diff --git a/ext/blobio/blob_test.go b/ext/blobio/blob_test.go
index 3caac21..9a754de 100644
--- a/ext/blobio/blob_test.go
+++ b/ext/blobio/blob_test.go
@@ -78,6 +78,13 @@ func Test_readblob(t *testing.T) {
 		t.Log(err)
 	}
 
+	err = db.Exec(`SELECT readblob('main', 'test1', 'col', 1, 1, 1)`)
+	if err == nil {
+		t.Fatal("want error")
+	} else {
+		t.Log(err)
+	}
+
 	err = db.Exec(`
 		CREATE TABLE test1 (col);
 		CREATE TABLE test2 (col);
@@ -88,6 +95,18 @@ func Test_readblob(t *testing.T) {
 		t.Fatal(err)
 	}
 
+	err = db.Exec(`SELECT readblob('main', 'test1', 'col', 1, -1, 1)`)
+	if err == nil {
+		t.Fatal("want error")
+	} else {
+		t.Log(err)
+	}
+
+	err = db.Exec(`SELECT readblob('main', 'test1', 'col', 1, 1, 0)`)
+	if err != nil {
+		t.Log(err)
+	}
+
 	stmt, _, err := db.Prepare(`SELECT readblob('main', value, 'col', 1, 1, 1) FROM array(?)`)
 	if err != nil {
 		t.Fatal(err)
@@ -119,6 +138,51 @@ func Test_readblob(t *testing.T) {
 	}
 }
 
+func Test_writeblob(t *testing.T) {
+	t.Parallel()
+
+	db, err := sqlite3.Open(":memory:")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer db.Close()
+
+	err = db.Exec(`SELECT writeblob()`)
+	if err == nil {
+		t.Fatal("want error")
+	} else {
+		t.Log(err)
+	}
+
+	err = db.Exec(`SELECT writeblob('main', 'test', 'col', 1, 1, x'')`)
+	if err == nil {
+		t.Fatal("want error")
+	} else {
+		t.Log(err)
+	}
+
+	err = db.Exec(`
+		CREATE TABLE test (col);
+		INSERT INTO test VALUES (x'cafe');
+		-- INSERT INTO test2 VALUES (x'babe');
+	`)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	err = db.Exec(`SELECT writeblob('main', 'test', 'col', 1, -1, x'')`)
+	if err == nil {
+		t.Fatal("want error")
+	} else {
+		t.Log(err)
+	}
+
+	err = db.Exec(`SELECT writeblob('main', 'test', 'col', 1, 0, x'babe')`)
+	if err != nil {
+		t.Log(err)
+	}
+}
+
 func Test_openblob(t *testing.T) {
 	t.Parallel()
 
@@ -135,6 +199,13 @@ func Test_openblob(t *testing.T) {
 		t.Log(err)
 	}
 
+	err = db.Exec(`SELECT openblob('main', 'test1', 'col', 1, false, NULL)`)
+	if err == nil {
+		t.Fatal("want error")
+	} else {
+		t.Log(err)
+	}
+
 	err = db.Exec(`
 		CREATE TABLE test1 (col);
 		CREATE TABLE test2 (col);
diff --git a/tests/func_test.go b/tests/func_test.go
index 5b324ed..130c419 100644
--- a/tests/func_test.go
+++ b/tests/func_test.go
@@ -48,6 +48,7 @@ func TestCreateFunction(t *testing.T) {
 		case 10:
 			ctx.ResultNull()
 		case 11:
+			arg.NoChange()
 			ctx.ResultError(sqlite3.FULL)
 		}
 	})
diff --git a/tests/stmt_test.go b/tests/stmt_test.go
index be13044..7542673 100644
--- a/tests/stmt_test.go
+++ b/tests/stmt_test.go
@@ -611,10 +611,40 @@ func TestStmt_ColumnTime(t *testing.T) {
 			t.Errorf("want error")
 		}
 	}
+}
+
+func TestStmt_ColumnValue(t *testing.T) {
+	t.Parallel()
+
+	db, err := sqlite3.Open(":memory:")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer db.Close()
+
+	stmt, _, err := db.Prepare(`SELECT 1`)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer stmt.Close()
+
+	if stmt.Step() {
+		val := stmt.ColumnValue(0)
+		if _, err := val.InFirst(); err == nil {
+			t.Error("want error")
+		}
+		if _, err := val.InNext(); err == nil {
+			t.Error("want error")
+		}
+	}
 
 	if got := stmt.Status(sqlite3.STMTSTATUS_RUN, true); got != 1 {
 		t.Errorf("got %d, want 1", got)
 	}
+
+	if got := stmt.Status(math.MaxUint32, false); got != 0 {
+		t.Errorf("got %d, want 0", got)
+	}
 }
 
 func TestStmt_Error(t *testing.T) {