test: Added test cases for empty strings in where clause

Author: Vasily Rodionov

delete.go

@@ -80,7 +80,7 @@ func (db *DeleteBuilder) DeleteFrom(table string) *DeleteBuilder {
 
 // Where sets expressions of WHERE in DELETE.
 func (db *DeleteBuilder) Where(andExpr ...string) *DeleteBuilder {
-	if len(andExpr) == 0 {
+	if len(andExpr) == 0 || estimateStringsBytes(andExpr) == 0 {
 		return db
 	}
 

select.go

@@ -189,7 +189,7 @@ func (sb *SelectBuilder) JoinWithOption(option JoinOption, table string, onExpr
 
 // Where sets expressions of WHERE in SELECT.
 func (sb *SelectBuilder) Where(andExpr ...string) *SelectBuilder {
-	if len(andExpr) == 0 {
+	if len(andExpr) == 0 || estimateStringsBytes(andExpr) == 0 {
 		return sb
 	}
 

update.go

@@ -97,7 +97,7 @@ func (ub *UpdateBuilder) SetMore(assignment ...string) *UpdateBuilder {
 
 // Where sets expressions of WHERE in UPDATE.
 func (ub *UpdateBuilder) Where(andExpr ...string) *UpdateBuilder {
-	if len(andExpr) == 0 {
+	if len(andExpr) == 0 || estimateStringsBytes(andExpr) == 0 {
 		return ub
 	}
 

whereclause_test.go

@@ -254,3 +254,60 @@ func TestEmptyWhereExpr(t *testing.T) {
 	a.Equal(ub.String(), "UPDATE t SET foo = 1")
 	a.Equal(db.String(), "DELETE FROM t")
 }
+
+func TestEmptyStringsWhere(t *testing.T) {
+	a := assert.New(t)
+	emptyExpr := []string{"", "", ""}
+
+	sb := Select("*").From("t").Where(emptyExpr...)
+	ub := Update("t").Set("foo = 1").Where(emptyExpr...)
+	db := DeleteFrom("t").Where(emptyExpr...)
+
+	a.Equal(sb.String(), "SELECT * FROM t")
+	a.Equal(ub.String(), "UPDATE t SET foo = 1")
+	a.Equal(db.String(), "DELETE FROM t")
+}
+
+func TestEmptyAddWhereExpr(t *testing.T) {
+	a := assert.New(t)
+	var emptyExpr []string
+	sb := Select("*").From("t")
+	ub := Update("t").Set("foo = 1")
+	db := DeleteFrom("t")
+
+	cond := NewCond()
+	whereClause := NewWhereClause().AddWhereExpr(
+		cond.Args,
+		emptyExpr...,
+	)
+
+	sb.AddWhereClause(whereClause)
+	ub.AddWhereClause(whereClause)
+	db.AddWhereClause(whereClause)
+
+	a.Equal(sb.String(), "SELECT * FROM t ")
+	a.Equal(ub.String(), "UPDATE t SET foo = 1 ")
+	a.Equal(db.String(), "DELETE FROM t ")
+}
+
+func TestEmptyStringsWhereAddWhereExpr(t *testing.T) {
+	a := assert.New(t)
+	emptyExpr := []string{"", "", ""}
+	sb := Select("*").From("t")
+	ub := Update("t").Set("foo = 1")
+	db := DeleteFrom("t")
+
+	cond := NewCond()
+	whereClause := NewWhereClause().AddWhereExpr(
+		cond.Args,
+		emptyExpr...,
+	)
+
+	sb.AddWhereClause(whereClause)
+	ub.AddWhereClause(whereClause)
+	db.AddWhereClause(whereClause)
+
+	a.Equal(sb.String(), "SELECT * FROM t ")
+	a.Equal(ub.String(), "UPDATE t SET foo = 1 ")
+	a.Equal(db.String(), "DELETE FROM t ")
+}