test: fix flaky test in ClusterMachineConfigStatus unit tests

The test `TestSchematicChanges` was flaky, as it was doing the following:

1. Trigger one or more `factory.talos.dev` build image generations & talos node upgrades by modifying resources
2. Capture these upgrade calls
3. Assert the build image in these calls (to be one or more with, always the expected image)
4. Clear captured upgrade calls
5. Trigger one or more `ghcr.io` build image generations & talos node upgrades by modifying resources
6. Capture these upgrade calls
7. Assert the build image in these new calls (to be one or more with, always the expected image)

The problem was, between step 4 and 7, an old `factory.talos.dev` build image could sometimes still be captured due to the nature of controllers asynchronously reconciling resources.

Replace this logic by not clearing the upgrade requests at all, instead, simply ignoring the previous image's preceding captured requests in step 7.

Signed-off-by: Utku Ozdemir <utku.ozdemir@siderolabs.com>

internal/backend/runtime/omni/controllers/omni/cluster_machine_config_status_test.go

@@ -16,6 +16,7 @@ import (
 	"github.com/cosi-project/runtime/pkg/resource/rtestutils"
 	"github.com/cosi-project/runtime/pkg/safe"
 	"github.com/google/uuid"
+	"github.com/siderolabs/gen/xslices"
 	"github.com/siderolabs/go-retry/retry"
 	"github.com/siderolabs/talos/pkg/machinery/api/machine"
 	"github.com/siderolabs/talos/pkg/machinery/resources/runtime"
@@ -530,24 +531,23 @@ func (suite *ClusterMachineConfigStatusSuite) TestSchematicChanges() {
 		suite.Require().NoError(err)
 	}
 
+	expectedFactoryImage := "factory.talos.dev/installer/bbbb:v1.3.0"
+
 	suite.Require().NoError(retry.Constant(time.Second * 5).Retry(func() error {
 		requests := suite.machineService.getUpgradeRequests()
 		if len(requests) == 0 {
 			return retry.ExpectedErrorf("no upgrade requests received")
 		}
 
-		expectedImage := "factory.talos.dev/installer/bbbb:v1.3.0"
 		for i, r := range requests {
-			if r.Image != expectedImage {
-				return fmt.Errorf("%d request image is invalid: expected %q got %q", i, expectedImage, r.Image)
+			if r.Image != expectedFactoryImage {
+				return fmt.Errorf("%d request image is invalid: expected %q got %q", i, expectedFactoryImage, r.Image)
 			}
 		}
 
 		return nil
 	}))
 
-	suite.machineService.clearUpgradeRequests()
-
 	// check fallback to ghcr image if the schematic is invalid
 	for _, m := range machines {
 		machineStatus := omni.NewMachineStatus(resources.DefaultNamespace, m.Metadata().ID())
@@ -561,16 +561,29 @@ func (suite *ClusterMachineConfigStatusSuite) TestSchematicChanges() {
 		suite.Require().NoError(err)
 	}
 
+	trimLeadingImages := func(images []string, trim string) []string {
+		for i, image := range images {
+			if image != trim {
+				return images[i:]
+			}
+		}
+
+		return nil
+	}
+
 	suite.Require().NoError(retry.Constant(time.Second * 5).Retry(func() error {
 		requests := suite.machineService.getUpgradeRequests()
-		if len(requests) == 0 {
-			return retry.ExpectedErrorf("no upgrade requests received")
+		images := xslices.Map(requests, func(r *machine.UpgradeRequest) string { return r.Image })
+		trimmedImages := trimLeadingImages(images, expectedFactoryImage)
+
+		if len(trimmedImages) == 0 {
+			return retry.ExpectedErrorf("no new upgrade requests received")
 		}
 
 		expectedImage := "ghcr.io/siderolabs/installer:v1.3.0"
-		for i, r := range requests {
-			if r.Image != expectedImage {
-				return fmt.Errorf("%d request image is invalid: expected %q got %q", i, expectedImage, r.Image)
+		for i, image := range trimmedImages {
+			if image != expectedImage {
+				return fmt.Errorf("%d request image is invalid: expected %q got %q", i, expectedImage, image)
 			}
 		}
 
@@ -579,6 +592,8 @@ func (suite *ClusterMachineConfigStatusSuite) TestSchematicChanges() {
 }
 
 func (suite *ClusterMachineConfigStatusSuite) TestSecureBootInstallImage() {
+	suite.T().Cleanup(suite.machineService.clearUpgradeRequests)
+
 	suite.startRuntime()
 
 	suite.Require().NoError(suite.machineService.state.Create(suite.ctx, runtime.NewSecurityStateSpec(runtime.NamespaceName)))
@@ -658,8 +673,6 @@ func (suite *ClusterMachineConfigStatusSuite) TestSecureBootInstallImage() {
 
 		return nil
 	}))
-
-	suite.machineService.clearUpgradeRequests()
 }
 
 func (suite *ClusterMachineConfigStatusSuite) TestGenerationErrorPropagation() {