Fixed failing tests

src/ImageSharp/Formats/Jpeg/Components/Encoder/HuffmanScanEncoder.cs

@@ -303,8 +303,6 @@ namespace SixLabors.ImageSharp.Formats.Jpeg.Components.Encoder
         {
             this.huffmanTables = HuffmanLut.TheHuffmanLut;
 
-            var unzig = ZigZag.CreateUnzigTable();
-
             // ReSharper disable once InconsistentNaming
             int prevDCR = 0, prevDCG = 0, prevDCB = 0;
 
@@ -327,26 +325,28 @@ namespace SixLabors.ImageSharp.Formats.Jpeg.Components.Encoder
                         QuantIndex.Luminance,
                         prevDCR,
                         ref pixelConverter.R,
-                        ref luminanceQuantTable,
+                        ref luminanceQuantTable);
-                        ref unzig);
 
                     prevDCG = this.WriteBlock(
                         QuantIndex.Luminance,
                         prevDCG,
                         ref pixelConverter.G,
-                        ref luminanceQuantTable,
+                        ref luminanceQuantTable);
-                        ref unzig);
 
                     prevDCB = this.WriteBlock(
                         QuantIndex.Luminance,
                         prevDCB,
                         ref pixelConverter.B,
-                        ref luminanceQuantTable,
+                        ref luminanceQuantTable);
-                        ref unzig);
+
+                    if (this.IsFlushNeeded)
+                    {
+                        this.FlushToStream();
+                    }
                 }
             }
 
-            this.FlushInternalBuffer();
+            this.FlushRemainingBytes();
         }
 
         /// <summary>

tests/ImageSharp.Tests/Formats/Jpg/Block8x8Tests.cs

@@ -248,24 +248,26 @@ namespace SixLabors.ImageSharp.Tests.Formats.Jpg
                     short fillValue = (short)rng.Next(-2000, 2000);
 
                     // first filled chunk
-                    int lastIndex1 = rng.Next(1, Block8x8F.Size / 2);
+                    int firstChunkStart = rng.Next(0, Block8x8.Size / 2);
-                    for (int dataIndex = 0; dataIndex <= lastIndex1; dataIndex++)
+                    int firstChunkEnd = rng.Next(firstChunkStart, Block8x8.Size / 2);
+                    for (int dataIdx = firstChunkStart; dataIdx <= firstChunkEnd; dataIdx++)
                     {
-                        data[dataIndex] = fillValue;
+                        data[dataIdx] = fillValue;
                     }
 
                     // second filled chunk, there might be a spot with zero(s) between first and second chunk
-                    int lastIndex2 = rng.Next(lastIndex1 + 1, Block8x8F.Size);
+                    int secondChunkStart = rng.Next(firstChunkEnd, Block8x8.Size);
-                    for (int dataIndex = 0; dataIndex <= lastIndex2; dataIndex++)
+                    int secondChunkEnd = rng.Next(secondChunkStart, Block8x8.Size);
+                    for (int dataIdx = secondChunkStart; dataIdx <= secondChunkEnd; dataIdx++)
                     {
-                        data[dataIndex] = fillValue;
+                        data[dataIdx] = fillValue;
                     }
 
-                    int expected = lastIndex2;
+                    int expected = secondChunkEnd;
 
                     int actual = data.GetLastNonZeroIndex();
 
-                    Assert.Equal(expected, actual);
+                    Assert.True(expected == actual, $"Expected: {expected}\nActual: {actual}\nInput matrix: {data}");
                 }
             }