diff --git a/tests/init.go b/tests/init.go
index f9af5c0ca..a18e12bdd 100644
--- a/tests/init.go
+++ b/tests/init.go
@@ -75,6 +75,18 @@ var Forks = map[string]*params.ChainConfig{
 		ConstantinopleBlock: big.NewInt(0),
 		PetersburgBlock:     big.NewInt(0),
 	},
+	"Istanbul": {
+		ChainID:             big.NewInt(1),
+		HomesteadBlock:      big.NewInt(0),
+		EIP150Block:         big.NewInt(0),
+		EIP155Block:         big.NewInt(0),
+		EIP158Block:         big.NewInt(0),
+		DAOForkBlock:        big.NewInt(0),
+		ByzantiumBlock:      big.NewInt(0),
+		ConstantinopleBlock: big.NewInt(0),
+		PetersburgBlock:     big.NewInt(0),
+		IstanbulBlock:       big.NewInt(0),
+	},
 	"FrontierToHomesteadAt5": {
 		ChainID:        big.NewInt(1),
 		HomesteadBlock: big.NewInt(5),
@@ -117,6 +129,17 @@ var Forks = map[string]*params.ChainConfig{
 		ConstantinopleBlock: big.NewInt(5),
 		PetersburgBlock:     big.NewInt(5),
 	},
+	"ConstantinopleFixToIstanbulAt5": {
+		ChainID:             big.NewInt(1),
+		HomesteadBlock:      big.NewInt(0),
+		EIP150Block:         big.NewInt(0),
+		EIP155Block:         big.NewInt(0),
+		EIP158Block:         big.NewInt(0),
+		ByzantiumBlock:      big.NewInt(0),
+		ConstantinopleBlock: big.NewInt(0),
+		PetersburgBlock:     big.NewInt(0),
+		IstanbulBlock:       big.NewInt(5),
+	},
 }
 
 // UnsupportedForkError is returned when a test requests a fork that isn't implemented.