Give test image snapshots distinctive names.

Include the adapter name and driver name in the filenames generated to
store the `-actual.png` and `-difference.png` files holding
screenshots of test program output.

Previously, the filename only incorporated the backend, but since we
test the Vulkan backend on both Mac and Windows, one was overwriting
the other in the artifacts.

examples/common/src/framework.rs

@@ -625,7 +625,7 @@ pub fn test<E: Example>(mut params: FrameworkRefTest) {
 
             wgpu_test::image::compare_image_output(
                 env!("CARGO_MANIFEST_DIR").to_string() + "/../../" + params.image_path,
-                ctx.adapter_info.backend,
+                &ctx.adapter_info,
                 params.width,
                 params.height,
                 &bytes,

tests/src/image.rs

@@ -150,7 +150,7 @@ impl ComparisonType {
 
 pub fn compare_image_output(
     path: impl AsRef<Path> + AsRef<OsStr>,
-    backend: Backend,
+    adapter_info: &wgt::AdapterInfo,
     width: u32,
     height: u32,
     test_with_alpha: &[u8],
@@ -205,17 +205,18 @@ pub fn compare_image_output(
         }
 
         let file_stem = reference_path.file_stem().unwrap().to_string_lossy();
+        let renderer = format!(
+            "{}-{}-{}",
+            adapter_info.backend.to_str(),
+            sanitize_for_path(&adapter_info.name),
+            sanitize_for_path(&adapter_info.driver)
+        );
         // Determine the paths to write out the various intermediate files
         let actual_path = Path::new(&path).with_file_name(
-            OsString::from_str(&format!("{}-{}-actual.png", file_stem, backend.to_str(),)).unwrap(),
+            OsString::from_str(&format!("{}-{}-actual.png", file_stem, renderer)).unwrap(),
         );
         let difference_path = Path::new(&path).with_file_name(
-            OsString::from_str(&format!(
-                "{}-{}-difference.png",
-                file_stem,
-                backend.to_str(),
-            ))
-            .unwrap(),
+            OsString::from_str(&format!("{}-{}-difference.png", file_stem, renderer,)).unwrap(),
         );
 
         // Convert the error values to a false color reprensentation
@@ -246,10 +247,16 @@ pub fn compare_image_output(
 
     #[cfg(target_arch = "wasm32")]
     {
-        let _ = (path, backend, width, height, test_with_alpha, checks);
+        let _ = (path, adapter_info, width, height, test_with_alpha, checks);
     }
 }
 
+fn sanitize_for_path(s: &str) -> String {
+    s.chars()
+        .map(|ch| if ch.is_ascii_alphanumeric() { ch } else { '_' })
+        .collect()
+}
+
 fn copy_via_compute(
     device: &Device,
     encoder: &mut CommandEncoder,