From 2a618231061ab4052940313e2cc54916677a6bfb Mon Sep 17 00:00:00 2001
From: Pieter Joost <pj@born2code.net>
Date: Fri, 6 Dec 2019 22:25:32 +0100
Subject: [PATCH] iimplement fmt.Stringer interface on Subspace

---
 bindings/go/src/fdb/subspace/subspace.go      | 10 ++++++++++
 bindings/go/src/fdb/subspace/subspace_test.go | 15 +++++++++++++++
 2 files changed, 25 insertions(+)
 create mode 100644 bindings/go/src/fdb/subspace/subspace_test.go

diff --git a/bindings/go/src/fdb/subspace/subspace.go b/bindings/go/src/fdb/subspace/subspace.go
index 353d377e42..b621d058c7 100644
--- a/bindings/go/src/fdb/subspace/subspace.go
+++ b/bindings/go/src/fdb/subspace/subspace.go
@@ -35,6 +35,8 @@ package subspace
 import (
 	"bytes"
 	"errors"
+	"fmt"
+
 	"github.com/apple/foundationdb/bindings/go/src/fdb"
 	"github.com/apple/foundationdb/bindings/go/src/fdb/tuple"
 )
@@ -42,6 +44,8 @@ import (
 // Subspace represents a well-defined region of keyspace in a FoundationDB
 // database.
 type Subspace interface {
+	fmt.Stringer
+
 	// Sub returns a new Subspace whose prefix extends this Subspace with the
 	// encoding of the provided element(s). If any of the elements are not a
 	// valid tuple.TupleElement, Sub will panic.
@@ -105,6 +109,12 @@ func FromBytes(b []byte) Subspace {
 	return subspace{s}
 }
 
+// String implements the fmt.Stringer interface and return the subspace
+// as a human readable byte string provided by fdb.Printable.
+func (s subspace) String() string {
+	return fdb.Printable(s.b)
+}
+
 func (s subspace) Sub(el ...tuple.TupleElement) Subspace {
 	return subspace{concat(s.Bytes(), tuple.Tuple(el).Pack()...)}
 }
diff --git a/bindings/go/src/fdb/subspace/subspace_test.go b/bindings/go/src/fdb/subspace/subspace_test.go
new file mode 100644
index 0000000000..33a4164697
--- /dev/null
+++ b/bindings/go/src/fdb/subspace/subspace_test.go
@@ -0,0 +1,15 @@
+package subspace
+
+import (
+	"fmt"
+	"testing"
+)
+
+func TestSubspaceString(t *testing.T) {
+	printed := fmt.Sprint(Sub([]byte("hello"), "world", 42, 0x99))
+	expected := "\\x01hello\\x00\\x02world\\x00\\x15*\\x15\\x99"
+
+	if printed != expected {
+		t.Fatalf("printed subspace result differs, expected %v, got %v", expected, printed)
+	}
+}