feat(errorsx): introduce NewTopLevelGenericErrWrapper (ooni#511)

Part of ooni/probe#1733 and diff has been
extracted from ooni#506.

internal/netxlite/errorsx/errwrapper.go

@@ -92,3 +92,9 @@ func NewErrWrapper(c Classifier, op string, err error) *ErrWrapper {
  WrappedErr: err,
  }
 }
+
+// NewTopLevelGenericErrWrapper wraps an error occurring at top
+// level using the most generic available classifier.
+func NewTopLevelGenericErrWrapper(err error) *ErrWrapper {
+ return NewErrWrapper(ClassifyGenericError, TopLevelOperation, err)
+}

internal/netxlite/errorsx/errwrapper_test.go

@@ -102,3 +102,19 @@ func TestNewErrWrapper(t *testing.T) {
  }
  })
 }
+
+func TestNewTopLevelGenericErrWrapper(t *testing.T) {
+ out := NewTopLevelGenericErrWrapper(io.EOF)
+ if out.Failure != FailureEOFError {
+ t.Fatal("invalid failure")
+ }
+ if out.Operation != TopLevelOperation {
+ t.Fatal("invalid operation")
+ }
+ if !errors.Is(out, io.EOF) {
+ t.Fatal("invalid underlying error using errors.Is")
+ }
+ if !errors.Is(out.WrappedErr, io.EOF) {
+ t.Fatal("invalid WrappedErr")
+ }
+}