fix test flake caused by not waiting for CRD schema update

staging/src/k8s.io/apiextensions-apiserver/test/integration/ratcheting_test.go

@@ -220,23 +220,12 @@ func (u updateMyCRDV1Beta1Schema) Do(ctx *ratchetingTestContext) error {
 		}
 
 		uuidString := string(uuid.NewUUID())
-		// UUID string is just hex separated by dashes, which is safe to
-		// throw into regex like this
-		pattern := "^" + uuidString + "$"
 		sentinelName := "__ratcheting_sentinel_field__"
 		sch.Properties[sentinelName] = apiextensionsv1.JSONSchemaProps{
-			Type:    "string",
-			Pattern: pattern,
-
-			// Put MaxLength condition inside AllOf since the string_validator
-			// in kube-openapi short circuits upon seeing MaxLength, and we
-			// want both pattern and MaxLength errors
-			AllOf: []apiextensionsv1.JSONSchemaProps{
-				{
-					MinLength: ptr((int64(1))), // 1 MinLength to prevent empty value from ever being admitted
-					MaxLength: ptr((int64(0))), // 0 MaxLength to prevent non-empty value from ever being admitted
-				},
-			},
+			Type: "string",
+			Enum: []apiextensionsv1.JSON{{
+				Raw: []byte(`"` + uuidString + `"`),
+			}},
 		}
 
 		for _, v := range myCRD.Spec.Versions {
@@ -254,7 +243,7 @@ func (u updateMyCRDV1Beta1Schema) Do(ctx *ratchetingTestContext) error {
 		}
 
 		// Keep trying to create an invalid instance of the CRD until we
-		// get an error containing the ResourceVersion we are looking for
+		// get an error containing the message we are looking for
 		//
 		counter := 0
 		return wait.PollUntilContextCancel(context.TODO(), 100*time.Millisecond, true, func(_ context.Context) (done bool, err error) {
@@ -263,8 +252,7 @@ func (u updateMyCRDV1Beta1Schema) Do(ctx *ratchetingTestContext) error {
 				gvr:  myCRDV1Beta1,
 				name: "sentinel-resource",
 				patch: map[string]interface{}{
-					// Just keep using different values
-					sentinelName: fmt.Sprintf("invalid %v %v", uuidString, counter),
+					sentinelName: fmt.Sprintf("invalid-%d", counter),
 				}}.Do(ctx)
 
 			if err == nil {