Enable methods to sort map keys and spew itself as last resort

If enabled by flags, try to use methods to stringify map keys and sort on that.

If we can't use primitive sorting and we can't use methods, we can still fall
back on spew itself.  If SpewKeys is enabled, use Sprintf("%#v") to generate a
string and sort by that.

1 files changed, 36 insertions, 1 deletions

diff --git a/spew/dump_test.go b/spew/dump_test.go
index 9e0e65f..3dd9089 100644
--- a/spew/dump_test.go
+++ b/spew/dump_test.go
@@ -64,9 +64,10 @@ package spew_test
 import (
 	"bytes"
 	"fmt"
-	"github.com/davecgh/go-spew/spew"
 	"testing"
 	"unsafe"
+
+	"github.com/davecgh/go-spew/spew"
 )
 
 // dumpTest is used to describe a test to be perfomed against the Dump method.
@@ -983,4 +984,38 @@ func TestDumpSortedKeys(t *testing.T) {
 	if s != expected {
 		t.Errorf("Sorted keys mismatch:\n  %v %v", s, expected)
 	}
+
+	s = cfg.Sdump(map[stringer]int{"1": 1, "3": 3, "2": 2})
+	expected = `(map[spew_test.stringer]int) (len=3) {
+(spew_test.stringer) (len=1) stringer 1: (int) 1,
+(spew_test.stringer) (len=1) stringer 2: (int) 2,
+(spew_test.stringer) (len=1) stringer 3: (int) 3
+}
+`
+	if s != expected {
+		t.Errorf("Sorted keys mismatch:\n  %v %v", s, expected)
+	}
+
+	s = cfg.Sdump(map[pstringer]int{pstringer("1"): 1, pstringer("3"): 3, pstringer("2"): 2})
+	expected = `(map[spew_test.pstringer]int) (len=3) {
+(spew_test.pstringer) (len=1) stringer 1: (int) 1,
+(spew_test.pstringer) (len=1) stringer 2: (int) 2,
+(spew_test.pstringer) (len=1) stringer 3: (int) 3
+}
+`
+	if s != expected {
+		t.Errorf("Sorted keys mismatch:\n  %v %v", s, expected)
+	}
+
+	s = cfg.Sdump(map[customError]int{customError(1): 1, customError(3): 3, customError(2): 2})
+	expected = `(map[spew_test.customError]int) (len=3) {
+(spew_test.customError) error: 1: (int) 1,
+(spew_test.customError) error: 2: (int) 2,
+(spew_test.customError) error: 3: (int) 3
+}
+`
+	if s != expected {
+		t.Errorf("Sorted keys mismatch:\n  %v %v", s, expected)
+	}
+
 }