Add tests for hypervisor/pci.go

- add test for pciDevice.readResources

Signed-off-by: Mikhail Malyshev <mike.malyshev@gmail.com>

Author: rucoder

pkg/pillar/hypervisor/pci_test.go

@@ -0,0 +1,57 @@
+// Copyright (c) 2025 Zededa, Inc.
+// SPDX-License-Identifier: Apache-2.0
+
+package hypervisor
+
+import (
+	"os"
+	"path/filepath"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestPCIReadResources(t *testing.T) {
+	t.Parallel()
+	// Create a temporary directory for our fake sysfs
+	tempDir, err := os.MkdirTemp("", "test-pci")
+	assert.NoError(t, err)
+	defer os.RemoveAll(tempDir) // Cleanup after test
+
+	// Create a fake PCI device directory
+	devicePath := filepath.Join(tempDir, "0000:00:1f.0")
+	err = os.MkdirAll(devicePath, 0755)
+	assert.NoError(t, err)
+
+	// Create mock resource file
+	resourceContent := "0x00000000fed40000 0x00000000fed44fff 0x0000000000040200\n" +
+		"0x00000000fec00000 0x00000000fec003ff 0x0000000000040200\n"
+
+	err = os.WriteFile(filepath.Join(devicePath, "resource"), []byte(resourceContent), 0644)
+	assert.NoError(t, err)
+
+	deviceAttributes := []string{"resource0", "resource1", "resource1_wc", "resource1_resize", "resource1_not_yet_exist"}
+
+	for _, attr := range deviceAttributes {
+		err = os.WriteFile(filepath.Join(devicePath, attr), []byte{}, 0644)
+		assert.NoError(t, err)
+	}
+
+	// Instantiate the PCI device and call readResources()
+	pciDev := pciDevice{pciLong: "0000:00:1f.0"}
+	resources, err := pciDev.readResources(tempDir)
+
+	// Assertions
+	assert.NoError(t, err)
+	assert.Len(t, resources, 2)
+
+	assert.Equal(t, uint64(0xfed40000), resources[0].start)
+	assert.Equal(t, uint64(0xfed44fff), resources[0].end)
+	assert.Equal(t, uint64(0x00040200), resources[0].flags)
+	assert.Equal(t, 0, resources[0].index)
+
+	assert.Equal(t, uint64(0xfec00000), resources[1].start)
+	assert.Equal(t, uint64(0xfec003ff), resources[1].end)
+	assert.Equal(t, uint64(0x00040200), resources[1].flags)
+	assert.Equal(t, 1, resources[1].index)
+}