package util

import (
	"reflect"
	"testing"
)

func TestDedupeStrings(t *testing.T) {
	tests := []struct {
		name     string
		input    []string
		expected []string
	}{
		{"nil stays nil", nil, nil},
		{"empty slice", []string{}, []string{}},
		{"nothing repeated", []string{"a", "b", "c"}, []string{"a", "b", "c"}},
		{"all one value", []string{"a", "a", "a"}, []string{"a"}},
		{"repeats next to each other", []string{"a", "a", "b", "b"}, []string{"a", "b"}},
		{"repeats far apart", []string{"a", "b", "a", "c", "b"}, []string{"a", "b", "c"}},
		{"empty string is a value", []string{"", "a", ""}, []string{"", "a"}},
	}

	for _, test := range tests {
		t.Run(test.name, func(t *testing.T) {
			got := DedupeStrings(test.input)
			if !reflect.DeepEqual(got, test.expected) {
				t.Errorf("expected %#v got %#v", test.expected, got)
			}
		})
	}
}

func TestDedupeStringsLeavesInputAlone(t *testing.T) {
	input := []string{"b", "a", "b"}
	DedupeStrings(input)

	if !reflect.DeepEqual(input, []string{"b", "a", "b"}) {
		t.Errorf("expected the input to be unchanged, got %#v", input)
	}
}