Added duplicated trigger validation (#3124)

utils/utils_test.go

@@ -0,0 +1,30 @@
+// Copyright (c) 2016 Mattermost, Inc. All Rights Reserved.
+// See License.txt for license information.
+
+package utils
+
+import (
+	"testing"
+)
+
+func TestStringArrayIntersection(t *testing.T) {
+	a := []string{
+		"abc",
+		"def",
+		"ghi",
+	}
+	b := []string{
+		"jkl",
+	}
+	c := []string{
+		"def",
+	}
+
+	if len(StringArrayIntersection(a, b)) != 0 {
+		t.Fatal("should be 0")
+	}
+
+	if len(StringArrayIntersection(a, c)) != 1 {
+		t.Fatal("should be 1")
+	}
+}