public void ReadThatGoesOverTheEndThrows()
{
var mem = new VirtualMemory();
var buf = new byte[20];
Assert.Throws <IndexOutOfRangeException>(() => mem.Read(0, buf));
mem.Attach(0, new FixedMemory(5));
mem.Attach(5, new FixedMemory(5));
Assert.Throws <IndexOutOfRangeException>(() => mem.Read(0, buf));
Assert.Throws <IndexOutOfRangeException>(() => mem.Read(7, buf));
Assert.Throws <IndexOutOfRangeException>(() => mem.Read(15, buf));
}
public void ReadContainedInOneMemory()
{
var mem = new VirtualMemory();
var ram1 = CreateFixedMemory(10);
mem.Attach(0, ram1);
var buf = new byte[5];
mem.Read(1, buf);
Assert.Equal(new byte[] { 2, 3, 4, 5, 6 }, buf);
}
public void ReadSpanningTwoAdjacentMemories()
{
var mem = new VirtualMemory();
var ram1 = CreateFixedMemory(10);
var ram2 = CreateFixedMemory(10);
mem.Attach(0, ram1);
mem.Attach(10, ram2);
var buf = new byte[5];
mem.Read(8, buf);
Assert.Equal(new byte[] { 9, 10, 1, 2, 3 }, buf);
}
public void ReadOutsideOfAnyMemoryProducesAllZeros()
{
var mem = new VirtualMemory();
var ram1 = CreateFixedMemory(5);
var ram2 = CreateFixedMemory(5);
mem.Attach(0, ram1);
mem.Attach(20, ram2);
var buf = new byte[5];
mem.Read(10, buf);
Assert.True(buf.All(b => b == 0));
}
public void ReadSpanningTwoMemoriesWithAGap()
{
var mem = new VirtualMemory();
var ram1 = CreateFixedMemory(10);
var ram2 = CreateFixedMemory(10);
mem.Attach(0, ram1);
mem.Attach(15, ram2);
var buf = new byte[15];
mem.Read(5, buf);
Assert.Equal(new byte[] {
6, 7, 8, 9, 10,
0, 0, 0, 0, 0,
1, 2, 3, 4, 5
}, buf);
}
public void ReadDoesNotIncludeDetachedMemory()
{
var mem = new VirtualMemory();
var ram1 = CreateFixedMemory(10);
var ram2 = CreateFixedMemory(10);
mem.Attach(0, ram1);
mem.Attach(15, ram2);
mem.Detach(ram1);
var buf = new byte[15];
mem.Read(5, buf);
Assert.Equal(new byte[] {
0, 0, 0, 0, 0,
0, 0, 0, 0, 0,
1, 2, 3, 4, 5
}, buf);
}