fpc-comet/tests/test_frame.pas

{ test_frame -- pure TMemoryStream-driven exercise of cm.frame.

  No sockets, no auth, no protocol state -- builds canned byte
  sequences and asserts the parser decodes them correctly,
  plus round-trips frames through the writer. }

program test_frame;

{$mode objfpc}{$H+}
{$modeswitch advancedrecords}

uses
  Classes, SysUtils, cm.types, cm.frame;

var
  TestsRun, TestsFailed: Integer;

procedure Check(Cond: Boolean; const Msg: string);
begin
  Inc(TestsRun);
  if not Cond then
  begin
    Inc(TestsFailed);
    Writeln('  FAIL: ', Msg);
  end;
end;

procedure TestEmptyPayload;
var
  MS: TMemoryStream;
  F1, F2: TCometFrame;
begin
  Writeln('TestEmptyPayload');
  MS := TMemoryStream.Create;
  try
    { INIT with no payload (won't happen in real protocol but
      exercises the zero-length payload path). }
    F1.InitPayload(NPKT_IDLE, 0, F2 { dummy }, 0);
    CMWriteFrame(MS, F1);

    Check(MS.Size = 4 + 2 + 4,
      'empty-payload frame is 10 bytes (LEN+TYPE+SEQ+CRC)');

    MS.Position := 0;
    Check(CMReadFrame(MS, F2), 'round-trip empty payload');
    Check(F2.PktType = NPKT_IDLE, 'PktType preserved');
    Check(F2.Seq = 0, 'Seq preserved');
    Check(Length(F2.Payload) = 0, 'payload still empty');
  finally
    MS.Free;
  end;
end;

procedure TestSmallPayload;
var
  MS: TMemoryStream;
  F1, F2: TCometFrame;
  Body:   array[0..15] of Byte;
  I:      Integer;
begin
  Writeln('TestSmallPayload');
  for I := 0 to 15 do Body[I] := Byte(I * 17 + 1);
  MS := TMemoryStream.Create;
  try
    F1.InitPayload(NPKT_FINFO, 7, Body, 16);
    CMWriteFrame(MS, F1);

    MS.Position := 0;
    Check(CMReadFrame(MS, F2), 'round-trip 16-byte payload');
    Check(F2.PktType = NPKT_FINFO, 'PktType preserved');
    Check(F2.Seq = 7, 'Seq preserved');
    Check(Length(F2.Payload) = 16, 'payload length preserved');
    Check(CompareByte(F2.Payload[0], Body[0], 16) = 0,
      'payload bytes preserved');
  finally
    MS.Free;
  end;
end;

procedure TestLargePayload;
var
  MS: TMemoryStream;
  F1, F2: TCometFrame;
  Body:   array[0..16383] of Byte;
  I:      Integer;
begin
  Writeln('TestLargePayload');
  for I := 0 to 16383 do Body[I] := Byte(I and $FF);
  MS := TMemoryStream.Create;
  try
    F1.InitPayload(NPKT_DATA, 42, Body, 16384);
    CMWriteFrame(MS, F1);

    Check(MS.Size = 4 + 2 + 16384 + 4,
      '16K-payload frame size = LEN + TYPE+SEQ + 16K + CRC');

    MS.Position := 0;
    Check(CMReadFrame(MS, F2), 'round-trip 16K payload');
    Check(Length(F2.Payload) = 16384, 'large payload length');
    Check(CompareByte(F2.Payload[0], Body[0], 16384) = 0,
      'large payload bytes preserved');
  finally
    MS.Free;
  end;
end;

procedure TestPartialReadReturnsFalse;
var
  MS: TMemoryStream;
  F1, F2: TCometFrame;
  Body:   array[0..7] of Byte;
  I:      Integer;
  Wire:   TBytes;
begin
  Writeln('TestPartialReadReturnsFalse');
  for I := 0 to 7 do Body[I] := Byte(I);

  { Build a complete frame in memory, then strip trailing
    bytes so the reader sees a partial. }
  MS := TMemoryStream.Create;
  try
    F1.InitPayload(NPKT_DATA, 1, Body, 8);
    CMWriteFrame(MS, F1);
    SetLength(Wire, MS.Size);
    MS.Position := 0;
    MS.Read(Wire[0], MS.Size);
  finally
    MS.Free;
  end;

  { Truncate to half its bytes. }
  MS := TMemoryStream.Create;
  try
    MS.WriteBuffer(Wire[0], Length(Wire) div 2);
    MS.Position := 0;
    Check(not CMReadFrame(MS, F2),
      'half-frame returns False (not raise)');
    Check(MS.Position = 0,
      'partial-read rewinds for caller to retry');
  finally
    MS.Free;
  end;
end;

procedure TestBadCRCRaises;
var
  MS:  TMemoryStream;
  F1, F2: TCometFrame;
  Body: array[0..7] of Byte;
  I:    Integer;
  Raised: Boolean;
  Wire: TBytes;
begin
  Writeln('TestBadCRCRaises');
  for I := 0 to 7 do Body[I] := Byte(I);

  MS := TMemoryStream.Create;
  try
    F1.InitPayload(NPKT_DATA, 1, Body, 8);
    CMWriteFrame(MS, F1);
    SetLength(Wire, MS.Size);
    MS.Position := 0;
    MS.Read(Wire[0], MS.Size);
  finally
    MS.Free;
  end;

  { Flip a bit in the payload -- CRC should fail. }
  Wire[6] := Wire[6] xor $01;

  MS := TMemoryStream.Create;
  try
    MS.WriteBuffer(Wire[0], Length(Wire));
    MS.Position := 0;
    Raised := False;
    try
      CMReadFrame(MS, F2);
    except
      on ECometFrameError do Raised := True;
    end;
    Check(Raised, 'corrupted payload raises ECometFrameError');
  finally
    MS.Free;
  end;
end;

procedure TestPacketName;
begin
  Writeln('TestPacketName');
  Check(CMPacketName(NPKT_INIT) = 'NPKT_INIT', 'INIT name');
  Check(CMPacketName(NPKT_DATA) = 'NPKT_DATA', 'DATA name');
  Check(CMPacketName(NPKT_LSTREQ) = 'NPKT_LSTREQ', 'LSTREQ name');
  Check(CMPacketName($AB) = 'NPKT_AB', 'unknown code fallback');
end;

begin
  TestsRun := 0;
  TestsFailed := 0;

  TestEmptyPayload;
  TestSmallPayload;
  TestLargePayload;
  TestPartialReadReturnsFalse;
  TestBadCRCRaises;
  TestPacketName;

  Writeln;
  Writeln(Format('%d tests run, %d failed', [TestsRun, TestsFailed]));
  if TestsFailed > 0 then Halt(1);
end.