Fixed #1105 -- datatsets downloaded and expanded to the wrong folder.

Author: NiklasGustafsson

RELEASENOTES.md

@@ -7,6 +7,7 @@ Releases, starting with 9/2/2021, are listed with the most recent release at the
 __Bug Fixes__:
 
 Update to SkiaSharp 2.88.6 to avoid the libwebp vulnerability.<br/>
+#1105: Dataset files get written to the wrong directory<br/>
 
 ## NuGet Version 0.100.5
 

src/TorchVision/dsets/CIFAR.cs

@@ -92,7 +92,7 @@ protected void DownloadFile(string file, string target, string baseUrl)
                 if (!File.Exists(filePath)) {
                     lock (_httpClient) {
                         using var s = _httpClient.GetStreamAsync(netPath).Result;
-                        using var fs = new FileStream(file, FileMode.CreateNew);
+                        using var fs = new FileStream(filePath, FileMode.CreateNew);
                         s.CopyToAsync(fs).Wait();
                     }
                 }

test/TorchSharpTest/TestTorchVisionDatasets.cs

@@ -66,5 +66,17 @@ public void TestCelebaWithTransform()
                 }
             });
         }
+
+        [Fact]
+
+        public void TestMNISTDownload()
+        {
+            var data = torchvision.datasets.MNIST("TestMNISTDownload", true, true);
+
+            Assert.True(File.Exists(Path.Combine("TestMNISTDownload", "mnist", "train-images-idx3-ubyte.gz")));
+            Assert.True(File.Exists(Path.Combine("TestMNISTDownload", "mnist", "test_data", "train-images-idx3-ubyte")));
+            Assert.True(File.Exists(Path.Combine("TestMNISTDownload", "mnist", "t10k-images-idx3-ubyte.gz")));
+            Assert.True(File.Exists(Path.Combine("TestMNISTDownload", "mnist", "test_data", "t10k-images-idx3-ubyte")));
+        }
     }
 }