Add frag_depth qualifier execution test

src/webgpu/api/operation/rendering/depth.spec.ts

@@ -537,3 +537,100 @@ g.test('reverse_depth')
       },
     ]);
   });
+
+g.test('fragment_depth_qualifiers')
+  .desc(`Validates that less and greater qualifiers to @builtin(frag_depth) are accepted.`)
+  .params(u => u.combine('mode', ['less', 'greater']))
+  .fn(t => {
+    t.skipIfLanguageFeatureNotSupported('fragment_depth');
+
+    const { mode } = t.params;
+
+    const textureWidth = 1;
+    const textureHeight = 1;
+    const colorFormat = 'rgba8unorm';
+    const depthFormat = 'depth32float';
+
+    const val = mode === 'less' ? '0.4' : '0.6';
+    const pipeline = t.device.createRenderPipeline({
+      layout: 'auto',
+      vertex: {
+        module: t.device.createShaderModule({
+          code: `
+            @vertex
+            fn main() -> @builtin(position) vec4f {
+              return vec4f(0, 0, 0, 1);
+            }
+          `,
+        }),
+      },
+      fragment: {
+        module: t.device.createShaderModule({
+          code: `
+            requires fragment_depth;
+
+            struct Output {
+              @location(0) color: vec4f,
+              @builtin(frag_depth, ${mode}) depth: f32,
+            }
+
+            @fragment
+            fn main() -> Output {
+              return Output(vec4f(0, 1, 0, 1), ${val});
+            }
+          `,
+        }),
+        targets: [{ format: colorFormat }],
+      },
+      primitive: { topology: 'point-list' },
+      depthStencil: {
+        format: depthFormat,
+        depthWriteEnabled: true,
+        depthCompare: mode as GPUCompareFunction,
+      },
+    });
+
+    const colorTexture = t.createTextureTracked({
+      size: [textureWidth, textureHeight],
+      format: colorFormat,
+      usage: GPUTextureUsage.RENDER_ATTACHMENT | GPUTextureUsage.COPY_SRC,
+    });
+
+    const depthTexture = t.createTextureTracked({
+      size: [textureWidth, textureHeight],
+      format: depthFormat,
+      usage: GPUTextureUsage.RENDER_ATTACHMENT,
+    });
+
+    const encoder = t.device.createCommandEncoder();
+    const pass = encoder.beginRenderPass({
+      colorAttachments: [
+        {
+          view: colorTexture.createView(),
+          clearValue: { r: 1.0, g: 0.0, b: 0.0, a: 1.0 },
+          loadOp: 'clear',
+          storeOp: 'store',
+        },
+      ],
+      depthStencilAttachment: {
+        view: depthTexture.createView(),
+        depthClearValue: 0.5,
+        depthLoadOp: 'clear',
+        depthStoreOp: 'store',
+      },
+    });
+
+    pass.setPipeline(pipeline);
+    pass.draw(3);
+    pass.end();
+
+    t.device.queue.submit([encoder.finish()]);
+
+    const expectedColor = new Uint8Array([0, 255, 0, 255]);
+    ttu.expectSinglePixelComparisonsAreOkInTexture(t, { texture: colorTexture }, [
+      {
+        coord: { x: 0, y: 0 },
+        exp: expectedColor,
+      },
+    ]);
+  });