为什么 Assert.Areequals (T objec1，Tobj2)与相同的字节数组失败

在下面的代码段中有两个相同的字节数组:

    /// <summary>
///A test for Bytes
///</summary>
[TestMethod()]
public void BytesTest() {
byte[] bytes = Encoding.UTF8.GetBytes(Properties.Resources.ExpectedPacketData);
TransferEventArgs target = new TransferEventArgs(bytes);


byte[] expected = Encoding.UTF8.GetBytes(Properties.Resources.ExpectedPacketValue);
byte[] actual;
actual = target.Bytes;


Assert.AreEqual(expected, actual);
}

这两个数组在字节上是完全相同的。在这种情况下，为什么断言？

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Because arrays don't override Equals.

You haven't said which test framework you're using, but basically it would be up to that framework to special-case arrays. You can always implement your own helper method to do that, of course. I've done that sometimes. For a quick and dirty hack, if you're using .NET 3.5 you can use the Enumerable.SequenceEqual extension method:

Assert.IsTrue(actual.SequenceEqual(expected));

A custom helper method could give you more details about how they differ, of course. You might find the methods in MoreLINQ.TestExtensions helpful, although they're fairly rough and ready too.

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最佳答案

Assert.Equals tests using the Equals method, which by default uses reference equality and, since they are different objects, they are not equal. You'll want to compare each byte in the array and verify that they are equal. One way to do this is convert them to something that implements ICollection and use CollectionAssert.AreEqual() instead.

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The method Assert.AreEqual under the hood will end up defaulting to Object.Equals() for non-null values. The default implementation of Object.Equals() is referential equality. The 2 arrays are identical value wise but difference reference wise and hence will not be considered equal.

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//Initialize your arrays here
byte[] array1 = new byte[0];
byte[] array2 = new byte[0];


Assert.AreEqual(System.Convert.ToBase64String(array1),
System.Convert.ToBase64String(array2));
小开 
byte[] a = new byte[] {x, y, z...};
byte[] b = new byte[] {x, y, z...};
assertArrayEquals(a , b );

will compare the stuff... It works for me..

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Created simple helper method:

private static void CompareArrays<T>(T[] expected, T[] actual)
{
Assert.AreEqual(expected == null, actual == null, "Expected {0}null value and {1}null found.", expected == null ? "" : "not", actual == null ? "" : "not");
if (expected == null || actual == null)
return;


Assert.AreEqual(expected.LongLength, actual.LongLength, "Expected Length is {0} actual: {1}", expected.LongLength, actual.LongLength);


for (int i = 0; i < expected.Length; i++)
{
Assert.AreEqual(expected[i], actual[i], "Values on index {0} are not equal. Expected {1} actual: {2}", i, expected[i], actual[i]);
}
}

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