Add minor ray tracing tests (#6651)

CHANGELOG.md

@@ -152,6 +152,10 @@ By @ErichDonGubler in [#6456](https://github.com/gfx-rs/wgpu/pull/6456), [#6148]
 - Fix crash when a texture argument is missing. By @aedm in [#6486](https://github.com/gfx-rs/wgpu/pull/6486)
 - Emit an error in constant evaluation, rather than crash, in certain cases where `vecN` constructors have less than N arguments. By @ErichDonGubler in [#6508](https://github.com/gfx-rs/wgpu/pull/6508).
 
+### Testing
+
+- Tests the early returns in the acceleration structure build calls with empty calls. By @Vecvec in [#6651](https://github.com/gfx-rs/wgpu/pull/6651).
+
 ## 23.0.1 (2024-11-25)
 
 This release includes patches for `wgpu`, `wgpu-core` and `wgpu-hal`. All other crates remain at [23.0.0](https://github.com/gfx-rs/wgpu/releases/tag/v23.0.0).

tests/tests/ray_tracing/as_build.rs

@@ -1,4 +1,4 @@
-use std::mem;
+use std::{iter, mem};
 
 use wgpu::{
     util::{BufferInitDescriptor, DeviceExt},
@@ -283,3 +283,36 @@ fn out_of_order_as_build_use(ctx: TestingContext) {
         None,
     );
 }
+
+#[gpu_test]
+static EMPTY_BUILD: GpuTestConfiguration = GpuTestConfiguration::new()
+    .parameters(
+        TestParameters::default()
+            .test_features_limits()
+            .features(wgpu::Features::EXPERIMENTAL_RAY_TRACING_ACCELERATION_STRUCTURE),
+    )
+    .run_sync(empty_build);
+fn empty_build(ctx: TestingContext) {
+    let mut encoder_safe = ctx
+        .device
+        .create_command_encoder(&CommandEncoderDescriptor {
+            label: Some("BLAS 1"),
+        });
+
+    encoder_safe.build_acceleration_structures(iter::empty(), iter::empty());
+
+    let mut encoder_unsafe = ctx
+        .device
+        .create_command_encoder(&CommandEncoderDescriptor {
+            label: Some("BLAS 1"),
+        });
+
+    // # SAFETY:
+    // we don't actually do anything so all the requirements are satisfied
+    unsafe {
+        encoder_unsafe.build_acceleration_structures_unsafe_tlas(iter::empty(), iter::empty());
+    }
+
+    ctx.queue
+        .submit([encoder_safe.finish(), encoder_unsafe.finish()]);
+}