Fix for incorrect error log being generated when a call to GetFiles should return empty as the filter removed all files but the folder did exist

Author: Jeavon

src/UmbracoFileSystemProviders.Azure.Tests/AzureBlobFileSystemTestsBase.cs

@@ -2,7 +2,6 @@
 // Copyright (c) James Jackson-South and contributors. All rights reserved.
 // Licensed under the Apache License, Version 2.0.
 // </copyright>
-
 namespace Our.Umbraco.FileSystemProviders.Azure.Tests
 {
     using System;
@@ -352,6 +351,23 @@ public void TestGetFilesFromRoot()
             Assert.IsTrue(expected.SequenceEqual(actual));
         }
 
+
+        /// <summary>
+        /// Asserts that a invalid path parameter passed to GetFiles returns null
+        /// </summary>
+        [Test]
+        public void TestGetFilesInvalidPath()
+        {
+            // Arrange
+            AzureBlobFileSystem provider = this.CreateAzureBlobFileSystem();
+
+            // Act
+            IEnumerable<string> actual = provider.GetFiles("/somethingmissing", "*.jpg");
+
+            // Assert
+            Assert.IsNull(actual);
+        }
+
         /// <summary>
         /// Asserts that the file system correctly returns a sequence of files from the root
         /// container in the correct format via a filtered request.

src/UmbracoFileSystemProviders.Azure/AzureFileSystem.cs

@@ -460,7 +460,16 @@ public IEnumerable<string> GetDirectories(string path)
         public IEnumerable<string> GetFiles(string path, string filter)
         {
             IEnumerable<IListBlobItem> blobs = this.cloudBlobContainer.ListBlobs(this.FixPath(path), true);
-            return blobs.OfType<CloudBlockBlob>().Select(cd =>
+
+            var blobList = blobs as IList<IListBlobItem> ?? blobs.ToList();
+
+            if (!blobList.Any())
+            {
+                this.LogHelper.Error<AzureFileSystem>("Blob not found", new DirectoryNotFoundException($"Blob not found at '{path}'"));
+                return null;
+            }
+
+            return blobList.OfType<CloudBlockBlob>().Select(cd =>
                 {
                     string url = cd.Uri.AbsoluteUri;
 
@@ -476,7 +485,6 @@ public IEnumerable<string> GetFiles(string path, string filter)
                         return url.Substring(this.rootContainerUrl.Length);
                     }
 
-                    this.LogHelper.Error<AzureFileSystem>("Directory not found", new DirectoryNotFoundException($"Directory not found at '{path}' with filter '{filter}'"));
                     return null;
                 }).Where(x => x != null);
         }