get sql state from interface (#38)

error.go

@@ -16,13 +16,14 @@ func contains(xs []string, x string) bool {
 	return false
 }
 
+type sqlState interface {
+	SQLState() string
+}
+
 // IsErrorCode checks is error has given code
 func IsErrorCode(err error, code string) bool {
-	var pqErr *pq.Error
-	if errors.As(err, &pqErr) && string(pqErr.Code) == code {
-		return true
-	}
-	return false
+	sErr, ok := err.(sqlState)
+	return ok && sErr.SQLState() == code
 }
 
 // IsErrorClass checks is error has given class
@@ -52,7 +53,7 @@ func IsInvalidTextRepresentation(err error) bool {
 	return IsErrorCode(err, "22P02")
 }
 
-// IsCharacterNotInRepertoire checks is error an character_not_in_repertoire
+// IsCharacterNotInRepertoire checks is error a character_not_in_repertoire
 func IsCharacterNotInRepertoire(err error) bool {
 	return IsErrorCode(err, "22021")
 }
@@ -75,7 +76,7 @@ func IsQueryCanceled(err error) bool {
 	return IsErrorCode(err, "57014")
 }
 
-// IsSerializationFailure checks is error an serialization_failure error
+// IsSerializationFailure checks is error a serialization_failure error
 // (pq: could not serialize access due to read/write dependencies among transactions)
 func IsSerializationFailure(err error) bool {
 	return IsErrorCode(err, "40001")

tx.go

@@ -4,8 +4,6 @@ import (
 	"context"
 	"database/sql"
 	"errors"
-
-	"github.com/lib/pq"
 )
 
 // ErrAbortTx rollbacks transaction and return nil error
@@ -79,8 +77,7 @@ func RunInTxContext(ctx context.Context, db BeginTxer, opts *TxOptions, fn func(
 		if err == nil || errors.Is(err, ErrAbortTx) {
 			return nil
 		}
-		var pqErr *pq.Error
-		if retryable := errors.As(err, &pqErr) && (pqErr.Code == "40001"); !retryable {
+		if !IsSerializationFailure(err) {
 			return err
 		}
 	}

tx_test.go

@@ -7,7 +7,6 @@ import (
 	"math/rand"
 	"sync"
 	"testing"
-	"time"
 
 	"github.com/acoshift/pgsql"
 )
@@ -118,7 +117,6 @@ func TestTx(t *testing.T) {
 	}
 
 	wg := sync.WaitGroup{}
-	rand.Seed(time.Now().Unix())
 	for i := 0; i < 1000; i++ {
 		wg.Add(1)
 		go func() {