[#106] test: Generate correct data for tests

Some tests are using invalid data that do not meet the requirements of the
FrostFS protocol, e.g.
- Container/Object IDs aren't 32 bytes long
- Signature key and sign have invalid length
- Split IDs aren't valid UUIDv4
and etc.

Signed-off-by: Aleksey Savchuk <a.savchuk@yadro.com>

session/test/generate.go

@@ -1,6 +1,7 @@
 package sessiontest
 
 import (
+	crand "crypto/rand"
 	"math/rand"
 	"time"
 
@@ -38,7 +39,10 @@ func GenerateCreateResponseBody(empty bool) *session.CreateResponseBody {
 	m := new(session.CreateResponseBody)
 
 	if !empty {
-		m.SetID([]byte{1, 2, 3})
+		id := make([]byte, 16)
+		_, _ = crand.Read(id)
+
+		m.SetID(id)
 		m.SetSessionKey([]byte{4, 5, 6})
 	}
 
@@ -164,7 +168,10 @@ func GenerateSessionTokenBody(empty bool) *session.TokenBody {
 	m := new(session.TokenBody)
 
 	if !empty {
-		m.SetID([]byte{1})
+		id := make([]byte, 16)
+		_, _ = crand.Read(id)
+
+		m.SetID(id)
 		m.SetSessionKey([]byte{2})
 		m.SetOwnerID(refstest.GenerateOwnerID(false))
 		m.SetLifetime(GenerateTokenLifetime(false))