1 files changed, 126 insertions, 0 deletions
diff --git a/guava-tests/test/com/google/common/collect/TransformedSetTest.java b/guava-tests/test/com/google/common/collect/TransformedSetTest.java
new file mode 100644
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+++ b/guava-tests/test/com/google/common/collect/TransformedSetTest.java
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+/*
+ * Copyright (C) 2011 The Guava Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.google.common.collect;
+
+import com.google.common.annotations.GwtCompatible;
+import com.google.common.annotations.GwtIncompatible;
+import com.google.common.collect.testing.SampleElements;
+import com.google.common.collect.testing.SetTestSuiteBuilder;
+import com.google.common.collect.testing.TestSetGenerator;
+import com.google.common.collect.testing.features.CollectionFeature;
+import com.google.common.collect.testing.features.CollectionSize;
+import com.google.common.collect.testing.features.SetFeature;
+
+import junit.framework.TestCase;
+import junit.framework.TestSuite;
+
+import java.util.Arrays;
+import java.util.List;
+import java.util.Set;
+
+/**
+ * Tests for {@link Sets#transform(Set, Sets.InvertibleFunction)}.
+ * 
+ * @author Dimitris Andreou
+ */
+@GwtCompatible(emulated = true)
+public class TransformedSetTest extends TestCase {
+  // Negates each integer. This is a true bijection, even considering MIN_VALUE
+  private static final Sets.InvertibleFunction<Integer, Integer> integerBijection = 
+      new Sets.InvertibleFunction<Integer, Integer>() {
+        @Override public Integer apply(Integer integer) {
+          return integer != null ? -integer : null;
+        }
+
+        @Override
+        public Integer invert(Integer integer) {
+          return integer != null ? -integer : null;
+        }
+      };
+
+  @GwtIncompatible("suite")
+  public static TestSuite suite() {
+    TestSuite suite = new TestSuite();
+    suite.addTest(SetTestSuiteBuilder
+        .using(new TransformedIntegerSetGenerator())
+        .named("TransformedSet")
+        .withFeatures(
+        SetFeature.GENERAL_PURPOSE,
+        CollectionFeature.ALLOWS_NULL_VALUES,
+        CollectionSize.SEVERAL)
+      .createTestSuite());
+    return suite;
+  }
+  
+  public void testSimpleCases() {
+    Set<Integer> original = Sets.newHashSet(0, 1, 2, 3);
+    Set<Integer> transformed = Sets.transform(original, integerBijection);
+    
+    assertEquals(ImmutableSet.of(0, -1, -2, -3), transformed);
+    
+    // adding/removing to the original, see if transformed is affected
+    assertTrue(original.remove(2));
+    assertTrue(original.add(4));
+    assertEquals(ImmutableSet.of(0,  1,  3,  4), original);
+    assertEquals(ImmutableSet.of(0, -1, -3, -4), transformed);
+    
+    // adding/removing to the transformed, see if original is affected
+    assertTrue(transformed.remove(-1));
+    assertTrue(transformed.add(-5));
+    assertEquals(ImmutableSet.of(0, -3, -4, -5), transformed);
+    assertEquals(ImmutableSet.of(0,  3,  4,  5), original);
+    
+    // redoing the same actions as above; no effect
+    assertFalse(transformed.remove(-1));
+    assertFalse(transformed.add(-5));
+    
+    // they should always have the same size
+    assertEquals(original.size(), transformed.size());
+    
+    transformed.clear();
+    assertTrue(original.isEmpty());
+    assertTrue(transformed.isEmpty());
+  }
+
+  public static class TransformedIntegerSetGenerator implements TestSetGenerator<Integer> {
+    @Override public Set<Integer> create(Object... elements) {
+      // Would use Collections#checkedCollection, but I get:
+      // [ERROR] The method checkedCollection(Collection, Class<Integer>)
+      // is undefined for the type Collections
+      @SuppressWarnings("unchecked")  
+      Iterable<Integer> integers = (Iterable) Arrays.asList(elements);
+      
+      // I invert these before adding, so that the transformed set will have
+      // the expected elements themselves, not their image under the bijection
+      Set<Integer> invertedIntegers = Sets.newHashSet(Iterables.transform(integers,
+          integerBijection.inverse()));
+      return Sets.transform(invertedIntegers, integerBijection);
+    }
+
+    @Override public Integer[] createArray(int length) {
+      return new Integer[length];
+    }
+
+    @Override public SampleElements<Integer> samples() {
+      return new SampleElements<Integer>(-1, 0, 1, 2, 3);
+    }
+    
+    @Override public Iterable<Integer> order(List<Integer> insertionOrder) {
+      throw new AssertionError();
+    }
+  }
+}