add helper function and test coverage

aptos_test.go

@@ -69,3 +69,11 @@ func Test_AptosGetChainDetailsByChainIDAndFamily(t *testing.T) {
 		assert.Equal(t, v, details)
 	}
 }
+
+func Test_AptosGetChainIDByChainSelector(t *testing.T) {
+	for k, v := range aptosSelectorsMap {
+		chainID, err := GetChainIDFromSelector(v.ChainSelector)
+		assert.NoError(t, err)
+		assert.Equal(t, chainID, fmt.Sprintf("%v", k))
+	}
+}

evm_test.go

@@ -1,6 +1,7 @@
 package chain_selectors
 
 import (
+	"fmt"
 	"math/rand"
 	"strconv"
 	"testing"
@@ -235,3 +236,11 @@ func Test_EVMGetChainDetailsByChainIDAndFamily(t *testing.T) {
 		assert.Equal(t, v, details)
 	}
 }
+
+func Test_EVMGetChainIDByChainSelector(t *testing.T) {
+	for k, v := range evmSelectorsMap {
+		chainID, err := GetChainIDFromSelector(v.ChainSelector)
+		assert.NoError(t, err)
+		assert.Equal(t, chainID, fmt.Sprintf("%v", k))
+	}
+}

selectors.go

@@ -35,6 +35,37 @@ func GetSelectorFamily(selector uint64) (string, error) {
 	return "", fmt.Errorf("unknown chain selector %d", selector)
 }
 
+func GetChainIDFromSelector(selector uint64) (string, error) {
+	destChainFamily, err := GetSelectorFamily(selector)
+	if err != nil {
+		return "", err
+	}
+
+	var id uint64
+	var destChainID string
+	switch destChainFamily {
+	case FamilyEVM:
+		id, err = ChainIdFromSelector(selector)
+		if err != nil {
+			return "", fmt.Errorf("failed to get %v chain ID from selector %d: %w", destChainFamily, selector, err)
+		}
+		destChainID = fmt.Sprintf("%d", id)
+	case FamilySolana:
+		destChainID, err = SolanaChainIdFromSelector(selector)
+		if err != nil {
+			return "", fmt.Errorf("failed to get %v chain ID from selector %d: %w", destChainFamily, selector, err)
+		}
+	case FamilyAptos:
+		id, err = AptosChainIdFromSelector(selector)
+		if err != nil {
+			return "", fmt.Errorf("failed to get %v chain ID from selector %d: %w", destChainFamily, selector, err)
+		}
+		destChainID = fmt.Sprintf("%d", id)
+	}
+
+	return destChainID, nil
+}
+
 func GetChainDetailsByChainIDAndFamily(chainID string, family string) (ChainDetails, error) {
 	switch family {
 	case FamilyEVM:

solana_test.go

@@ -1,6 +1,7 @@
 package chain_selectors
 
 import (
+	"fmt"
 	"math/rand"
 	"testing"
 
@@ -75,3 +76,11 @@ func Test_SolanaGetChainDetailsByChainIDAndFamily(t *testing.T) {
 		assert.Equal(t, v, details)
 	}
 }
+
+func Test_SolanaGetChainIDByChainSelector(t *testing.T) {
+	for k, v := range solanaSelectorsMap {
+		chainID, err := GetChainIDFromSelector(v.ChainSelector)
+		assert.NoError(t, err)
+		assert.Equal(t, chainID, fmt.Sprintf("%v", k))
+	}
+}