From 85838ca6ddac6ab3f4c48d6e23a8c47924e9901b Mon Sep 17 00:00:00 2001
From: Adrian Sutton <adrian@oplabs.co>
Date: Mon, 17 Jul 2023 11:47:15 +1000
Subject: [PATCH] op-challenger: Add tests for Position attack and defend.

---
 op-challenger/fault/position_test.go | 54 ++++++++++++++++++++--------
 1 file changed, 39 insertions(+), 15 deletions(-)

diff --git a/op-challenger/fault/position_test.go b/op-challenger/fault/position_test.go
index dba505f92c0e..7ab6d6d8d1b4 100644
--- a/op-challenger/fault/position_test.go
+++ b/op-challenger/fault/position_test.go
@@ -36,27 +36,29 @@ type testNodeInfo struct {
 	Depth        int
 	IndexAtDepth int
 	TraceIndex   uint64
+	AttackGIndex uint64 // 0 indicates attack is not possible from this node
+	DefendGIndex uint64 // 0 indicates defend is not possible from this node
 }
 
 var treeNodesMaxDepth4 = []testNodeInfo{
-	{GIndex: 1, Depth: 0, IndexAtDepth: 0, TraceIndex: 15},
+	{GIndex: 1, Depth: 0, IndexAtDepth: 0, TraceIndex: 15, AttackGIndex: 2},
 
-	{GIndex: 2, Depth: 1, IndexAtDepth: 0, TraceIndex: 7},
-	{GIndex: 3, Depth: 1, IndexAtDepth: 1, TraceIndex: 15},
+	{GIndex: 2, Depth: 1, IndexAtDepth: 0, TraceIndex: 7, AttackGIndex: 4, DefendGIndex: 6},
+	{GIndex: 3, Depth: 1, IndexAtDepth: 1, TraceIndex: 15, AttackGIndex: 6},
 
-	{GIndex: 4, Depth: 2, IndexAtDepth: 0, TraceIndex: 3},
-	{GIndex: 5, Depth: 2, IndexAtDepth: 1, TraceIndex: 7},
-	{GIndex: 6, Depth: 2, IndexAtDepth: 2, TraceIndex: 11},
-	{GIndex: 7, Depth: 2, IndexAtDepth: 3, TraceIndex: 15},
+	{GIndex: 4, Depth: 2, IndexAtDepth: 0, TraceIndex: 3, AttackGIndex: 8, DefendGIndex: 10},
+	{GIndex: 5, Depth: 2, IndexAtDepth: 1, TraceIndex: 7, AttackGIndex: 10},
+	{GIndex: 6, Depth: 2, IndexAtDepth: 2, TraceIndex: 11, AttackGIndex: 12, DefendGIndex: 14},
+	{GIndex: 7, Depth: 2, IndexAtDepth: 3, TraceIndex: 15, AttackGIndex: 14},
 
-	{GIndex: 8, Depth: 3, IndexAtDepth: 0, TraceIndex: 1},
-	{GIndex: 9, Depth: 3, IndexAtDepth: 1, TraceIndex: 3},
-	{GIndex: 10, Depth: 3, IndexAtDepth: 2, TraceIndex: 5},
-	{GIndex: 11, Depth: 3, IndexAtDepth: 3, TraceIndex: 7},
-	{GIndex: 12, Depth: 3, IndexAtDepth: 4, TraceIndex: 9},
-	{GIndex: 13, Depth: 3, IndexAtDepth: 5, TraceIndex: 11},
-	{GIndex: 14, Depth: 3, IndexAtDepth: 6, TraceIndex: 13},
-	{GIndex: 15, Depth: 3, IndexAtDepth: 7, TraceIndex: 15},
+	{GIndex: 8, Depth: 3, IndexAtDepth: 0, TraceIndex: 1, AttackGIndex: 16, DefendGIndex: 18},
+	{GIndex: 9, Depth: 3, IndexAtDepth: 1, TraceIndex: 3, AttackGIndex: 18},
+	{GIndex: 10, Depth: 3, IndexAtDepth: 2, TraceIndex: 5, AttackGIndex: 20, DefendGIndex: 22},
+	{GIndex: 11, Depth: 3, IndexAtDepth: 3, TraceIndex: 7, AttackGIndex: 22},
+	{GIndex: 12, Depth: 3, IndexAtDepth: 4, TraceIndex: 9, AttackGIndex: 24, DefendGIndex: 26},
+	{GIndex: 13, Depth: 3, IndexAtDepth: 5, TraceIndex: 11, AttackGIndex: 26},
+	{GIndex: 14, Depth: 3, IndexAtDepth: 6, TraceIndex: 13, AttackGIndex: 28, DefendGIndex: 30},
+	{GIndex: 15, Depth: 3, IndexAtDepth: 7, TraceIndex: 15, AttackGIndex: 30},
 
 	{GIndex: 16, Depth: 4, IndexAtDepth: 0, TraceIndex: 0},
 	{GIndex: 17, Depth: 4, IndexAtDepth: 1, TraceIndex: 1},
@@ -95,3 +97,25 @@ func TestTraceIndex(t *testing.T) {
 		require.Equal(t, test.TraceIndex, result)
 	}
 }
+
+func TestAttack(t *testing.T) {
+	for _, test := range treeNodesMaxDepth4 {
+		if test.AttackGIndex == 0 {
+			continue
+		}
+		pos := NewPosition(test.Depth, test.IndexAtDepth)
+		result := pos.Attack()
+		require.Equalf(t, test.AttackGIndex, result.ToGIndex(), "Attack from GIndex %v", pos.ToGIndex())
+	}
+}
+
+func TestDefend(t *testing.T) {
+	for _, test := range treeNodesMaxDepth4 {
+		if test.DefendGIndex == 0 {
+			continue
+		}
+		pos := NewPosition(test.Depth, test.IndexAtDepth)
+		result := pos.Defend()
+		require.Equalf(t, test.DefendGIndex, result.ToGIndex(), "Defend from GIndex %v", pos.ToGIndex())
+	}
+}