add String to Delta struct and use it in logs

Also switch to external package for slice_test as it was already a case
of "black box testing".

2 files changed, 59 insertions, 26 deletions

diff --git a/slice/slice.go b/slice/slice.go
index 05441c8..e5b959e 100644
--- a/slice/slice.go
+++ b/slice/slice.go
@@ -1,6 +1,9 @@
 package slice
 
-import "reflect"
+import (
+	"fmt"
+	"reflect"
+)
 
 type Slice []interface{}
 
@@ -11,11 +14,24 @@ type Ins struct {
 	Value []interface{}
 }
 
+type insData struct {
+	idx   int
+	count int
+}
+
 type Delta struct {
 	Del []Del
 	Ins []Ins
 }
 
+func (d Delta) String() string {
+	data := make([]insData, len(d.Ins))
+	for i, ins := range d.Ins {
+		data[i] = insData{ins.Idx, len(ins.Value)}
+	}
+	return fmt.Sprintf("{Del: %d Ins: %+v}", d.Del, data)
+}
+
 func Patch(source Slice, delta Delta) (target Slice) {
 	// apply Del part from patch to source into temp
 	size := len(source) - len(delta.Del)
diff --git a/slice/slice_test.go b/slice/slice_test.go
index d678fc7..8cb2a68 100644
--- a/slice/slice_test.go
+++ b/slice/slice_test.go
@@ -1,32 +1,33 @@
-package slice
+package slice_test
 
 import (
 	"testing"
 
+	"github.com/n-peugnet/dna-backup/slice"
 	"github.com/n-peugnet/dna-backup/testutils"
 )
 
 func TestPatch(t *testing.T) {
-	source := Slice{1, 2, 3, 4}
-	target := Slice{2, 5, 3, 6, 4, 7, 8}
-	patch := Diff(source, target)
-	testutils.AssertSame(t, []Del{0}, patch.Del, "Patch del part")
-	testutils.AssertSame(t, []Ins{
-		{1, Slice{5}},
-		{3, Slice{6}},
-		{5, Slice{7, 8}},
+	source := slice.Slice{1, 2, 3, 4}
+	target := slice.Slice{2, 5, 3, 6, 4, 7, 8}
+	patch := slice.Diff(source, target)
+	testutils.AssertSame(t, []slice.Del{0}, patch.Del, "Patch del part")
+	testutils.AssertSame(t, []slice.Ins{
+		{1, slice.Slice{5}},
+		{3, slice.Slice{6}},
+		{5, slice.Slice{7, 8}},
 	}, patch.Ins, "Patch ins part")
-	actual := Patch(source, patch)
+	actual := slice.Patch(source, patch)
 	testutils.AssertSame(t, target, actual, "Target obtained from patch application")
 }
 
 func TestEmptyPatch(t *testing.T) {
-	source := Slice{1, 2, 3, 4}
-	target := Slice{1, 2, 3, 4}
-	patch := Diff(source, target)
-	testutils.AssertSame(t, *new([]Del), patch.Del, "Patch del part")
-	testutils.AssertSame(t, *new([]Ins), patch.Ins, "Patch ins part")
-	actual := Patch(source, patch)
+	source := slice.Slice{1, 2, 3, 4}
+	target := slice.Slice{1, 2, 3, 4}
+	patch := slice.Diff(source, target)
+	testutils.AssertSame(t, *new([]slice.Del), patch.Del, "Patch del part")
+	testutils.AssertSame(t, *new([]slice.Ins), patch.Ins, "Patch ins part")
+	actual := slice.Patch(source, patch)
 	testutils.AssertSame(t, target, actual, "Target obtained from patch application")
 }
 
@@ -36,15 +37,31 @@ type i struct {
 
 func TestStruct(t *testing.T) {
 	c1, c2, c3, c4, c5, c6, c7, c8 := &i{1}, &i{2}, &i{3}, &i{4}, &i{5}, &i{6}, &i{7}, &i{8}
-	source := Slice{c1, c2, c3, c4}
-	target := Slice{&i{5}, c2, c5, c6, &i{4}, c7, &i{8}}
-	patch := Diff(source, target)
-	testutils.AssertSame(t, []Del{0, 2}, patch.Del, "Patch del part")
-	testutils.AssertSame(t, []Ins{
-		{0, Slice{c5}},
-		{2, Slice{c5, c6}},
-		{5, Slice{c7, c8}},
+	source := slice.Slice{c1, c2, c3, c4}
+	target := slice.Slice{&i{5}, c2, c5, c6, &i{4}, c7, &i{8}}
+	patch := slice.Diff(source, target)
+	testutils.AssertSame(t, []slice.Del{0, 2}, patch.Del, "Patch del part")
+	testutils.AssertSame(t, []slice.Ins{
+		{0, slice.Slice{c5}},
+		{2, slice.Slice{c5, c6}},
+		{5, slice.Slice{c7, c8}},
 	}, patch.Ins, "Patch ins part")
-	actual := Patch(source, patch)
+	actual := slice.Patch(source, patch)
 	testutils.AssertSame(t, target, actual, "Target obtained from patch application")
 }
+
+func TestDeltaString(t *testing.T) {
+	delta := slice.Delta{
+		Del: []slice.Del{0, 3, 4},
+		Ins: []slice.Ins{
+			{2, slice.Slice{6, 7, 8}},
+			{5, slice.Slice{5}},
+		},
+	}
+	testutils.AssertSame(
+		t,
+		"{Del: [0 3 4] Ins: [{idx:2 count:3} {idx:5 count:1}]}",
+		delta.String(),
+		"Delta string representation",
+	)
+}