Test Added

multi_key_test.go

@@ -0,0 +1,20 @@
+package etherscan
+
+import "testing"
+
+// TestgetKey may fail is you run test parallel
+func TestgetKey(t *testing.T) {
+	countApiKey, countBackupApiKey, k := 0, 0, ""
+	for i := 0; i < 10; i++ {
+		k = api.getKey()
+		if apiKey == k {
+			countApiKey++
+		} else if backupApiKey == k {
+			countBackupApiKey++
+		}
+	}
+	equal := countApiKey == 5 && countBackupApiKey == 5
+	if !equal {
+		t.Error("api.getKey not working")
+	}
+}

setup_e2e_test.go

@@ -9,30 +9,39 @@ package etherscan
 
 import (
 	"fmt"
+	"log"
 	"os"
 	"testing"
 	"time"
 )
 
-const apiKeyEnvName = "ETHERSCAN_API_KEY"
+const (
+	apiKeyEnvName       = "ETHERSCAN_API_KEY"
+	backupApiKeyEnvName = "BACKUP_ETHERSCAN_API_KEY"
+)
 
 var (
 	// api test client for many test cases
 	api *Client
 	// bucket default rate limiter
 	bucket *Bucket
 	// apiKey etherscan API key
-	apiKey string
+	apiKey       string
+	backupApiKey string
 )
 
 func init() {
 	apiKey = os.Getenv(apiKeyEnvName)
 	if apiKey == "" {
 		panic(fmt.Sprintf("API key is empty, set env variable %q with a valid API key to proceed.", apiKeyEnvName))
 	}
+	backupApiKey = os.Getenv(apiKeyEnvName)
+	if backupApiKey == "" {
+		log.Printf("WARN: Backup API key is empty, set env variable %q with a valid API key to proceed.", backupApiKeyEnvName)
+	}
 	bucket = NewBucket(500 * time.Millisecond)
 
-	api = New(Mainnet, []string{apiKey})
+	api = New(Mainnet, []string{apiKey, backupApiKey})
 	api.Verbose = true
 	api.BeforeRequest = func(module string, action string, param map[string]interface{}) error {
 		bucket.Take()