add test cases

update_test.go

@@ -5,6 +5,7 @@ package sqlbuilder
 
 import (
 	"fmt"
+	"testing"
 )
 
 func ExampleUpdateBuilder() {
@@ -33,3 +34,26 @@ func ExampleUpdateBuilder() {
 	// UPDATE demo.user SET type = ?, credit = credit + 1, modified_at = UNIX_TIMESTAMP(NOW()) WHERE id > ? AND name LIKE ? AND (id_card IS NULL OR status IN (?, ?, ?)) AND modified_at > created_at + ?
 	// [sys 1234 %Du 1 2 5 86400]
 }
+
+func TestUpdateAssignments(t *testing.T) {
+	cases := map[string]func(ub *UpdateBuilder) string{
+		"f = f + 1|[]":     func(ub *UpdateBuilder) string { return ub.Incr("f") },
+		"f = f - 1|[]":     func(ub *UpdateBuilder) string { return ub.Decr("f") },
+		"f = f + $0|[123]": func(ub *UpdateBuilder) string { return ub.Add("f", 123) },
+		"f = f - $0|[123]": func(ub *UpdateBuilder) string { return ub.Sub("f", 123) },
+		"f = f * $0|[123]": func(ub *UpdateBuilder) string { return ub.Mul("f", 123) },
+		"f = f / $0|[123]": func(ub *UpdateBuilder) string { return ub.Div("f", 123) },
+	}
+
+	for expected, f := range cases {
+		ub := NewUpdateBuilder()
+		s := f(ub)
+		ub.Set(s)
+		_, args := ub.Build()
+		actual := fmt.Sprintf("%v|%v", s, args)
+
+		if actual != expected {
+			t.Fatalf("invalid assignment result. [expected:%v] [actual:%v]", expected, actual)
+		}
+	}
+}