Don't fail compatibility test when COS versions are not yet released.

COS can take a day or two to release a new version. While this is happening
versions can appear in gcloud projects, but not on the public site. In this
case, pass the tests so that we don't have failures while release is happening.

PiperOrigin-RevId: 713388040

test/gpu/cos_gpu_compatibility_test.go

@@ -53,6 +53,8 @@ func TestGPUDriversCompatibility(t *testing.T) {
 		t.Fatalf("Failed to unmarshal image JSON file: %v", err)
 	}
 
+	executedTests := 0
+
 	for _, image := range images {
 		name := image["name"].(string)
 		family := image["family"].(string)
@@ -95,7 +97,7 @@ func TestGPUDriversCompatibility(t *testing.T) {
 					default:
 						continue
 					}
-
+					executedTests++
 					if !supportedDrivers[driver.GetVersion()] {
 						t.Errorf("Unsupported driver patch: %q gpu: %q version: %q", driver.GetVersion(), info.GetGpuDevice().GetGpuType(), driver.GetLabel())
 						continue
@@ -106,6 +108,9 @@ func TestGPUDriversCompatibility(t *testing.T) {
 			}
 		})
 	}
+	if !t.Failed() && executedTests <= 0 {
+		t.Fatalf("No successful tests: check logs for details")
+	}
 }
 
 func imageNameToCosPatchVersion(imageName string, family string) (int, string, error) {
@@ -128,6 +133,12 @@ func listedDriverVersions(cosVersion string) ([]byte, error) {
 	// See: https://cloud.google.com/container-optimized-os/docs/release-notes
 	url := fmt.Sprintf("https://storage.googleapis.com/cos-tools/%s/lakitu/gpu_driver_versions.textproto", cosVersion)
 	resp, err := http.Get(url)
+	// When COS versions are newly released, they will often show up in projects but not the release
+	// page. In this case, we return an empty list of driver versions.
+	if resp.StatusCode == 404 {
+		resp.Body.Close()
+		return []byte("gpu_driver_version_info: []"), nil
+	}
 	if err != nil {
 		return nil, fmt.Errorf("failed to get driver versions for release %q: %w", cosVersion, err)
 	}