angabe ue09

uebung09/test/iterator/Array2dIteratorTest.java

@@ -0,0 +1,43 @@
+package iterator;
+
+import org.junit.Test;
+
+import java.util.Iterator;
+import java.util.NoSuchElementException;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertThrows;
+import static org.junit.Assert.assertTrue;
+
+public class Array2dIteratorTest {
+    @Test
+    public void testArray2dIterator() {
+        final String[][] array = {{}, {"foo", "bar"}, {"baz"}, {}};
+        final Iterator<String> it = new Array2dIterator<>(array);
+        assertTrue(it.hasNext());
+        assertEquals("foo", it.next());
+        assertTrue(it.hasNext());
+        assertEquals("bar", it.next());
+        assertTrue(it.hasNext());
+        assertEquals("baz", it.next());
+        assertFalse(it.hasNext());
+        assertThrows(NoSuchElementException.class, it::next);
+    }
+
+    @Test
+    public void testArray2dIteratorOnlyEmpty() {
+        final String[][] array = {{}, {}, {}};
+        final Iterator<String> it = new Array2dIterator<>(array);
+        assertFalse(it.hasNext());
+        assertThrows(NoSuchElementException.class, it::next);
+    }
+
+    @Test
+    public void testArray2dIteratorEmpty() {
+        final String[][] array = {};
+        final Iterator<String> it = new Array2dIterator<>(array);
+        assertFalse(it.hasNext());
+        assertThrows(NoSuchElementException.class, it::next);
+    }
+}

uebung09/test/iterator/SkipNullIteratorTest.java

@@ -0,0 +1,122 @@
+package iterator;
+
+import org.junit.Test;
+
+import java.util.Iterator;
+import java.util.NoSuchElementException;
+
+import static java.util.Arrays.asList;
+import static java.util.Collections.emptyList;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertThrows;
+import static org.junit.Assert.assertTrue;
+
+public class SkipNullIteratorTest {
+    @Test
+    public void testEmpty() {
+        final Iterator<Object> it = new SkipNullIterator<>(emptyList().iterator());
+        assertFalse(it.hasNext());
+        assertThrows(NoSuchElementException.class, it::next);
+    }
+
+    @Test
+    public void testNull() {
+        final Iterator<Object> it = new SkipNullIterator<>(asList(null, null).iterator());
+        assertFalse(it.hasNext());
+        assertThrows(NoSuchElementException.class, it::next);
+    }
+
+    @Test
+    public void testNonNull() {
+        final Iterator<String> it = new SkipNullIterator<>(asList("foo").iterator());
+        assertTrue(it.hasNext());
+        assertEquals("foo", it.next());
+        assertFalse(it.hasNext());
+        assertThrows(NoSuchElementException.class, it::next);
+    }
+
+    @Test
+    public void testMixed() {
+        final Iterator<String> it = new SkipNullIterator<>(asList(null, "foo", null).iterator());
+        assertTrue(it.hasNext());
+        assertEquals("foo", it.next());
+        assertFalse(it.hasNext());
+        assertThrows(NoSuchElementException.class, it::next);
+    }
+
+    @Test
+    public void testMixed2() {
+        final Iterator<String> oriIt = asList("a", "b", null, "c").iterator();
+        Iterator<String> it = new SkipNullIterator<>(oriIt);
+        assertTrue(it.hasNext());
+        assertEquals("a", it.next());
+        assertTrue(it.hasNext());
+        assertEquals("b", it.next());
+        assertTrue(it.hasNext());
+        assertEquals("c", it.next());
+        assertFalse(it.hasNext());
+        assertThrows(NoSuchElementException.class, it::next);
+    }
+
+    @Test
+    public void testDontCallInCtor() {
+        final Iterator<String> dontCallNext = new Iterator<>() {
+            @Override
+            public boolean hasNext() {
+                throw new RuntimeException();
+            }
+
+            @Override
+            public String next() {
+                throw new RuntimeException();
+            }
+        };
+
+        new SkipNullIterator<>(dontCallNext);
+    }
+
+    @Test
+    public void testSkipNullIteratorInfinity() {
+        final Iterator<String> oriIt = new Iterator<>() {
+            @Override
+            public boolean hasNext() {
+                return true;
+            }
+
+            @Override
+            public String next() {
+                return "infinity";
+            }
+        };
+
+        final Iterator<String> it = new SkipNullIterator<>(oriIt);
+        for (int i = 0; i < 1000; i++) {
+            assertTrue(it.hasNext());
+            assertEquals("infinity", it.next());
+        }
+    }
+
+    @Test
+    public void testPathological() {
+        final Iterator<String> oriIt = new Iterator<>() {
+            private int ctr;
+
+            @Override
+            public boolean hasNext() {
+                return true;
+            }
+
+            @Override
+            public String next() {
+                return ctr++ > 100000 ? "infinity" : null;
+            }
+        };
+
+        final Iterator<String> it = new SkipNullIterator<>(oriIt);
+        for (int i = 0; i < 1000; i++) {
+            assertTrue(it.hasNext());
+            assertEquals("infinity", it.next());
+        }
+    }
+}