create mlmodel_service in testutils/inject (#2205)

testutils/inject/mlmodel_service.go

@@ -0,0 +1,30 @@
+package inject
+
+import (
+	"context"
+
+	"go.viam.com/rdk/services/mlmodel"
+)
+
+// MLModelService represents a fake instance of a mlmodel service.
+type MLModelService struct {
+	mlmodel.Service
+	InferFunc    func(ctx context.Context, input map[string]interface{}) (map[string]interface{}, error)
+	MetadataFunc func(ctx context.Context) (mlmodel.MLMetadata, error)
+}
+
+// Infer calls the injected InferFunc or the real version.
+func (mlmodelSvc *MLModelService) Infer(ctx context.Context, input map[string]interface{}) (map[string]interface{}, error) {
+	if mlmodelSvc.InferFunc == nil {
+		return mlmodelSvc.Service.Infer(ctx, input)
+	}
+	return mlmodelSvc.InferFunc(ctx, input)
+}
+
+// Metadata calls the injected MetadataFunc or the real version.
+func (mlmodelSvc *MLModelService) Metadata(ctx context.Context) (mlmodel.MLMetadata, error) {
+	if mlmodelSvc.MetadataFunc == nil {
+		return mlmodelSvc.Service.Metadata(ctx)
+	}
+	return mlmodelSvc.MetadataFunc(ctx)
+}