add comments and unit tests

src/Microsoft.ComponentDetection.Contracts/FileComponentDetectorWithCleanup.cs

@@ -82,6 +82,8 @@ protected async Task WithCleanupAsync(
             var (postSuccess, latestFiles, latestDirs) = this.TryGetFilesAndDirectories(fileParentDirectory, this.CleanupPatterns, DefaultCleanDepth);
             if (!postSuccess)
             {
+                // return early if we failed to get the latest files and directories, since we will not be able
+                // to determine what to clean up
                 return;
             }
 
@@ -159,8 +161,8 @@ private bool TryGetCleanupFileDirectory(ProcessRequest processRequest, out strin
         }
         catch (UnauthorizedAccessException e)
         {
-            // ignore files and directories that we don't have access to
-            this.Logger.LogDebug(e, "Failed to get files and directories for {Root}", root);
+            // log and return false if we are unauthorized to get files and directories
+            this.Logger.LogDebug(e, "Unauthorized to get files and directories for {Root}", root);
             return (false, new HashSet<string>(), new HashSet<string>());
         }
     }

test/Microsoft.ComponentDetection.Contracts.Tests/FileComponentDetectorWithCleanupTests.cs

@@ -111,8 +111,6 @@ public async Task WithCleanupAsync_CleansUpCreatedFile()
         var fileComponentDetector = new TestFileComponentDetector(["*.pyc"], this.loggerMock.Object, fileUtilityService, directoryUtilityService);
         var createdFilePath = Path.Combine(this.testDirectory, "todelete.pyc");
 
-        // Add files/dirs to the mock file system
-
         // Act
         await fileComponentDetector.TestCleanupAsync(
             (process, args, token) =>
@@ -198,6 +196,11 @@ await fileComponentDetector.TestCleanupAsync(
         fileUtilityService.Exists(this.existingFilePath).Should().BeTrue();
         directoryUtilityService.Exists(createdDirectory).Should().BeTrue();
         fileUtilityService.Exists(createdFilePath).Should().BeTrue();
+
+        // Assert we don't even try to read items
+        this.directoryUtilityServiceMock.Verify(
+            d => d.GetFilesAndDirectories(It.IsAny<string>(), It.IsAny<List<string>>(), It.IsAny<int>()),
+            Times.Never);
     }
 
     [TestMethod]
@@ -292,6 +295,40 @@ await fileComponentDetector.TestCleanupAsync(
         fileUtilityService.Exists(createdFilePath).Should().BeTrue();
     }
 
+    [TestMethod]
+    public async Task WithCleanupAsync_NoCleanup_WhenUnauthorized()
+    {
+        // Arrange
+        var fileUtilityService = this.fileUtilityServiceMock.Object;
+        var directoryUtilityService = this.directoryUtilityServiceMock.Object;
+        CancellationToken cancellationToken = default;
+        var detectorArgs = new Dictionary<string, string>();
+        var cleanupCreatedFiles = true;
+        var fileComponentDetector = new TestFileComponentDetector(["*.pyc"], this.loggerMock.Object, fileUtilityService, directoryUtilityService);
+        var createdFilePath = Path.Combine(this.testDirectory, "todelete.pyc");
+        this.directoryUtilityServiceMock
+            .Setup(d => d.GetFilesAndDirectories(It.IsAny<string>(), It.IsAny<List<string>>(), It.IsAny<int>()))
+            .Throws(new UnauthorizedAccessException("Unauthorized"));
+
+        // Act
+        await fileComponentDetector.TestCleanupAsync(
+            (process, args, token) =>
+            {
+                // creates a single file
+                this.fileSystemMockFiles.Add(createdFilePath);
+                return Task.CompletedTask;
+            },
+            this.processRequest,
+            detectorArgs,
+            cleanupCreatedFiles,
+            cancellationToken).ConfigureAwait(false);
+
+        // Assert
+        directoryUtilityService.Exists(this.testDirectory).Should().BeTrue();
+        fileUtilityService.Exists(this.existingFilePath).Should().BeTrue();
+        fileUtilityService.Exists(createdFilePath).Should().BeTrue();
+    }
+
     private bool IsPatternMatch(string path, string pattern)
     {
         return Regex.IsMatch(path, "^" + Regex.Escape(pattern).Replace("\\*", ".*") + "$");