Add CEL validation tests for ObservabilityPolicy CRD

tests/cel/common.go

@@ -36,7 +36,7 @@ const (
 // ClientSettingsPolicy validation errors.
 const (
 	expectedTargetRefKindError       = `TargetRef Kind must be one of: Gateway, HTTPRoute, or GRPCRoute`
-	expectedTargetRefGroupError      = `TargetRef Group must be gateway.networking.k8s.io.`
+	expectedTargetRefGroupError      = `TargetRef Group must be gateway.networking.k8s.io`
 	expectedHeaderWithoutServerError = `header can only be specified if server is specified`
 )
 
@@ -47,6 +47,13 @@ const (
 	expectedMinReplicasLessThanOrEqualError = `minReplicas must be less than or equal to maxReplicas`
 )
 
+// ObservabilityPolicy validation errors.
+const (
+	expectedTargetRefMustBeHTTPRouteOrGrpcRouteError = `TargetRef Kind must be: HTTPRoute or GRPCRoute`
+	expectedTargetRefKindAndNameComboMustBeUnique    = `TargetRef Kind and Name combination must be unique`
+	expectedStrategyMustBeOfTypeRatio                = `ratio can only be specified if strategy is of type ratio`
+)
+
 // UpstreamSettingsPolicy validation errors.
 const (
 	expectedTargetRefKindServiceError = `TargetRefs Kind must be: Service`