add contains operator

Author: LeandroSNunes

querybuilder/operator/contains.go

@@ -0,0 +1,34 @@
+package operator
+
+import (
+	"reflect"
+	"strings"
+)
+
+func init() {
+	AddOperator(Contains)
+}
+
+var Contains = &Operator{
+	Name: "contains",
+	Evaluate: func(input, value interface{}) bool {
+		rinput := reflect.ValueOf(input)
+
+		switch rinput.Kind() {
+		case reflect.String:
+			if strings.Contains(input.(string), value.(string)) {
+				return true
+			}
+		case reflect.Slice:
+			for i := 0; i < rinput.Len(); i++ {
+				if rinput.Index(i).Interface() == value {
+					return true
+				}
+			}
+		default:
+			return false
+		}
+
+		return false
+	},
+}

querybuilder/operator/contains_test.go

@@ -0,0 +1,29 @@
+package operator
+
+import "testing"
+
+func TestContains(t *testing.T) {
+	var inputs = []struct {
+		title string
+		value interface{}
+		input interface{}
+		want  bool
+	}{
+		{title: "contains-1", value: "word to", input: "my word to match", want: true},
+		{title: "contains-2", value: "my", input: "my word to match", want: true},
+		{title: "contains-3", value: "myword", input: "my word to match", want: false},
+		{title: "contains-4", value: 2, input: []int{1, 2, 3}, want: true},
+		{title: "contains-5", value: 2.5, input: []float64{2.0, 2.3, 2.5, 3}, want: true},
+		{title: "contains-6", value: "c", input: []string{"a", "b", "c"}, want: true},
+		{title: "contains-7", value: "d", input: []string{"a", "b", "c"}, want: false},
+	}
+
+	for _, input := range inputs {
+		t.Run(input.title, func(t *testing.T) {
+			got := Contains.Evaluate(input.input, input.value)
+			if got != input.want {
+				t.Errorf("%v contains %v got: %t, want: %t", input.input, input.value, got, input.want)
+			}
+		})
+	}
+}