public void WriteSpanningTwoMemoriesWithAGapThrowsButDoesWriteEverythingBeforeTheGap()
{
var mem = new VirtualMemory();
var ram1 = new FixedMemory(10);
var ram2 = new FixedMemory(10);
mem.Attach(0, ram1);
mem.Attach(15, ram2);
var buf = CreateData(15);
Assert.Throws <InvalidOperationException>(() => mem.Write(5, buf.Span));
// Part of our contract is that we WILL write everything we could before the gap!
Assert.Equal(
new byte[] { 0, 0, 0, 0, 0, 1, 2, 3, 4, 5 },
ram1.Data.ToArray()
);
// But not after the gap
Assert.Equal(
new byte[] { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },
ram2.Data.ToArray()
);
}
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 WriteContainedInOneMemory()
{
var mem = new VirtualMemory();
var ram1 = new FixedMemory(10);
mem.Attach(0, ram1);
var buf = CreateData(5);
mem.Write(1, buf.Span);
Assert.Equal(new byte[] { 0, 1, 2, 3, 4, 5, 0, 0, 0, 0 }, ram1.Data.ToArray());
}
public void WriteOutsideOfAnyMemoryThrows()
{
var mem = new VirtualMemory();
var ram1 = new FixedMemory(5);
var ram2 = new FixedMemory(5);
mem.Attach(0, ram1);
mem.Attach(20, ram2);
var buf = CreateData(5);
Assert.Throws <InvalidOperationException>(() => mem.Write(10, buf.Span));
}
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 WriteOverDetachedMemoryThrows()
{
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 = CreateData(15);
Assert.Throws <InvalidOperationException>(() => mem.Write(5, buf.Span));
}
public void WriteThatGoesOverTheEndThrows()
{
var mem = new VirtualMemory();
var buf = CreateData(20);
Assert.Throws <IndexOutOfRangeException>(() => mem.Write(0, buf.Span));
mem.Attach(0, new FixedMemory(5));
mem.Attach(5, new FixedMemory(5));
Assert.Throws <IndexOutOfRangeException>(() => mem.Write(0, buf.Span));
Assert.Throws <IndexOutOfRangeException>(() => mem.Write(7, buf.Span));
Assert.Throws <IndexOutOfRangeException>(() => mem.Write(15, buf.Span));
}
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 AttachAndDetachUpdateLength()
{
var mem = new VirtualMemory();
var ram1 = new FixedMemory(10);
var ram2 = new FixedMemory(5);
mem.Attach(10, ram1);
mem.Attach(20, ram2);
Assert.Equal(25, mem.Length);
mem.Detach(ram2);
Assert.Equal(20, mem.Length);
}
public void AttachThrowsIfMemoriesWouldOverlap()
{
var mem = new VirtualMemory();
var ram1 = new FixedMemory(10);
var ram2 = new FixedMemory(5);
mem.Attach(10, ram1);
// Dangling off the end
Assert.Throws <InvalidOperationException>(() => mem.Attach(18, ram2));
// Fully contained within
Assert.Throws <InvalidOperationException>(() => mem.Attach(11, ram2));
// Dangling off the start
Assert.Throws <InvalidOperationException>(() => mem.Attach(9, ram2));
}
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 WriteSpanningTwoAdjacentMemories()
{
var mem = new VirtualMemory();
var ram1 = new FixedMemory(10);
var ram2 = new FixedMemory(10);
mem.Attach(0, ram1);
mem.Attach(10, ram2);
var buf = CreateData(10);
mem.Write(5, buf.Span);
Assert.Equal(
new byte[] { 0, 0, 0, 0, 0, 1, 2, 3, 4, 5 },
ram1.Data.ToArray());
Assert.Equal(
new byte[] { 6, 7, 8, 9, 10, 0, 0, 0, 0, 0 },
ram2.Data.ToArray());
}
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);
}
public void InitialLengthIsZero()
{
var mem = new VirtualMemory();
Assert.Equal(0, mem.Length);
}