame(map.get(EXTRA_KEY), EXTRA_VALUE);
+        assertSame(map.replace(EXTRA_KEY, (String)expected), EXTRA_VALUE);
+        assertSame(map.get(EXTRA_KEY), expected);
+    }
+
+    @Test(dataProvider = "R/W Nulls Map<IntegerEnum,String>")
+    public void testReplaceKVVNulls(String description, Map<IntegerEnum, String> map) {
+        assertTrue(map.containsKey(null), "null key absent");
+        assertNull(map.get(null), "value not null");
+        assertFalse(map.replace(null, EXTRA_VALUE, EXTRA_VALUE));
+        assertNull(map.get(null));
+        assertTrue(map.replace(null, null, EXTRA_VALUE));
+        assertSame(map.get(null), EXTRA_VALUE);
+        assertTrue(map.replace(null, EXTRA_VALUE, EXTRA_VALUE));
+        assertSame(map.get(null), EXTRA_VALUE);
+    }
+
+    @Test(dataProvider = "R/W Map<IntegerEnum,String>")
+    public void testReplaceKVV(String description, Map<IntegerEnum, String> map) {
+        assertTrue(map.containsKey(KEYS[1]));
+        Object expected = map.get(KEYS[1]);
+        assertTrue(null == expected || expected == VALUES[1]);
+        assertFalse(map.replace(KEYS[1], EXTRA_VALUE, EXTRA_VALUE));
+        assertSame(map.get(KEYS[1]), expected);
+        assertTrue(map.replace(KEYS[1], (String)expected, EXTRA_VALUE));
+        assertSame(map.get(KEYS[1]), EXTRA_VALUE);
+        assertTrue(map.replace(KEYS[1], EXTRA_VALUE, EXTRA_VALUE));
+        assertSame(map.get(KEYS[1]), EXTRA_VALUE);
+
+        assertFalse(map.containsKey(EXTRA_KEY));
+        assertFalse(map.replace(EXTRA_KEY, EXTRA_VALUE, EXTRA_VALUE));
+        assertFalse(map.containsKey(EXTRA_KEY));
+        assertNull(map.get(EXTRA_KEY));
+        assertNull(map.put(EXTRA_KEY, EXTRA_VALUE));
+        assertTrue(map.containsKey(EXTRA_KEY));
+        assertSame(map.get(EXTRA_KEY), EXTRA_VALUE);
+        assertTrue(map.replace(EXTRA_KEY, EXTRA_VALUE, EXTRA_VALUE));
+        assertSame(map.get(EXTRA_KEY), EXTRA_VALUE);
+    }
+
+    @Test(dataProvider = "R/W Nulls Map<IntegerEnum,String>")
+    public void testComputeIfAbsentNulls(String description, Map<IntegerEnum, String> map) {
+        assertTrue(map.containsKey(null), "null key absent");
+        assertNull(map.get(null), "value not null");
+        assertSame(map.computeIfAbsent(null, (k) -> EXTRA_VALUE), EXTRA_VALUE, description);
+        assertSame(map.get(null), EXTRA_VALUE, description);
+    }
+
+    @Test(dataProvider = "R/W Map<IntegerEnum,String>")
+    public void testComputeIfAbsent(String description, Map<IntegerEnum, String> map) {
+        assertTrue(map.containsKey(KEYS[1]));
+        Object expected = map.get(KEYS[1]);
+        assertTrue(null == expected || expected == VALUES[1], description + String.valueOf(expected));
+        expected = (null == expected) ? EXTRA_VALUE : expected;
+        assertSame(map.computeIfAbsent(KEYS[1], (k) -> EXTRA_VALUE), expected, description);
+        assertSame(map.get(KEYS[1]), expected, description);
+
+        assertFalse(map.containsKey(EXTRA_KEY));
+        assertSame(map.computeIfAbsent(EXTRA_KEY, (k) -> EXTRA_VALUE), EXTRA_VALUE);
+        assertSame(map.get(EXTRA_KEY), EXTRA_VALUE);
+    }
+
+    @Test(dataProvider = "R/W Nulls Map<IntegerEnum,String>")
+    public void testComputeIfPresentNulls(String description, Map<IntegerEnum, String> map) {
+        assertTrue(map.containsKey(null));
+        assertNull(map.get(null));
+        assertSame(map.computeIfPresent(null, (k, v) -> {
+            fail();
+            return EXTRA_VALUE;
+        }), null, description);
+        assertTrue(map.containsKey(null));
+        assertSame(map.get(null), null, description);
+    }
+
+    @Test(dataProvider = "R/W Map<IntegerEnum,String>")
+    public void testComputeIfPresent(String description, Map<IntegerEnum, String> map) {
+        assertTrue(map.containsKey(KEYS[1]));
+        Object value = map.get(KEYS[1]);
+        assertTrue(null == value || value == VALUES[1], description + String.valueOf(value));
+        Object expected = (null == value) ? null : EXTRA_VALUE;
+        assertSame(map.computeIfPresent(KEYS[1], (k, v) -> {
+            assertSame(v, value);
+            return EXTRA_VALUE;
+        }), expected, description);
+        assertSame(map.get(KEYS[1]), expected, description);
 
+        assertFalse(map.containsKey(EXTRA_KEY));
+        assertSame(map.computeIfPresent(EXTRA_KEY, (k, v) -> {
+            fail();
+            return EXTRA_VALUE;
+        }), null);
+        assertFalse(map.containsKey(EXTRA_KEY));
+        assertSame(map.get(EXTRA_KEY), null);
+    }
+
+    @Test(dataProvider = "R/W Nulls Map<IntegerEnum,String>")
+    public void testComputeNulls(String description, Map<IntegerEnum, String> map) {
+        assertTrue(map.containsKey(null), "null key absent");
+        assertNull(map.get(null), "value not null");
+        assertSame(map.compute(null, (k, v) -> {
+            assertSame(k, null);
+            assertNull(v);
+            return EXTRA_VALUE;
+        }), EXTRA_VALUE, description);
+        assertTrue(map.containsKey(null));
+        assertSame(map.get(null), EXTRA_VALUE, description);
+        assertSame(map.remove(null), EXTRA_VALUE, "removed value not expected");
+        assertFalse(map.containsKey(null), "null key present");
+        assertSame(map.compute(null, (k, v) -> {
+            assertSame(k, null);
+            assertNull(v);
+            return null;
+        }), null, description);
+    }
+
+    @Test(dataProvider = "R/W Map<IntegerEnum,String>")
+    public void testCompute(String description, Map<IntegerEnum, String> map) {
+        assertTrue(map.containsKey(KEYS[1]));
+        Object value = map.get(KEYS[1]);
+        assertTrue(null == value || value == VALUES[1], description + String.valueOf(value));
+        assertSame(map.compute(KEYS[1], (k, v) -> {
+            assertSame(k, KEYS[1]);
+            assertSame(v, value);
+            return EXTRA_VALUE;
+        }), EXTRA_VALUE, description);
+        assertSame(map.get(KEYS[1]), EXTRA_VALUE, description);
+        assertNull(map.compute(KEYS[1], (k, v) -> {
+            assertSame(v, EXTRA_VALUE);
+            return null;
+        }), description);
+        assertFalse(map.containsKey(KEYS[1]));
+
+        assertFalse(map.containsKey(EXTRA_KEY));
+        assertSame(map.compute(EXTRA_KEY, (k, v) -> {
+            assertNull(v);
+            return EXTRA_VALUE;
+        }), EXTRA_VALUE);
+        assertTrue(map.containsKey(EXTRA_KEY));
+        assertSame(map.get(EXTRA_KEY), EXTRA_VALUE);
+    }
+
+
+    @Test(dataProvider = "R/W Nulls Map<IntegerEnum,String>")
+    public void testMergeNulls(String description, Map<IntegerEnum, String> map) {
+        assertTrue(map.containsKey(null), "null key absent");
+        assertNull(map.get(null), "value not null");
+        assertSame(map.merge(null, EXTRA_VALUE, (v, vv) -> {
+            assertNull(v);
+            assertSame(vv, EXTRA_VALUE);
+            return vv;
+        }), EXTRA_VALUE, description);
+        assertTrue(map.containsKey(null));
+        assertSame(map.get(null), EXTRA_VALUE, description);
+    }
+
+    @Test(dataProvider = "R/W Map<IntegerEnum,String>")
+    public void testMerge(String description, Map<IntegerEnum, String> map) {
+        assertTrue(map.containsKey(KEYS[1]));
+        Object value = map.get(KEYS[1]);
+        assertTrue(null == value || value == VALUES[1], description + String.valueOf(value));
+        assertSame(map.merge(KEYS[1], EXTRA_VALUE, (v, vv) -> {
+            assertSame(v, value);
+            assertSame(vv, EXTRA_VALUE);
+            return vv;
+        }), EXTRA_VALUE, description);
+        assertSame(map.get(KEYS[1]), EXTRA_VALUE, description);
+        assertNull(map.merge(KEYS[1], EXTRA_VALUE, (v, vv) -> {
+            assertSame(v, EXTRA_VALUE);
+            assertSame(vv, EXTRA_VALUE);
+            return null;
+        }), description);
+        assertFalse(map.containsKey(KEYS[1]));
+
+        assertFalse(map.containsKey(EXTRA_KEY));
+        assertSame(map.merge(EXTRA_KEY, EXTRA_VALUE, (v, vv) -> {
+            assertNull(v);
+            assertSame(vv, EXTRA_VALUE);
+            return EXTRA_VALUE;
+        }), EXTRA_VALUE);
+        assertTrue(map.containsKey(EXTRA_KEY));
+        assertSame(map.get(EXTRA_KEY), EXTRA_VALUE);
+    }
+
+    enum IntegerEnum {
+
+        e0, e1, e2, e3, e4, e5, e6, e7, e8, e9,
+        e10, e11, e12, e13, e14, e15, e16, e17, e18, e19,
+        e20, e21, e22, e23, e24, e25, e26, e27, e28, e29,
+        e30, e31, e32, e33, e34, e35, e36, e37, e38, e39,
+        e40, e41, e42, e43, e44, e45, e46, e47, e48, e49,
+        e50, e51, e52, e53, e54, e55, e56, e57, e58, e59,
+        e60, e61, e62, e63, e64, e65, e66, e67, e68, e69,
+        e70, e71, e72, e73, e74, e75, e76, e77, e78, e79,
+        e80, e81, e82, e83, e84, e85, e86, e87, e88, e89,
+        e90, e91, e92, e93, e94, e95, e96, e97, e98, e99,
+        EXTRA_KEY;
+        public static final int SIZE = values().length;
+    };
+    private static final int TEST_SIZE = IntegerEnum.SIZE - 1;
     /**
-     * Number of elements per map.
+     * Realized keys ensure that there is always a hard ref to all test objects.
      */
-    private static final int TEST_SIZE = 5000;
-
-    private static void realMain(String[] args) throws Throwable {
-        Map<Integer, Long>[] maps = (Map<Integer, Long>[]) new Map[]{
-                    new HashMap<>(),
-                    new Hashtable<>(),
-                    new IdentityHashMap<>(),
-                    new LinkedHashMap<>(),
-                    new TreeMap<>(),
-                    new WeakHashMap<>(),
-                    new ConcurrentHashMap<>(),
-                    new ConcurrentSkipListMap<>()
-                };
+    private static final IntegerEnum[] KEYS = new IntegerEnum[TEST_SIZE];
+    /**
+     * Realized values ensure that there is always a hard ref to all test
+     * objects.
+     */
+    private static final String[] VALUES = new String[TEST_SIZE];
 
-        // for each map type.
-        for (Map<Integer, Long> map : maps) {
-             try {
-                testMap(map);
-             } catch(Exception all) {
-                unexpected("Failed for " + map.getClass().getName(), all);
-             }
+    static {
+        IntegerEnum[] keys = IntegerEnum.values();
+        for (int each = 0; each < TEST_SIZE; each++) {
+            KEYS[each] = keys[each];
+            VALUES[each] = String.valueOf(each);
         }
     }
+    private static final IntegerEnum EXTRA_KEY = IntegerEnum.EXTRA_KEY;
+    private static final String EXTRA_VALUE = String.valueOf(TEST_SIZE);
 
-    private static final Integer[] KEYS = new Integer[TEST_SIZE];
+    @DataProvider(name = "Map<IntegerEnum,String>", parallel = true)
+    public static Iterator<Object[]> allNullsMapProvider() {
+        return makeAllMaps().iterator();
+    }
 
-    private static final Long[] VALUES = new Long[TEST_SIZE];
+    @DataProvider(name = "Nulls Map<IntegerEnum,String>", parallel = true)
+    public static Iterator<Object[]> allMapProvider() {
+        return makeRWMaps(true).iterator();
+    }
 
-    static {
-        for (int each = 0; each < TEST_SIZE; each++) {
-            KEYS[each]   = Integer.valueOf(each);
-            VALUES[each] = Long.valueOf(each + TEST_SIZE);
+    @DataProvider(name = "R/W Map<IntegerEnum,String>", parallel = true)
+    public static Iterator<Object[]> rwMapProvider() {
+        return makeRWMapsNoNulls().iterator();
         }
+
+    @DataProvider(name = "R/W Nulls Map<IntegerEnum,String>", parallel = true)
+    public static Iterator<Object[]> rwNullsMapProvider() {
+        return makeRWMaps(true).iterator();
     }
 
+    private static Collection<Object[]> makeAllMapsNoNulls() {
+        Collection<Object[]> all = new ArrayList<>();
 
-    private static void testMap(Map<Integer, Long> map) {
-        System.out.println("Testing " + map.getClass());
-        System.out.flush();
+        all.addAll(makeRWMaps(false));
+        all.addAll(makeRWNoNullsMaps());
+        all.addAll(makeROMaps(false));
 
-        // Fill the map
-        for (int each = 0; each < TEST_SIZE; each++) {
-            map.put(KEYS[each], VALUES[each]);
+        return all;
         }
 
-        // check the keys
-        Object[] keys = map.keySet().toArray();
-        Arrays.sort(keys);
+    private static Collection<Object[]> makeRWMapsNoNulls() {
+        Collection<Object[]> all = new ArrayList<>();
+
+        all.addAll(makeRWMaps(false));
+        all.addAll(makeRWNoNullsMaps());
 
-        for(int each = 0; each < TEST_SIZE; each++) {
-            check( "unexpected key", keys[each] == KEYS[each]);
+        return all;
         }
 
-        // check the values
-        Object[] values = map.values().toArray();
-        Arrays.sort(values);
+    private static Collection<Object[]> makeAllMaps() {
+        Collection<Object[]> all = new ArrayList<>();
 
-        for(int each = 0; each < TEST_SIZE; each++) {
-            check( "unexpected value", values[each] == VALUES[each]);
+        all.addAll(makeROMaps(false));
+        all.addAll(makeRWMaps(false));
+        all.addAll(makeRWNoNullsMaps());
+        all.addAll(makeRWMaps(true));
+        all.addAll(makeROMaps(true));
+
+        return all;
         }
 
-        // check the entries
-        Map.Entry<Integer,Long>[] entries = map.entrySet().toArray(new Map.Entry[TEST_SIZE]);
-        Arrays.sort( entries,new Comparator<Map.Entry<Integer,Long>>() {
-                public int compare(Map.Entry<Integer,Long> o1, Map.Entry<Integer,Long> o2) {
-                        return o1.getKey().compareTo(o2.getKey());
-                }});
+    private static Collection<Object[]> makeAllRWMaps() {
+        Collection<Object[]> all = new ArrayList<>();
+
+        all.addAll(makeRWMaps(false));
+        all.addAll(makeRWNoNullsMaps());
+        all.addAll(makeRWMaps(true));
 
-        for(int each = 0; each < TEST_SIZE; each++) {
-            check( "unexpected entry", entries[each].getKey() == KEYS[each] && entries[each].getValue() == VALUES[each]);
+        return all;
         }
+
+    private static Collection<Object[]> makeRWMaps(boolean nulls) {
+        return Arrays.asList(
+            new Object[]{"HashMap", makeMap(HashMap::new, nulls)},
+            new Object[]{"IdentityHashMap", makeMap(IdentityHashMap::new, nulls)},
+            new Object[]{"LinkedHashMap", makeMap(LinkedHashMap::new, nulls)},
+            new Object[]{"WeakHashMap", makeMap(WeakHashMap::new, nulls)},
+            new Object[]{"Collections.checkedMap(HashMap)", Collections.checkedMap(makeMap(HashMap::new, nulls), IntegerEnum.class, String.class)},
+            new Object[]{"Collections.synchronizedMap(HashMap)", Collections.synchronizedMap(makeMap(HashMap::new, nulls))},
+            new Object[]{"ExtendsAbstractMap", makeMap(ExtendsAbstractMap::new, nulls)});
     }
 
-    //--------------------- Infrastructure ---------------------------
-    static volatile int passed = 0, failed = 0;
+    private static Collection<Object[]> makeRWNoNullsMaps() {
+        return Arrays.asList(
+            // null hostile
+            new Object[]{"EnumMap", makeMap(() -> new EnumMap(IntegerEnum.class), false)},
+            new Object[]{"Hashtable", makeMap(Hashtable::new, false)},
+            new Object[]{"TreeMap", makeMap(TreeMap::new, false)},
+            new Object[]{"ConcurrentHashMap", makeMap(ConcurrentHashMap::new, false)},
+            new Object[]{"ConcurrentSkipListMap", makeMap(ConcurrentSkipListMap::new, false)},
+            new Object[]{"Collections.checkedMap(ConcurrentHashMap)", Collections.checkedMap(makeMap(ConcurrentHashMap::new, false), IntegerEnum.class, String.class)},
+            new Object[]{"Collections.synchronizedMap(EnumMap)", Collections.synchronizedMap(makeMap(() -> new EnumMap(IntegerEnum.class), false))},
+            new Object[]{"ImplementsConcurrentMap", makeMap(ImplementsConcurrentMap::new, false)});
+    }
 
-    static void pass() {
-        passed++;
+    private static Collection<Object[]> makeROMaps(boolean nulls) {
+        return Arrays.asList(new Object[][]{
+            new Object[]{"Collections.unmodifiableMap(HashMap)", Collections.unmodifiableMap(makeMap(HashMap::new, nulls))}
+        });
     }
 
-    static void fail() {
-        failed++;
-        (new Error("Failure")).printStackTrace(System.err);
+    private static Map<IntegerEnum, String> makeMap(Supplier<Map<IntegerEnum, String>> supplier, boolean nulls) {
+        Map<IntegerEnum, String> result = supplier.get();
+
+        for (int each = 0; each < TEST_SIZE; each++) {
+            if (nulls) {
+                result.put((each == 0) ? null : KEYS[each], null);
+            } else {
+                result.put(KEYS[each], VALUES[each]);
+            }
     }
 
-    static void fail(String msg) {
-        failed++;
-        (new Error("Failure: " + msg)).printStackTrace(System.err);
+        return result;
     }
 
-    static void abort() {
-        fail();
-        System.exit(1);
+    public interface Thrower<T extends Throwable> {
+
+        public void run() throws T;
     }
 
-    static void abort(String msg) {
-        fail(msg);
-        System.exit(1);
+    public static <T extends Throwable> void assertThrows(Thrower<T> thrower, Class<T> throwable) {
+        assertThrows(thrower, throwable, null);
     }
 
-    static void unexpected(String msg, Throwable t) {
-        System.err.println("Unexpected: " + msg);
-        unexpected(t);
+    public static <T extends Throwable> void assertThrows(Thrower<T> thrower, Class<T> throwable, String message) {
+        Throwable result;
+        try {
+            thrower.run();
+            result = null;
+        } catch (Throwable caught) {
+            result = caught;
     }
 
-    static void unexpected(Throwable t) {
-        failed++;
-        t.printStackTrace(System.err);
+        assertInstance(result, throwable,
+            (null != message)
+            ? message
+            : "Failed to throw " + throwable.getCanonicalName());
     }
 
-    static void check(boolean cond) {
-        if (cond) {
-            pass();
-        } else {
-            fail();
+    public static <T> void assertInstance(T actual, Class<? extends T> expected) {
+        assertInstance(expected.isInstance(actual), null);
         }
+
+    public static <T> void assertInstance(T actual, Class<? extends T> expected, String message) {
+        assertTrue(expected.isInstance(actual), message);
     }
 
-    static void check(String desc, boolean cond) {
-        if (cond) {
-            pass();
-        } else {
-            fail(desc);
+    /**
+     * A simple mutable map implementation that provides only default
+     * implementations of all methods. ie. none of the Map interface default
+     * methods have overridden implementations.
+     *
+     * @param <K> Type of keys
+     * @param <V> Type of values
+     */
+    public static class ExtendsAbstractMap<M extends Map<K,V>, K, V> extends AbstractMap<K, V> {
+
+        protected final M map;
+
+        public ExtendsAbstractMap() { this( (M) new HashMap<K,V>()); }
+
+        protected ExtendsAbstractMap(M map) { this.map = map; }
+
+        public Set<Map.Entry<K, V>> entrySet() {
+            return new AbstractSet<Map.Entry<K, V>>() {
+                public int size() {
+                    return map.size();
         }
+
+                public Iterator<Map.Entry<K,V>> iterator() {
+                    final Iterator<Map.Entry<K,V>> source = map.entrySet().iterator();
+                    return new Iterator<Map.Entry<K,V>>() {
+                       public boolean hasNext() { return source.hasNext(); }
+                       public Map.Entry<K,V> next() { return source.next(); }
+                       public void remove() { source.remove(); }
+                    };
     }
 
-    static void equal(Object x, Object y) {
-        if (Objects.equals(x, y)) {
-            pass();
-        } else {
-            fail(x + " not equal to " + y);
+                public boolean add(Map.Entry<K,V> e) {
+                    return map.entrySet().add(e);
         }
+            };
     }
 
-    public static void main(String[] args) throws Throwable {
-        Thread.currentThread().setName(ToArray.class.getName());
-//        Thread.currentThread().setPriority(Thread.MAX_PRIORITY);
-        try {
-            realMain(args);
-        } catch (Throwable t) {
-            unexpected(t);
+        public V put(K key, V value) {
+            return map.put(key, value);
         }
-
-        System.out.printf("%nPassed = %d, failed = %d%n%n", passed, failed);
-        if (failed > 0) {
-            throw new Error("Some tests failed");
         }
+
+    /**
+     * A simple mutable concurrent map implementation that provides only default
+     * implementations of all methods. ie. none of the ConcurrentMap interface
+     * default methods have overridden implementations.
+     *
+     * @param <K> Type of keys
+     * @param <V> Type of values
+     */
+    public static class ImplementsConcurrentMap<K, V> extends ExtendsAbstractMap<ConcurrentMap<K,V>, K, V> implements ConcurrentMap<K,V> {
+        public ImplementsConcurrentMap() { super(new ConcurrentHashMap<K,V>()); }
+
+        // ConcurrentMap reabstracts these methods
+
+        public V replace(K k, V v) { return map.replace(k, v); };
+
+        public boolean replace(K k, V v, V vv) { return map.replace(k, v, vv); };
+
+        public boolean remove(Object k, Object v) { return map.remove(k, v); }
+
+        public V putIfAbsent(K k, V v) { return map.putIfAbsent(k, v); }
     }
 }