diff --git a/driver/driver.go b/driver/driver.go
index 1675dd2..45c4b85 100644
--- a/driver/driver.go
+++ b/driver/driver.go
@@ -52,6 +52,11 @@ func (sqlite) Open(name string) (_ driver.Conn, err error) {
 	if err != nil {
 		return nil, err
 	}
+	defer func() {
+		if err != nil {
+			c.Close()
+		}
+	}()
 
 	var pragmas bool
 	c.txBegin = "BEGIN"
@@ -65,7 +70,6 @@ func (sqlite) Open(name string) (_ driver.Conn, err error) {
 			case "deferred", "immediate", "exclusive":
 				c.txBegin = "BEGIN " + s
 			default:
-				c.Close()
 				return nil, fmt.Errorf("sqlite3: invalid _txlock: %s", s)
 			}
 
@@ -73,9 +77,8 @@ func (sqlite) Open(name string) (_ driver.Conn, err error) {
 		}
 	}
 	if !pragmas {
-		err := c.Conn.Exec(`PRAGMA busy_timeout=60000`)
+		err = c.Conn.Exec(`PRAGMA busy_timeout=60000`)
 		if err != nil {
-			c.Close()
 			return nil, err
 		}
 		c.reusable = true
@@ -86,7 +89,6 @@ func (sqlite) Open(name string) (_ driver.Conn, err error) {
 				PRAGMA_query_only;
 		`)
 		if err != nil {
-			c.Close()
 			return nil, err
 		}
 		if s.Step() {
@@ -95,7 +97,6 @@ func (sqlite) Open(name string) (_ driver.Conn, err error) {
 		}
 		err = s.Close()
 		if err != nil {
-			c.Close()
 			return nil, err
 		}
 	}
diff --git a/ext/unicode/unicode_test.go b/ext/unicode/unicode_test.go
index 6d9b085..3f37ff4 100644
--- a/ext/unicode/unicode_test.go
+++ b/ext/unicode/unicode_test.go
@@ -2,6 +2,7 @@ package unicode
 
 import (
 	"errors"
+	"reflect"
 	"testing"
 
 	"github.com/ncruces/go-sqlite3"
@@ -62,6 +63,67 @@ func TestRegister(t *testing.T) {
 			}
 		})
 	}
+
+	err = db.Close()
+	if err != nil {
+		t.Fatal(err)
+	}
+}
+
+func TestRegister_collation(t *testing.T) {
+	t.Parallel()
+
+	db, err := sqlite3.Open(":memory:")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer db.Close()
+
+	Register(db)
+
+	err = db.Exec(`CREATE TABLE IF NOT EXISTS words (word VARCHAR(10))`)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	err = db.Exec(`INSERT INTO words (word) VALUES ('côte'), ('cote'), ('coter'), ('coté'), ('cotée'), ('côté')`)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	err = db.Exec(`SELECT icu_load_collation('fr_FR', 'french')`)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	stmt, _, err := db.Prepare(`SELECT word FROM words ORDER BY word COLLATE french`)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer stmt.Close()
+
+	got, want := []string{}, []string{"cote", "coté", "côte", "côté", "cotée", "coter"}
+
+	for stmt.Step() {
+		got = append(got, stmt.ColumnText(0))
+	}
+	if err := stmt.Err(); err != nil {
+		t.Fatal(err)
+	}
+
+	if !reflect.DeepEqual(got, want) {
+		t.Error("not equal")
+	}
+
+	err = stmt.Close()
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	err = db.Close()
+	if err != nil {
+		t.Fatal(err)
+	}
 }
 
 func TestRegister_error(t *testing.T) {
@@ -99,13 +161,31 @@ func TestRegister_error(t *testing.T) {
 		t.Errorf("got %v, want sqlite3.ERROR", err)
 	}
 
-	err = db.Exec(`SELECT 'hello' LIKE 'HELLO' ESCAPE '\\' `)
+	err = db.Exec(`SELECT 'hello' LIKE 'HELLO' ESCAPE '\\'`)
 	if err == nil {
 		t.Error("want error")
 	}
 	if !errors.Is(err, sqlite3.ERROR) {
 		t.Errorf("got %v, want sqlite3.ERROR", err)
 	}
+
+	err = db.Exec(`SELECT icu_load_collation('enUS', 'error')`)
+	if err == nil {
+		t.Error("want error")
+	}
+	if !errors.Is(err, sqlite3.ERROR) {
+		t.Errorf("got %v, want sqlite3.ERROR", err)
+	}
+
+	err = db.Exec(`SELECT icu_load_collation('enUS', '')`)
+	if err != nil {
+		t.Error(err)
+	}
+
+	err = db.Close()
+	if err != nil {
+		t.Fatal(err)
+	}
 }
 
 func Test_like2regex(t *testing.T) {
diff --git a/func_test.go b/func_test.go
index 4778b46..581e090 100644
--- a/func_test.go
+++ b/func_test.go
@@ -18,6 +18,7 @@ func ExampleConn_CreateCollation() {
 	if err != nil {
 		log.Fatal(err)
 	}
+	defer db.Close()
 
 	err = db.Exec(`CREATE TABLE IF NOT EXISTS words (word VARCHAR(10))`)
 	if err != nil {
@@ -46,16 +47,6 @@ func ExampleConn_CreateCollation() {
 	if err := stmt.Err(); err != nil {
 		log.Fatal(err)
 	}
-
-	err = stmt.Close()
-	if err != nil {
-		log.Fatal(err)
-	}
-
-	err = db.Close()
-	if err != nil {
-		log.Fatal(err)
-	}
 	// Output:
 	// cote
 	// coté
@@ -70,6 +61,7 @@ func ExampleConn_CreateFunction() {
 	if err != nil {
 		log.Fatal(err)
 	}
+	defer db.Close()
 
 	err = db.Exec(`CREATE TABLE IF NOT EXISTS words (word VARCHAR(10))`)
 	if err != nil {
@@ -100,16 +92,6 @@ func ExampleConn_CreateFunction() {
 	if err := stmt.Err(); err != nil {
 		log.Fatal(err)
 	}
-
-	err = stmt.Close()
-	if err != nil {
-		log.Fatal(err)
-	}
-
-	err = db.Close()
-	if err != nil {
-		log.Fatal(err)
-	}
 	// Unordered output:
 	// COTE
 	// COTÉ
@@ -124,6 +106,7 @@ func ExampleContext_SetAuxData() {
 	if err != nil {
 		log.Fatal(err)
 	}
+	defer db.Close()
 
 	err = db.Exec(`CREATE TABLE IF NOT EXISTS words (word VARCHAR(10))`)
 	if err != nil {
@@ -164,16 +147,6 @@ func ExampleContext_SetAuxData() {
 	if err := stmt.Err(); err != nil {
 		log.Fatal(err)
 	}
-
-	err = stmt.Close()
-	if err != nil {
-		log.Fatal(err)
-	}
-
-	err = db.Close()
-	if err != nil {
-		log.Fatal(err)
-	}
 	// Unordered output:
 	// cote
 	// côte
diff --git a/func_win_test.go b/func_win_test.go
index ef23bff..5832161 100644
--- a/func_win_test.go
+++ b/func_win_test.go
@@ -14,6 +14,7 @@ func ExampleConn_CreateWindowFunction() {
 	if err != nil {
 		log.Fatal(err)
 	}
+	defer db.Close()
 
 	err = db.Exec(`CREATE TABLE IF NOT EXISTS words (word VARCHAR(10))`)
 	if err != nil {
@@ -42,16 +43,6 @@ func ExampleConn_CreateWindowFunction() {
 	if err := stmt.Err(); err != nil {
 		log.Fatal(err)
 	}
-
-	err = stmt.Close()
-	if err != nil {
-		log.Fatal(err)
-	}
-
-	err = db.Close()
-	if err != nil {
-		log.Fatal(err)
-	}
 	// Output:
 	// 1
 	// 2