add less operator

Author: LeandroSNunes

querybuilder/operator/less.go

@@ -0,0 +1,31 @@
+package operator
+
+import "time"
+
+func init() {
+	AddOperator(Less)
+}
+
+var Less = &Operator{
+	Name: "less",
+	Evaluate: func(input, value interface{}) bool {
+		if input == nil {
+			return false
+		}
+
+		switch value.(type) {
+		case float64:
+			return input.(float64) < value.(float64)
+		case int:
+			return input.(int) < value.(int)
+		case string:
+			return len(input.(string)) < len(value.(string))
+		case time.Time:
+			i := input.(time.Time)
+			v := value.(time.Time)
+			return i.Before(v)
+		default:
+			return false
+		}
+	},
+}

querybuilder/operator/less_test.go

@@ -0,0 +1,40 @@
+package operator
+
+import (
+	"testing"
+	"time"
+)
+
+func TestLess(t *testing.T) {
+	vdate := time.Date(2000, 1, 1, 15, 0, 0, 0, time.UTC)
+
+	var inputs = []struct {
+		title string
+		value interface{}
+		input interface{}
+		want  bool
+	}{
+		{title: "nil", input: nil, value: 3, want: false},
+		{title: "int =", input: 3, value: 3, want: false},
+		{title: "int <", input: 2, value: 3, want: true},
+		{title: "int >", input: 4, value: 3, want: false},
+		{title: "float =", input: float64(2.4), value: float64(2.4), want: false},
+		{title: "float <", input: float64(2.4), value: float64(2.5), want: true},
+		{title: "float >", input: float64(2.4), value: float64(1.4), want: false},
+		{title: "string =", input: "string", value: "string", want: false},
+		{title: "string <", input: "string", value: "mystring", want: true},
+		{title: "string >", input: "mystring", value: "string", want: false},
+		{title: "date =", input: time.Date(2000, 1, 1, 15, 0, 0, 0, time.UTC), value: vdate, want: false},
+		{title: "date <", input: time.Date(2000, 1, 1, 14, 59, 0, 0, time.UTC), value: vdate, want: true},
+		{title: "date >", input: time.Date(2000, 1, 1, 15, 1, 0, 0, time.UTC), value: vdate, want: false},
+	}
+
+	for _, input := range inputs {
+		t.Run(input.title, func(t *testing.T) {
+			got := Less.Evaluate(input.input, input.value)
+			if got != input.want {
+				t.Errorf("%v less %v got: %t, want: %t", input.input, input.value, got, input.want)
+			}
+		})
+	}
+}