From fde025ef7ce40b8cac95fd677a03e6e63ba1e220 Mon Sep 17 00:00:00 2001
From: Joni Collinge <jonathancollinge@live.com>
Date: Thu, 25 Oct 2018 09:31:06 +0100
Subject: [PATCH] added test to validate expected behavior

---
 pipeline/error_test.go | 32 ++++++++++++++++++++++++++++++++
 1 file changed, 32 insertions(+)
 create mode 100644 pipeline/error_test.go

diff --git a/pipeline/error_test.go b/pipeline/error_test.go
new file mode 100644
index 0000000..7c69882
--- /dev/null
+++ b/pipeline/error_test.go
@@ -0,0 +1,32 @@
+package pipeline
+
+import (
+	"testing"
+
+	"github.com/pkg/errors"
+)
+
+func TestErrorWithCause(t *testing.T) {
+	rootErr := errors.New("root cause error")
+	pipeErr := NewError(rootErr, "pipeline wrapper error")
+	wrapErr := errors.Wrap(pipeErr, "wrap with stack trace")
+	causeErr := errors.Cause(wrapErr)
+	if causeErr == nil {
+		t.Fatal("cause error should not be nil")
+	}
+	if causeErr != rootErr {
+		t.Fatal("cause error should be the same as root error")
+	}
+}
+
+func TestErrorWithoutCause(t *testing.T) {
+	pipeErr := NewError(nil, "pipeline error without cause")
+	wrapErr := errors.Wrap(pipeErr, "wrap with stack trace")
+	causeErr := errors.Cause(wrapErr)
+	if causeErr == nil {
+		t.Fatal("cause error should not be nil")
+	}
+	if causeErr != pipeErr {
+		t.Fatal("cause error should be the same as pipeline error")
+	}
+}