Merge pull request #4671 from mithileshz/StreamsComparerEnhancement

Increment by 'Actual bytes read' rather than the buffer size in StreamsComparer.cs
nunit · Apr 9, 2024 · 612dd8c · 612dd8c
2 parents 4fa8396 + 6576b20
commit 612dd8c
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Showing 3 changed files with 28 additions and 3 deletions.
diff --git a/src/NUnitFramework/benchmarks/nunit.framework.benchmarks/StreamsComparerBenchmark.cs b/src/NUnitFramework/benchmarks/nunit.framework.benchmarks/StreamsComparerBenchmark.cs
@@ -153,7 +153,7 @@ public static EqualMethodResult Equal_Enhanced(Stream xStream, Stream yStream, o
 
                     if (MemoryExtensions.SequenceEqual<byte>(bufferExpected, bufferActual))
                     {
-                        readByte += BUFFER_SIZE;
+                        readByte += readActual;
                         continue;
                     }
 

diff --git a/src/NUnitFramework/framework/Constraints/Comparers/StreamsComparer.cs b/src/NUnitFramework/framework/Constraints/Comparers/StreamsComparer.cs
@@ -70,7 +70,7 @@ public static EqualMethodResult Equal(object x, object y, ref Tolerance toleranc
 
                     if (MemoryExtensions.SequenceEqual<byte>(bufferExpected, bufferActual))
                     {
-                        readByte += BUFFER_SIZE;
+                        readByte += readActual;
                         continue;
                     }
 
@@ -88,7 +88,6 @@ public static EqualMethodResult Equal(object x, object y, ref Tolerance toleranc
                             return EqualMethodResult.ComparedNotEqual;
                         }
                     }
-                    readByte += BUFFER_SIZE;
                 }
             }
             finally

diff --git a/src/NUnitFramework/tests/Constraints/EqualConstraintTests.cs b/src/NUnitFramework/tests/Constraints/EqualConstraintTests.cs
@@ -243,6 +243,20 @@ public void UnSeekableLargeActualStreamUnequal()
                 Assert.That(entryStream, Is.Not.EqualTo(expectedStream));
             }
 
+            [Test]
+            public void ShortReadingMemoryStream_AssertErrorMessageFailurePointIsCorrect()
+            {
+                var unequalStream = HelloString.Remove(HelloString.Length - 1, 1) + ".";
+
+                using var expectedStream = new ShortReadingMemoryStream(Encoding.UTF8.GetBytes(HelloString));
+
+                using var entryStream = new ShortReadingMemoryStream(Encoding.UTF8.GetBytes(unequalStream));
+
+                var ex = Assert.Throws<AssertionException>(() => Assert.That(entryStream, Is.EqualTo(expectedStream)));
+
+                Assert.That(ex?.Message, Does.Contain("Stream lengths are both 9. Streams differ at offset 8."));
+            }
+
             [Test]
             public void SeekableEmptyStreamEqual()
             {
@@ -269,6 +283,18 @@ private static ZipArchive CreateZipArchive(string content)
 
                 return new ZipArchive(archiveContents, ZipArchiveMode.Read, leaveOpen: false);
             }
+
+            private class ShortReadingMemoryStream : MemoryStream
+            {
+                public ShortReadingMemoryStream(byte[] bytes) : base(bytes)
+                {
+                }
+
+                public override int Read(byte[] buffer, int offset, int count)
+                {
+                    return base.Read(buffer, offset, 2);
+                }
+            }
         }
 
         #endregion