Fix ItemWithPath to throw on null/empty/whitespace path

Co-authored-by: lramosvea <77297467+lramosvea@users.noreply.github.com>

Author: Copilot

src/Microsoft.Graph/Extensions/DriveItemRequestBuilderExtensions.cs

@@ -44,12 +44,14 @@ public static class DriveItemRequestBuilderExtensions
     /// </summary>
     public static CustomDriveItemItemRequestBuilder ItemWithPath(this Microsoft.Graph.Drives.Item.Root.RootRequestBuilder rootRequestBuilder, string path)
     {
-        if (!string.IsNullOrEmpty(path))
+        if (path is null)
+            throw new ArgumentNullException(nameof(path));
+        if (string.IsNullOrWhiteSpace(path))
+            throw new ArgumentException("path cannot be empty or whitespace.", nameof(path));
+
+        if (!path.StartsWith("/"))
         {
-            if (!path.StartsWith("/"))
-            {
-                path = string.Format("/{0}", path);
-            }
+            path = string.Format("/{0}", path);
         }
 
         var requestInformation = rootRequestBuilder.ToGetRequestInformation();
@@ -67,12 +69,14 @@ public static CustomDriveItemItemRequestBuilder ItemWithPath(this Microsoft.Grap
     /// </summary>
     public static CustomDriveItemItemRequestBuilder ItemWithPath(this Microsoft.Graph.Drives.Item.Items.Item.DriveItemItemRequestBuilder rootRequestBuilder, string path)
     {
-        if (!string.IsNullOrEmpty(path))
+        if (path is null)
+            throw new ArgumentNullException(nameof(path));
+        if (string.IsNullOrWhiteSpace(path))
+            throw new ArgumentException("path cannot be empty or whitespace.", nameof(path));
+
+        if (!path.StartsWith("/"))
         {
-            if (!path.StartsWith("/"))
-            {
-                path = string.Format("/{0}", path);
-            }
+            path = string.Format("/{0}", path);
         }
 
         var requestInformation = rootRequestBuilder.ToGetRequestInformation();

tests/Microsoft.Graph.DotnetCore.Test/Requests/Extensions/DriveItemRequestBuilderExtensionsTests.cs

@@ -141,5 +141,37 @@ public void ItemByPath_BuildRequestWithNestedPathSlashAndMoreThanOneParameter()
             Assert.NotNull(itemRequestInformation);
             Assert.Equal(expectedRequestUri, itemRequestInformation.URI);
         }
+        [Fact]
+        public void ItemByPath_ThrowsArgumentNullException_WhenPathIsNull_Root()
+        {
+            var graphServiceClient = new GraphServiceClient(new MockAuthenticationProvider().Object);
+            Assert.Throws<ArgumentNullException>(() => graphServiceClient.Drives["driveId"].Root.ItemWithPath(null));
+        }
+
+        [Theory]
+        [InlineData("")]
+        [InlineData("   ")]
+        public void ItemByPath_ThrowsArgumentException_WhenPathIsEmptyOrWhitespace_Root(string path)
+        {
+            var graphServiceClient = new GraphServiceClient(new MockAuthenticationProvider().Object);
+            Assert.Throws<ArgumentException>(() => graphServiceClient.Drives["driveId"].Root.ItemWithPath(path));
+        }
+
+        [Fact]
+        public void ItemByPath_ThrowsArgumentNullException_WhenPathIsNull_DriveItem()
+        {
+            var graphServiceClient = new GraphServiceClient(new MockAuthenticationProvider().Object);
+            Assert.Throws<ArgumentNullException>(() => graphServiceClient.Drives["driveId"].Items["itemId"].ItemWithPath(null));
+        }
+
+        [Theory]
+        [InlineData("")]
+        [InlineData("   ")]
+        public void ItemByPath_ThrowsArgumentException_WhenPathIsEmptyOrWhitespace_DriveItem(string path)
+        {
+            var graphServiceClient = new GraphServiceClient(new MockAuthenticationProvider().Object);
+            Assert.Throws<ArgumentException>(() => graphServiceClient.Drives["driveId"].Items["itemId"].ItemWithPath(path));
+        }
+
     }
 }