Nuclex.Support/Tests/Collections/TransformingReadOnlyCollectionTest.cs

#region Apache License 2.0
/*
Nuclex .NET Framework
Copyright (C) 2002-2024 Markus Ewald / Nuclex Development Labs

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.
*/
#endregion // Apache License 2.0

#if !NO_NMOCK

using System;
using System.Collections;
using System.Collections.Generic;

#if UNITTEST

using NUnit.Framework;
using NMock;

namespace Nuclex.Support.Collections {

  /// <summary>Unit Test for the transforming read only collection wrapper</summary>
  [TestFixture]
  internal class TransformingReadOnlyCollectionTest {

    #region class StringTransformer

    /// <summary>Test implementation of a transforming collection</summary>
    private class StringTransformer : TransformingReadOnlyCollection<int, string> {

      /// <summary>Initializes a new int-to-string transforming collection</summary>
      /// <param name="items">Items the transforming collection will contain</param>
      public StringTransformer(IList<int> items) : base(items) { }

      /// <summary>Transforms an item into the exposed type</summary>
      /// <param name="item">Item to be transformed</param>
      /// <returns>The transformed item</returns>
      /// <remarks>
      ///   This method is used to transform an item in the wrapped collection into
      ///   the exposed item type whenever the user accesses an item. Expect it to
      ///   be called frequently, because the TransformingReadOnlyCollection does
      ///   not cache or otherwise store the transformed items.
      /// </remarks>
      protected override string Transform(int item) {
        if(item == 42) {
          return null;
        }

        return item.ToString();
      }

    }

    #endregion // class StringTransformer

    /// <summary>
    ///   Verifies that the copy constructor of the transforming read only collection works
    /// </summary>
    [Test]
    public void TestCopyConstructor() {
      int[] integers = new int[] { 12, 34, 56, 78 };
      StringTransformer testCollection = new StringTransformer(integers);

      string[] strings = new string[] { "12", "34", "56", "78" };
      CollectionAssert.AreEqual(strings, testCollection);
    }

    /// <summary>Verifies that the IsReadOnly property returns true</summary>
    [Test]
    public void TestIsReadOnly() {
      StringTransformer testCollection = new StringTransformer(new int[0]);

      Assert.IsTrue(testCollection.IsReadOnly);
    }

    /// <summary>
    ///   Verifies that the CopyTo() method of the transforming read only collection works
    /// </summary>
    [Test]
    public void TestCopyToArray() {
      int[] inputIntegers = new int[] { 12, 34, 56, 78 };
      StringTransformer testCollection = new StringTransformer(inputIntegers);

      string[] inputStrings = new string[] { "12", "34", "56", "78" };
      string[] outputStrings = new string[testCollection.Count];
      testCollection.CopyTo(outputStrings, 0);

      CollectionAssert.AreEqual(inputStrings, outputStrings);
    }

    /// <summary>
    ///   Verifies that the CopyTo() method of the transforming read only collection throws
    ///   an exception if the target array is too small to hold the collection's contents
    /// </summary>
    [Test]
    public void TestThrowOnCopyToTooSmallArray() {
      int[] inputIntegers = new int[] { 12, 34, 56, 78 };
      StringTransformer testCollection = new StringTransformer(inputIntegers);

      string[] outputStrings = new string[testCollection.Count - 1];
      Assert.Throws<ArgumentException>(
        delegate() { testCollection.CopyTo(outputStrings, 0); }
      );
    }

    /// <summary>
    ///   Checks whether the Contains() method of the transforming read only collection
    ///   is able to determine if the collection contains an item
    /// </summary>
    [Test]
    public void TestContains() {
      int[] integers = new int[] { 1234, 6789 };
      StringTransformer testCollection = new StringTransformer(integers);

      Assert.IsTrue(testCollection.Contains("1234"));
      Assert.IsFalse(testCollection.Contains("4321"));
    }

    /// <summary>
    ///   Checks whether the IndexOf() method of the transforming read only collection
    ///   is able to determine if the index of an item in the collection
    /// </summary>
    [Test]
    public void TestIndexOf() {
      int[] integers = new int[] { 12, 34, 67, 89 };
      StringTransformer testCollection = new StringTransformer(integers);

      Assert.AreEqual(0, testCollection.IndexOf("12"));
      Assert.AreEqual(1, testCollection.IndexOf("34"));
      Assert.AreEqual(2, testCollection.IndexOf("67"));
      Assert.AreEqual(3, testCollection.IndexOf("89"));
    }

    /// <summary>
    ///   Checks whether the IndexOf() method of the transforming read only collection
    ///   can cope with queries for 'null' when no 'null' item is contained on it
    /// </summary>
    [Test]
    public void TestIndexOfWithNullItemNotContained() {
      int[] integers = new int[] { 12, 34, 67, 89 };
      StringTransformer testCollection = new StringTransformer(integers);

      Assert.AreEqual(-1, testCollection.IndexOf(null));
    }

    /// <summary>
    ///   Checks whether the IndexOf() method of the transforming read only collection
    ///   can cope with queries for 'null' when a 'null' item is contained on it
    /// </summary>
    [Test]
    public void TestIndexOfWithNullItemContained() {
      int[] integers = new int[] { 12, 34, 67, 89, 42 };
      StringTransformer testCollection = new StringTransformer(integers);

      Assert.AreEqual(4, testCollection.IndexOf(null));
    }

    /// <summary>
    ///   Verifies that the Enumerator of the transforming read only collection correctly
    ///   implements the Reset() method
    /// </summary>
    [Test]
    public void TestEnumeratorReset() {
      int[] integers = new int[] { 1234, 6789 };
      StringTransformer testCollection = new StringTransformer(integers);

      IEnumerator<string> stringEnumerator = testCollection.GetEnumerator();
      Assert.IsTrue(stringEnumerator.MoveNext());
      Assert.IsTrue(stringEnumerator.MoveNext());
      Assert.IsFalse(stringEnumerator.MoveNext());

      stringEnumerator.Reset();

      Assert.IsTrue(stringEnumerator.MoveNext());
      Assert.IsTrue(stringEnumerator.MoveNext());
      Assert.IsFalse(stringEnumerator.MoveNext());
    }

    /// <summary>
    ///   Checks whether the indexer method of the transforming read only collection
    ///   is able to retrieve items from the collection
    /// </summary>
    [Test]
    public void TestRetrieveByIndexer() {
      int[] integers = new int[] { 12, 34, 67, 89 };
      StringTransformer testCollection = new StringTransformer(integers);

      Assert.AreEqual("12", testCollection[0]);
      Assert.AreEqual("34", testCollection[1]);
      Assert.AreEqual("67", testCollection[2]);
      Assert.AreEqual("89", testCollection[3]);
    }

    /// <summary>
    ///   Checks whether the transforming read only collection will throw an exception
    ///   if its Insert() method is called via the generic IList&lt;&gt; interface
    /// </summary>
    [Test]
    public void TestThrowOnInsertViaGenericIList() {
      StringTransformer testCollection = new StringTransformer(new int[0]);
      Assert.Throws<NotSupportedException>(
        delegate() { (testCollection as IList<string>).Insert(0, "12345"); }
      );
    }

    /// <summary>
    ///   Checks whether the transforming read only collection will throw an exception
    ///   if its RemoveAt() method is called via the generic IList&lt;&gt; interface
    /// </summary>
    [Test]
    public void TestThrowOnRemoveViaGenericIList() {
      StringTransformer testCollection = new StringTransformer(new int[1]);
      Assert.Throws<NotSupportedException>(
        delegate() { (testCollection as IList<string>).RemoveAt(0); }
      );
    }

    /// <summary>
    ///   Checks whether the indexer method of the transforming read only collection will
    ///   throw an exception if it is attempted to be used for replacing an item
    /// </summary>
    [Test]
    public void TestRetrieveByIndexerViaGenericIList() {
      int[] integers = new int[] { 12, 34, 67, 89 };
      StringTransformer testCollection = new StringTransformer(integers);

      Assert.AreEqual("12", (testCollection as IList<string>)[0]);
      Assert.AreEqual("34", (testCollection as IList<string>)[1]);
      Assert.AreEqual("67", (testCollection as IList<string>)[2]);
      Assert.AreEqual("89", (testCollection as IList<string>)[3]);
    }

    /// <summary>
    ///   Checks whether the indexer method of the transforming read only collection
    ///   will throw an exception if it is attempted to be used for replacing an item
    /// </summary>
    [Test]
    public void TestThrowOnReplaceByIndexerViaGenericIList() {
      StringTransformer testCollection = new StringTransformer(new int[1]);

      Assert.Throws<NotSupportedException>(
        delegate() { (testCollection as IList<string>)[0] = "12345"; }
      );
    }

    /// <summary>
    ///   Checks whether the transforming read only collection will throw an exception
    ///   if its Add() method is called via the generic ICollection&lt;&gt; interface
    /// </summary>
    [Test]
    public void TestThrowOnAddViaGenericICollection() {
      StringTransformer testCollection = new StringTransformer(new int[0]);
      Assert.Throws<NotSupportedException>(
        delegate() { (testCollection as ICollection<string>).Add("12345"); }
      );
    }

    /// <summary>
    ///   Checks whether the transforming read only collection will throw an exception
    ///   if its Clear() method is called via the generic ICollection&lt;&gt; interface
    /// </summary>
    [Test]
    public void TestThrowOnClearViaGenericICollection() {
      StringTransformer testCollection = new StringTransformer(new int[1]);
      Assert.Throws<NotSupportedException>(
        delegate() { (testCollection as ICollection<string>).Clear(); }
      );
    }

    /// <summary>
    ///   Checks whether the transforming read only collection will throw an exception
    ///   if its Remove() method is called via the generic ICollection&lt;&gt; interface
    /// </summary>
    [Test]
    public void TestThrowOnRemoveViaGenericICollection() {
      int[] integers = new int[] { 12, 34, 67, 89 };
      StringTransformer testCollection = new StringTransformer(integers);

      Assert.Throws<NotSupportedException>(
        delegate() { (testCollection as ICollection<string>).Remove("89"); }
      );
    }

    /// <summary>
    ///   Tests whether the typesafe enumerator of the read only collection is working
    /// </summary>
    [Test]
    public void TestTypesafeEnumerator() {
      int[] inputIntegers = new int[] { 12, 34, 56, 78 };
      StringTransformer testCollection = new StringTransformer(inputIntegers);

      List<string> outputStrings = new List<string>();
      foreach(string value in testCollection) {
        outputStrings.Add(value);
      }

      string[] inputStrings = new string[] { "12", "34", "56", "78" };
      CollectionAssert.AreEqual(inputStrings, outputStrings);
    }

    /// <summary>
    ///   Checks whether the transforming read only collection will throw an exception
    ///   if its Clear() method is called via the IList interface
    /// </summary>
    [Test]
    public void TestThrowOnClearViaIList() {
      StringTransformer testCollection = new StringTransformer(new int[1]);
      Assert.Throws<NotSupportedException>(
        delegate() { (testCollection as IList).Clear(); }
      );
    }

    /// <summary>
    ///   Checks whether the transforming read only collection will throw an exception
    ///   if its Add() method is called via the IList interface
    /// </summary>
    [Test]
    public void TestThrowOnAddViaIList() {
      StringTransformer testCollection = new StringTransformer(new int[0]);
      Assert.Throws<NotSupportedException>(
        delegate() { (testCollection as IList).Add("12345"); }
      );
    }

    /// <summary>
    ///   Checks whether the Contains() method of the transforming read only collection
    ///   is able to determine if the collection contains an item
    /// </summary>
    [Test]
    public void TestContainsViaIList() {
      int[] integers = new int[] { 1234, 6789 };
      StringTransformer testCollection = new StringTransformer(integers);

      Assert.IsTrue((testCollection as IList).Contains("1234"));
      Assert.IsFalse((testCollection as IList).Contains("4321"));
    }

    /// <summary>
    ///   Checks whether the IndexOf() method of the transforming read only collection
    ///   is able to determine if the index of an item in the collection
    /// </summary>
    [Test]
    public void TestIndexOfViaIList() {
      int[] integers = new int[] { 12, 34, 67, 89 };
      StringTransformer testCollection = new StringTransformer(integers);

      Assert.AreEqual(0, (testCollection as IList).IndexOf("12"));
      Assert.AreEqual(1, (testCollection as IList).IndexOf("34"));
      Assert.AreEqual(2, (testCollection as IList).IndexOf("67"));
      Assert.AreEqual(3, (testCollection as IList).IndexOf("89"));
    }

    /// <summary>
    ///   Checks whether the transforming read only collection will throw an exception
    ///   if its Insert() method is called via the IList interface
    /// </summary>
    [Test]
    public void TestThrowOnInsertViaIList() {
      StringTransformer testCollection = new StringTransformer(new int[0]);
      Assert.Throws<NotSupportedException>(
        delegate() { (testCollection as IList).Insert(0, "12345"); }
      );
    }

    /// <summary>
    ///   Checks whether the IsFixedSize property of the transforming read only collection
    ///   returns the expected result for a transforming read only collection based on
    ///   a fixed array
    /// </summary>
    [Test]
    public void TestIsFixedSizeViaIList() {
      int[] integers = new int[] { 12, 34, 67, 89 };
      StringTransformer testCollection = new StringTransformer(integers);

      Assert.IsTrue((testCollection as IList).IsFixedSize);
    }

    /// <summary>
    ///   Checks whether the transforming read only collection will throw an exception
    ///   if its Remove() method is called via the IList interface
    /// </summary>
    [Test]
    public void TestThrowOnRemoveViaIList() {
      int[] integers = new int[] { 1234, 6789 };
      StringTransformer testCollection = new StringTransformer(integers);

      Assert.Throws<NotSupportedException>(
        delegate() { (testCollection as IList).Remove("6789"); }
      );
    }

    /// <summary>
    ///   Checks whether the transforming read only collection will throw an exception
    ///   if its Remove() method is called via the IList interface
    /// </summary>
    [Test]
    public void TestThrowOnRemoveAtViaIList() {
      StringTransformer testCollection = new StringTransformer(new int[1]);

      Assert.Throws<NotSupportedException>(
        delegate() { (testCollection as IList).RemoveAt(0); }
      );
    }

    /// <summary>
    ///   Checks whether the indexer method of the transforming read only collection
    ///   will throw an exception if it is attempted to be used for replacing an item
    /// </summary>
    [Test]
    public void TestRetrieveByIndexerViaIList() {
      int[] integers = new int[] { 12, 34, 67, 89 };
      StringTransformer testCollection = new StringTransformer(integers);

      Assert.AreEqual("12", (testCollection as IList)[0]);
      Assert.AreEqual("34", (testCollection as IList)[1]);
      Assert.AreEqual("67", (testCollection as IList)[2]);
      Assert.AreEqual("89", (testCollection as IList)[3]);
    }

    /// <summary>
    ///   Checks whether the indexer method of the transforming read only collection
    ///   will throw an exception if it is attempted to be used for replacing an item
    /// </summary>
    [Test]
    public void TestThrowOnReplaceByIndexerViaIList() {
      StringTransformer testCollection = new StringTransformer(new int[1]);

      Assert.Throws<NotSupportedException>(
        delegate() { (testCollection as IList)[0] = "12345"; }
      );
    }

    /// <summary>
    ///   Verifies that the CopyTo() method of the transforming read only collection
    ///   works if invoked via the ICollection interface
    /// </summary>
    [Test]
    public void TestCopyToArrayViaICollection() {
      int[] inputIntegers = new int[] { 12, 34, 56, 78 };
      StringTransformer testCollection = new StringTransformer(inputIntegers);

      string[] outputStrings = new string[testCollection.Count];
      (testCollection as ICollection).CopyTo(outputStrings, 0);

      string[] inputStrings = new string[] { "12", "34", "56", "78" };
      CollectionAssert.AreEqual(inputStrings, outputStrings);
    }

    /// <summary>
    ///   Verifies that the IsSynchronized property and the SyncRoot property are working
    /// </summary>
    [Test]
    public void TestSynchronization() {
      StringTransformer testCollection = new StringTransformer(new int[0]);

      if(!(testCollection as ICollection).IsSynchronized) {
        lock((testCollection as ICollection).SyncRoot) {
          Assert.AreEqual(0, testCollection.Count);
        }
      }
    }

    /// <summary>
    ///   Verifies that the IsSynchronized property and the SyncRoot property are working
    ///   on transforming read only collections based on IList&lt;&gt;s that do not
    ///   implement the ICollection interface
    /// </summary>
    [Test]
    public void TestSynchronizationOfIListWithoutICollection() {
      MockFactory mockery = new MockFactory();
      Mock<IList<int>> mockedIList = mockery.CreateMock<IList<int>>();
      StringTransformer testCollection = new StringTransformer(mockedIList.MockObject);

      if(!(testCollection as ICollection).IsSynchronized) {
        lock((testCollection as ICollection).SyncRoot) {
          mockedIList.Expects.One.GetProperty(p => p.Count).WillReturn(12345);
          int count = testCollection.Count;
          Assert.AreEqual(12345, count); // ;-)
        }
      }
    }

  }

} // namespace Nuclex.Support.Collections

#endif // UNITTEST

#endif // !NO_NMOCK