Add negative tests for all internal unit tests (task 348)

- internal/types: Fix StringValue panic with no null terminator,
  add negative tests for serialization, Equals, and StringValue edge cases
- internal/file: Add negative tests for empty name, unknown flags,
  SetFlags/AddFlags, Dup, empty OldnameNewname and Pathname
- internal/flamegraph: Add negative tests for StringByName unknown field,
  Counter.ValueByName panic, merge empty, deserialize invalid data,
  serialize/deserialize round-trip
- internal/generate/format: Add negative tests for empty input, ID errors,
  malformed fields, empty declarations
- internal/generate/typesgo: Add negative tests for snakeToCamel edge cases,
  unknown types, invalid member/define parsing, no-import case
- internal/generate/tracepointsgo: Add negative tests for malformed SEC,
  no SEC lines
- internal/generate/codegen: Add negative tests for unknown event kind,
  invalid syscall grouping, missing exit tracepoint
- internal/generate/classify: Add negative tests for empty external fields,
  non-fd types

Amp-Thread-ID: https://ampcode.com/threads/T-019c81bf-3d5c-7216-b1b6-890db1374414
Co-authored-by: Amp <amp@ampcode.com>

1 files changed, 86 insertions, 0 deletions

diff --git a/internal/file/file_test.go b/internal/file/file_test.go
index 726de5a..684a7d8 100644
--- a/internal/file/file_test.go
+++ b/internal/file/file_test.go
@@ -2,6 +2,8 @@ package file
 
 import (
 	"ior/internal/types"
+	"strings"
+	"syscall"
 	"testing"
 )
 
@@ -20,3 +22,87 @@ func TestNewFdUnknownFlags(t *testing.T) {
                 t.Errorf("expected unknown flags, got %v", fdFile.Flags())
         }
 }
+
+func TestNewFdEmptyName(t *testing.T) {
+        fdFile := NewFd(1, "", 0)
+        str := fdFile.String()
+        if !strings.Contains(str, "E:name") {
+                t.Errorf("expected String() to contain 'E:name' for empty name, got '%s'", str)
+        }
+}
+
+func TestFlagsIsUnknown(t *testing.T) {
+        f := unknownFlag
+        if f.Is(syscall.O_RDONLY) {
+                t.Errorf("expected Is(O_RDONLY) to be false for unknownFlag")
+        }
+        if f.Is(syscall.O_WRONLY) {
+                t.Errorf("expected Is(O_WRONLY) to be false for unknownFlag")
+        }
+        if f.Is(syscall.O_RDWR) {
+                t.Errorf("expected Is(O_RDWR) to be false for unknownFlag")
+        }
+}
+
+func TestFlagsStringUnknown(t *testing.T) {
+        f := Flags(-1)
+        if f.String() != "O_NONE" {
+                t.Errorf("expected 'O_NONE' for unknown flags, got '%s'", f.String())
+        }
+}
+
+func TestNewOldnameNewnameEmpty(t *testing.T) {
+        var oldname, newname [128]byte
+        f := NewOldnameNewname(oldname[:], newname[:])
+        if f.Name() != "" {
+                t.Errorf("expected empty Name(), got '%s'", f.Name())
+        }
+        if !strings.Contains(f.String(), "old:") || !strings.Contains(f.String(), "->new:") {
+                t.Errorf("expected String() to contain 'old:' and '->new:', got '%s'", f.String())
+        }
+}
+
+func TestNewPathnameEmpty(t *testing.T) {
+        var pathname [128]byte
+        f := NewPathname(pathname[:])
+        if f.Name() != "" {
+                t.Errorf("expected empty Name(), got '%s'", f.Name())
+        }
+        if !strings.Contains(f.String(), "pathname:") {
+                t.Errorf("expected String() to contain 'pathname:', got '%s'", f.String())
+        }
+}
+
+func TestFdFileSetFlags(t *testing.T) {
+        fdFile := NewFd(1, "test.txt", 0)
+        if fdFile.Flags() != Flags(0) {
+                t.Errorf("expected flags 0, got %v", fdFile.Flags())
+        }
+        fdFile.SetFlags(syscall.O_WRONLY)
+        if fdFile.Flags() != Flags(syscall.O_WRONLY) {
+                t.Errorf("expected O_WRONLY after SetFlags, got %v", fdFile.Flags())
+        }
+}
+
+func TestFdFileAddFlags(t *testing.T) {
+        fdFile := NewFd(1, "test.txt", syscall.O_RDWR)
+        fdFile.AddFlags(syscall.O_APPEND)
+        expected := Flags(syscall.O_RDWR | syscall.O_APPEND)
+        if fdFile.Flags() != expected {
+                t.Errorf("expected O_RDWR|O_APPEND after AddFlags, got %v", fdFile.Flags())
+        }
+}
+
+func TestFdFileDup(t *testing.T) {
+        fdFile := NewFd(1, "original.txt", syscall.O_RDONLY)
+        duped := fdFile.Dup(42)
+        if duped.Name() != "original.txt" {
+                t.Errorf("expected duped name 'original.txt', got '%s'", duped.Name())
+        }
+        if !strings.Contains(duped.String(), "42") {
+                t.Errorf("expected duped String() to contain fd 42, got '%s'", duped.String())
+        }
+        if strings.Contains(duped.String(), "%(1,") {
+                t.Errorf("expected duped String() to NOT contain old fd 1, got '%s'", duped.String())
+        }
+}