src/pkg/cosboot/bzimage_test.go

// Copyright 2026 Google LLC
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//      http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package cosboot

import (
	"testing"
)

// createPE creates a minimal PE/COFF file that can be interpreted by debug/pe.
// This includes a minimal MS-DOS stub, Signature, and the part of the COFF file
// header necessary to determine architecture.
//
// More details: https://learn.microsoft.com/en-us/windows/win32/debug/pe-format#ms-dos-stub-image-only
func createPE(machine uint16) []byte {
	// Minimal PE header
	data := make([]byte, 0x80)
	// DOS header
	copy(data[0:], "MZ")
	// Set file offset to PE signature
	data[0x3c] = 0x40
	// PE signature
	copy(data[0x40:], "PE\x00\x00")
	// COFF header starts at 0x44
	// Machine (little endian)
	data[0x44] = byte(machine)
	data[0x45] = byte(machine >> 8)
	return data
}

func TestEFIArch_Success(t *testing.T) {
	tests := []struct {
		name string
		img  []byte
		want string
	}{
		{
			name: "x86_64",
			img:  createPE(0x8664),
			want: "x86_64",
		},
		{
			name: "arm64",
			img:  createPE(0xAA64),
			want: "arm64",
		},
	}
	for _, test := range tests {
		test := test
		t.Run(test.name, func(t *testing.T) {
			got, err := EFIArch(test.img)
			if err != nil {
				t.Fatalf("archFromImage() error = %v, want nil", err)
				return
			}
			if got != test.want {
				t.Errorf("archFromImage() = %v, want %v", got, test.want)
			}
		})
	}
}

func TestEFIArch_Failure(t *testing.T) {
	if got, err := EFIArch([]byte("invalid")); err == nil {
		t.Fatalf("archFromImage() = %v, want error", got)
	}
}