Adding Bytes() to get slice representation of ULID (#49)

* Adding Bytes() to get slice representation of ULID

* Added Test For Bytes()

* Added The Test For Bytes()

Author: sabify

Diff for: ulid.go

@@ -234,6 +234,11 @@ func MustParseStrict(ulid string) ULID {
 	return id
 }
 
+// Bytes returns bytes slice representation of ULID.
+func (u ULID) Bytes() []byte {
+	return u[:]
+}
+
 // String returns a lexicographically sortable string encoded ULID
 // (26 characters, non-standard base 32) e.g. 01AN4Z07BY79KA1307SR9X4MV3
 // Format: tttttttttteeeeeeeeeeeeeeee where t is time and e is entropy

Diff for: ulid_test.go

@@ -619,6 +619,17 @@ func TestMonotonicSafe(t *testing.T) {
 	}
 }
 
+func TestULID_Bytes(t *testing.T) {
+	tt := time.Unix(1000000, 0)
+	entropy := ulid.Monotonic(rand.New(rand.NewSource(tt.UnixNano())), 0)
+	id := ulid.MustNew(ulid.Timestamp(tt), entropy)
+	bid := id.Bytes()
+	bid[len(bid)-1]++
+	if bytes.Equal(id.Bytes(), bid) {
+		t.Error("Bytes() returned a reference to ulid underlying array!")
+	}
+}
+
 type safeMonotonicReader struct {
 	mtx sync.Mutex
 	ulid.MonotonicReader