stack_test.go

package stack

import "testing"

func TestStackBasic(t *testing.T) {
	s := New[int](0)
	if s.Len() != 0 {
		t.Fatalf("len = %d", s.Len())
	}
	if _, ok := s.Pop(); ok {
		t.Fatal("pop on empty should be !ok")
	}

	s.Push(1)
	s.Push(2)
	s.Push(3)
	if s.Len() != 3 {
		t.Fatalf("len = %d", s.Len())
	}
	if v, _ := s.Peek(); v != 3 {
		t.Fatalf("peek = %d", v)
	}

	for _, want := range []int{3, 2, 1} {
		got, ok := s.Pop()
		if !ok || got != want {
			t.Fatalf("pop = %d %v, want %d", got, ok, want)
		}
	}
	if s.Len() != 0 {
		t.Fatalf("expected empty, got len=%d", s.Len())
	}
}

func TestStackZeroValue(t *testing.T) {
	var s Stack[string]
	s.Push("a")
	s.Push("b")
	if v, _ := s.Pop(); v != "b" {
		t.Errorf("got %q", v)
	}
}

func TestBalancedBrackets(t *testing.T) {
	cases := []struct {
		in   string
		want bool
	}{
		{"", true},
		{"()", true},
		{"()[]{}", true},
		{"([{}])", true},
		{"(", false},
		{")", false},
		{"([)]", false},
		{"hello (world [today])", true},
		{"a(b]c", false},
	}
	for _, tc := range cases {
		if got := BalancedBrackets(tc.in); got != tc.want {
			t.Errorf("BalancedBrackets(%q) = %v, want %v", tc.in, got, tc.want)
		}
	}
}