package main

import (
	"testing"
)

func TestMemWrite(t *testing.T) {
	m := Memory{
		intern: make(map[int]int),
	}

	// write in some memory, not starting at the head
	err := m.Write(1, []int{1, 2, 3})
	if err != nil {
		t.Log(err.Error())
		t.Fail()
	}
	// only three values in memory
	if len(m.intern) != 3 {
		t.Fail()
	}
	if m.NextFreeAddress() != 4 {
		t.Log("expected nextFree to be 4, got", m.nextFree)
		t.Fail()
	}

	// can't write to negative addresses
	if m.Write(-1, []int{1}) == nil {
		t.Fail()
	}
}

func TestMemRead(t *testing.T) {
	m := Memory{
		intern: map[int]int{0: 1, 1: 2, 2: 3, 100: 101},
	}

	// Read two known locations
	r := m.Read(0, 2)
	if len(r) != 2 {
		t.Fail()
	}
	if r[0] != 1 || r[1] != 2 {
		t.Fail()
	}

	// Read past known memory
	r2 := m.Read(100, 2)
	if len(r2) != 2 {
		t.Fail()
	}
	if r2[0] != 101 || r2[1] != 0 {
		t.Fail()
	}

	// read empty memory
	m2 := Memory{
		intern: map[int]int{},
	}
	r3 := m2.Read(0, 100)
	if len(r3) != 100 {
		t.Fail()
	}
	for i := range r3 {
		if r3[i] != 0 {
			t.Fail()
		}
	}
}