diff --git a/engine/engine_executor.go b/engine/engine_executor.go
index 5c50f77..eac7941 100644
--- a/engine/engine_executor.go
+++ b/engine/engine_executor.go
@@ -346,7 +346,7 @@ func executeGlobalVariableStatement(
 	env *ast.Environment,
 	statement *ast.GlobalVariableStatement,
 ) error {
-	value, err := EvaluateExpression(env, nil, nil, nil)
+	value, err := EvaluateExpression(env, statement.Value, []string{}, nil)
 	if err != nil {
 		return err
 	}
diff --git a/engine/engine_executor_test.go b/engine/engine_executor_test.go
index 00a22ef..cbe1d48 100644
--- a/engine/engine_executor_test.go
+++ b/engine/engine_executor_test.go
@@ -1 +1,307 @@
 package engine
+
+import (
+	"fmt"
+	"testing"
+
+	"github.com/ggql/ggql/ast"
+	"github.com/go-git/go-git/v5"
+)
+
+const path = "F:/tt/test.git"
+
+func TestExecuteStatement(t *testing.T) {
+	env := ast.Environment{
+		Globals:      map[string]ast.Value{},
+		GlobalsTypes: map[string]ast.DataType{},
+		Scopes:       map[string]ast.DataType{},
+	}
+
+	statement := &ast.SelectStatement{
+		TableName:    "commits",
+		FieldsNames:  []string{"commit_id", "title", "message", "name", "email", "datetime", "repo"},
+		FieldsValues: []ast.Expression{},
+		AliasTable:   make(map[string]string),
+		IsDistinct:   false,
+	}
+
+	if err := TestNewRepo(path); err != nil {
+		t.Fatal("failed to create repo:", err)
+	}
+	repo, err := git.PlainOpen(path)
+	if err != nil {
+		t.Fatal("failed to open repo")
+	}
+
+	var object ast.GitQLObject
+	var table map[string]string
+	selection := []string{}
+
+	ret := ExecuteStatement(&env, statement, repo, &object, table, selection)
+	if ret == nil {
+		t.Log("execute statement succeeded")
+	} else {
+		t.Errorf("execute statement failed: %v", ret)
+	}
+
+	if err := TestDeleteRepo(path); err != nil {
+		t.Fatal("failed to delete repo:", err)
+	}
+}
+
+func TestExecuteSelectStatement(t *testing.T) {
+	env := ast.Environment{
+		Globals:      map[string]ast.Value{},
+		GlobalsTypes: map[string]ast.DataType{},
+		Scopes:       map[string]ast.DataType{},
+	}
+
+	statement := &ast.SelectStatement{
+		TableName:    "commits",
+		FieldsNames:  []string{"commit_id", "title", "message", "name", "email", "datetime", "repo"},
+		FieldsValues: []ast.Expression{},
+		AliasTable:   make(map[string]string),
+		IsDistinct:   false,
+	}
+
+	if err := TestNewRepo(path); err != nil {
+		t.Fatal("failed to create repo:", err)
+	}
+	repo, err := git.PlainOpen(path)
+	if err != nil {
+		t.Fatal("failed to open repo")
+	}
+
+	var object ast.GitQLObject
+	selections := []string{}
+
+	ret := executeSelectStatement(&env, statement, repo, &object, selections)
+	if ret == nil {
+		t.Log("execute statement succeeded")
+	} else {
+		t.Errorf("execute statement failed: %v", ret)
+	}
+
+	if err := TestDeleteRepo(path); err != nil {
+		t.Fatal("failed to delete repo:", err)
+	}
+}
+
+func TestExecuteWhereStatement(t *testing.T) {
+	env := ast.Environment{
+		Globals:      map[string]ast.Value{},
+		GlobalsTypes: map[string]ast.DataType{},
+		Scopes:       map[string]ast.DataType{},
+	}
+	statement := &ast.WhereStatement{
+		Condition: &ast.NumberExpression{Value: ast.IntegerValue{Value: 1}},
+	}
+
+	var object ast.GitQLObject
+	object.Titles = []string{"title1", "title2"}
+	object.Groups = []ast.Group{
+		{Rows: []ast.Row{
+			{Values: []ast.Value{
+				ast.IntegerValue{Value: 1}, ast.IntegerValue{Value: 2},
+			}},
+			{Values: []ast.Value{
+				ast.IntegerValue{Value: 3}, ast.IntegerValue{Value: 4},
+			}},
+		}},
+	}
+
+	ret := executeWhereStatement(&env, statement, &object)
+	if ret == nil {
+		t.Log("execute statement succeeded")
+	} else {
+		t.Errorf("execute statement failed: %v", ret)
+	}
+}
+
+func TestExecuteHavingStatement(t *testing.T) {
+	env := ast.Environment{
+		Globals:      map[string]ast.Value{},
+		GlobalsTypes: map[string]ast.DataType{},
+		Scopes:       map[string]ast.DataType{},
+	}
+	statement := &ast.HavingStatement{
+		Condition: &ast.NumberExpression{Value: ast.IntegerValue{Value: 1}},
+	}
+	var object ast.GitQLObject
+	object.Titles = []string{"title1", "title2"}
+	object.Groups = []ast.Group{
+		{Rows: []ast.Row{
+			{Values: []ast.Value{
+				ast.IntegerValue{Value: 1}, ast.IntegerValue{Value: 2},
+			}},
+			{Values: []ast.Value{
+				ast.IntegerValue{Value: 3}, ast.IntegerValue{Value: 4},
+			}},
+		}},
+	}
+	ret := executeHavingStatement(&env, statement, &object)
+	if ret == nil {
+		t.Log("execute statement succeeded")
+	} else {
+		t.Errorf("execute statement failed: %v", ret)
+	}
+}
+
+func TestExecuteLimitStatement(t *testing.T) {
+	statement := &ast.LimitStatement{
+		Count: 0,
+	}
+	var object ast.GitQLObject
+	object.Titles = []string{"title1", "title2"}
+	object.Groups = []ast.Group{
+		{Rows: []ast.Row{
+			{Values: []ast.Value{
+				ast.IntegerValue{Value: 1}, ast.IntegerValue{Value: 2},
+			}},
+			{Values: []ast.Value{
+				ast.IntegerValue{Value: 3}, ast.IntegerValue{Value: 4},
+			}},
+		}},
+	}
+	ret := executeLimitStatement(statement, &object)
+	if ret == nil {
+		t.Log("execute statement succeeded")
+	} else {
+		t.Errorf("execute statement failed: %v", ret)
+	}
+}
+
+func TestExecuteOffsetStatement(t *testing.T) {
+	statement := &ast.OffsetStatement{
+		Count: 0,
+	}
+	var object ast.GitQLObject
+	object.Titles = []string{"title1", "title2"}
+	object.Groups = []ast.Group{
+		{Rows: []ast.Row{
+			{Values: []ast.Value{
+				ast.IntegerValue{Value: 1}, ast.IntegerValue{Value: 2},
+			}},
+			{Values: []ast.Value{
+				ast.IntegerValue{Value: 3}, ast.IntegerValue{Value: 4},
+			}},
+		}},
+	}
+	ret := executeOffsetStatement(statement, &object)
+	if ret == nil {
+		t.Log("execute statement succeeded")
+	} else {
+		t.Errorf("execute statement failed: %v", ret)
+	}
+}
+
+func TestExecuteOrderByStatement(t *testing.T) {
+	env := ast.Environment{
+		Globals:      map[string]ast.Value{},
+		GlobalsTypes: map[string]ast.DataType{},
+		Scopes:       map[string]ast.DataType{},
+	}
+	statement := &ast.OrderByStatement{
+		Arguments:     []ast.Expression{&ast.NumberExpression{Value: ast.IntegerValue{Value: 5}}},
+		SortingOrders: []ast.SortingOrder{ast.Ascending},
+	}
+	var object ast.GitQLObject
+	object.Titles = []string{"title1", "title2"}
+	object.Groups = []ast.Group{
+		{Rows: []ast.Row{
+			{Values: []ast.Value{
+				ast.IntegerValue{Value: 1}, ast.IntegerValue{Value: 2},
+			}},
+			{Values: []ast.Value{
+				ast.IntegerValue{Value: 3}, ast.IntegerValue{Value: 4},
+			}},
+		}},
+	}
+	ret := executeOrderByStatement(&env, statement, &object)
+	if ret == nil {
+		t.Log("execute statement succeeded")
+	} else {
+		t.Errorf("execute statement failed: %v", ret)
+	}
+}
+
+func TestExecuteGroupByStatement(t *testing.T) {
+	statement := &ast.GroupByStatement{
+		FieldName: "title1",
+	}
+	var object ast.GitQLObject
+	object.Titles = []string{"title1", "title2"}
+	object.Groups = []ast.Group{
+		{Rows: []ast.Row{
+			{Values: []ast.Value{
+				ast.IntegerValue{Value: 1}, ast.IntegerValue{Value: 2},
+			}},
+			{Values: []ast.Value{
+				ast.IntegerValue{Value: 3}, ast.IntegerValue{Value: 4},
+			}},
+		}},
+	}
+	ret := executeGroupByStatement(statement, &object)
+	if ret == nil {
+		t.Log("execute statement succeeded")
+	} else {
+		t.Errorf("execute statement failed: %v", ret)
+	}
+}
+
+func TestExecuteAggregationFunctionStatement(t *testing.T) {
+	env := ast.Environment{
+		Globals:      map[string]ast.Value{},
+		GlobalsTypes: map[string]ast.DataType{},
+		Scopes:       map[string]ast.DataType{},
+	}
+	statement := &ast.AggregationsStatement{
+		Aggregations: make(map[string]ast.AggregateValue),
+	}
+	var a ast.AggregateValue
+	a.Function.Name = "max"
+	a.Function.Arg = "title3"
+
+	statement.Aggregations["title"] = a
+	var object ast.GitQLObject
+	object.Titles = []string{"title1", "title2"}
+	object.Groups = []ast.Group{
+		{Rows: []ast.Row{
+			{Values: []ast.Value{
+				ast.IntegerValue{Value: 1}, ast.IntegerValue{Value: 2},
+			}},
+			{Values: []ast.Value{
+				ast.IntegerValue{Value: 3}, ast.IntegerValue{Value: 4},
+			}},
+		}},
+	}
+	table := make(map[string]string)
+	table["title"] = "title1"
+	fmt.Println("5")
+	ret := executeAggregationFunctionStatement(&env, statement, &object, table)
+	fmt.Println("3")
+	if ret == nil {
+		t.Log("execute statement succeeded")
+	} else {
+		t.Errorf("execute statement failed: %v", ret)
+	}
+}
+
+func TestExecuteGlobalVariableStatement(t *testing.T) {
+	env := ast.Environment{
+		Globals:      map[string]ast.Value{},
+		GlobalsTypes: map[string]ast.DataType{},
+		Scopes:       map[string]ast.DataType{},
+	}
+	statement := &ast.GlobalVariableStatement{
+		Name:  "name",
+		Value: &ast.NumberExpression{Value: ast.IntegerValue{Value: 1}},
+	}
+
+	ret := executeGlobalVariableStatement(&env, statement)
+	if ret == nil {
+		t.Log("execute statement succeeded")
+	} else {
+		t.Errorf("execute statement failed: %v", ret)
+	}
+}
diff --git a/engine/test.go b/engine/test.go
new file mode 100644
index 0000000..59a6a25
--- /dev/null
+++ b/engine/test.go
@@ -0,0 +1,18 @@
+package engine
+
+import (
+	"os"
+
+	"github.com/go-git/go-git/v5"
+)
+
+func TestNewRepo(path string) error {
+	// Clone the given repository to the given path
+	_, err := git.PlainInit(path, true)
+	return err
+}
+
+func TestDeleteRepo(path string) error {
+	err := os.RemoveAll(path)
+	return err
+}