Add test for utils sorting function

outputs/utils_test.go

@@ -0,0 +1,69 @@
+package outputs
+
+import (
+	"reflect"
+	"testing"
+)
+
+func Test_getSortedStringKeys(t *testing.T) {
+	type args struct {
+		m map[string]interface{}
+	}
+	tests := []struct {
+		name string
+		args args
+		want []string
+	}{
+		{
+			name: "basic sort",
+			args: args{
+				m: map[string]interface{}{
+					"b": "foo",
+					"c": "baz",
+					"a": "bar",
+				},
+			},
+			want: []string{"a", "b", "c"},
+		},
+		{
+			name: "In place sort",
+			args: args{
+				m: map[string]interface{}{
+					"a": "",
+					"b": "",
+					"c": "",
+				},
+			},
+			want: []string{"a", "b", "c"},
+		},
+		{
+			name: "Non-string emission",
+			args: args{
+				m: map[string]interface{}{
+					"a": "a",
+					"b": 2,
+					"c": "c",
+				},
+			},
+			want: []string{"a", "c"},
+		},
+		{
+			name: "Non-string emission - empty result",
+			args: args{
+				m: map[string]interface{}{
+					"a": 1,
+					"b": 2,
+					"c": 3,
+				},
+			},
+			want: nil,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if got := getSortedStringKeys(tt.args.m); !reflect.DeepEqual(got, tt.want) {
+				t.Errorf("getSortedStringKeys() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}