Added option to change delimiter

errors.go

@@ -97,6 +97,10 @@ import (
 	"io"
 )
 
+var (
+	delimiter string = ": "
+)
+
 // New returns an error with the supplied message.
 // New also records the stack trace at the point it was called.
 func New(message string) error {
@@ -238,7 +242,7 @@ type withMessage struct {
 	msg   string
 }
 
-func (w *withMessage) Error() string { return w.msg + ": " + w.cause.Error() }
+func (w *withMessage) Error() string { return w.msg + delimiter + w.cause.Error() }
 func (w *withMessage) Cause() error  { return w.cause }
 
 func (w *withMessage) Format(s fmt.State, verb rune) {
@@ -280,3 +284,7 @@ func Cause(err error) error {
 	}
 	return err
 }
+
+func SetDelimiter(d string) {
+	delimiter = d + " "
+}

errors_test.go

@@ -249,3 +249,30 @@ func TestErrorEquality(t *testing.T) {
 		}
 	}
 }
+
+func TestSetDelimiter(t *testing.T) {
+	tests := []struct {
+		name      string
+		delimiter string
+	}{
+		{"empty delimiter",
+			"",
+		},
+		{"single character delimiter",
+			"|",
+		},
+		{"string delimiter",
+			"delimiter",
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			SetDelimiter(tt.delimiter)
+			err := Wrap(New("foo"), "foo")
+			want := "foo" + tt.delimiter + " " + "foo"
+			if err.Error() != want {
+				t.Errorf("Error(): got: %s, want %s", err.Error(), want)
+			}
+		})
+	}
+}