From 7028c95ed0cb2ffeb08e14f18e6674fab19d034c Mon Sep 17 00:00:00 2001
From: rcourtman <courtmanr@gmail.com>
Date: Thu, 9 Apr 2026 21:28:37 +0100
Subject: [PATCH] Hermeticize Linux SMART discovery tests

---
 .../hostagent/collector_observability_test.go   |  7 +++++++
 internal/hostagent/smartctl_coverage_test.go    | 17 +++++++++++++++--
 2 files changed, 22 insertions(+), 2 deletions(-)

diff --git a/internal/hostagent/collector_observability_test.go b/internal/hostagent/collector_observability_test.go
index ed072c938..c0058d734 100644
--- a/internal/hostagent/collector_observability_test.go
+++ b/internal/hostagent/collector_observability_test.go
@@ -5,6 +5,7 @@ import (
 	"context"
 	"encoding/json"
 	"errors"
+	"os"
 	"os/exec"
 	"strings"
 	"testing"
@@ -17,13 +18,16 @@ func TestCollectLocal_LogsStructuredContextOnDeviceCollectionFailure(t *testing.
 	origRun := smartRunCommandOutput
 	origLook := execLookPath
 	origGOOS := runtimeGOOS
+	origReadDir := readDir
 	t.Cleanup(func() {
 		smartRunCommandOutput = origRun
 		execLookPath = origLook
 		runtimeGOOS = origGOOS
+		readDir = origReadDir
 	})
 
 	runtimeGOOS = "linux"
+	readDir = func(string) ([]os.DirEntry, error) { return nil, errors.New("sysfs unavailable") }
 	execLookPath = func(string) (string, error) { return "smartctl", nil }
 	smartRunCommandOutput = func(ctx context.Context, name string, args ...string) ([]byte, error) {
 		if name == "lsblk" {
@@ -62,10 +66,13 @@ func TestCollectLocal_LogsStructuredContextOnDeviceCollectionFailure(t *testing.
 
 func TestListBlockDevicesLinux_LogsStructuredContextForExcludedDevice(t *testing.T) {
 	origRun := smartRunCommandOutput
+	origReadDir := readDir
 	t.Cleanup(func() {
 		smartRunCommandOutput = origRun
+		readDir = origReadDir
 	})
 
+	readDir = func(string) ([]os.DirEntry, error) { return nil, errors.New("sysfs unavailable") }
 	smartRunCommandOutput = func(ctx context.Context, name string, args ...string) ([]byte, error) {
 		data := lsblkJSON{Blockdevices: []lsblkDevice{
 			{Name: "sda", Type: "disk", Tran: "sata", Subsystems: "block:scsi:pci"},
diff --git a/internal/hostagent/smartctl_coverage_test.go b/internal/hostagent/smartctl_coverage_test.go
index 8acd76c7d..62e2ea058 100644
--- a/internal/hostagent/smartctl_coverage_test.go
+++ b/internal/hostagent/smartctl_coverage_test.go
@@ -466,14 +466,17 @@ func TestCollectSMARTLocalSkipsErrors(t *testing.T) {
 	origRun := smartRunCommandOutput
 	origLook := execLookPath
 	origNow := timeNow
+	origReadDir := readDir
 	t.Cleanup(func() {
 		smartRunCommandOutput = origRun
 		execLookPath = origLook
 		timeNow = origNow
+		readDir = origReadDir
 	})
 
 	fixed := time.Date(2024, 1, 2, 3, 4, 5, 0, time.UTC)
 	timeNow = func() time.Time { return fixed }
+	readDir = func(string) ([]os.DirEntry, error) { return nil, errors.New("sysfs unavailable") }
 	execLookPath = func(string) (string, error) { return "smartctl", nil }
 
 	smartRunCommandOutput = func(ctx context.Context, name string, args ...string) ([]byte, error) {
@@ -926,8 +929,13 @@ func TestCollectDeviceSMARTWWN(t *testing.T) {
 
 func TestListBlockDevicesLinuxWithExcludes(t *testing.T) {
 	origRun := smartRunCommandOutput
-	t.Cleanup(func() { smartRunCommandOutput = origRun })
+	origReadDir := readDir
+	t.Cleanup(func() {
+		smartRunCommandOutput = origRun
+		readDir = origReadDir
+	})
 
+	readDir = func(string) ([]os.DirEntry, error) { return nil, errors.New("sysfs unavailable") }
 	smartRunCommandOutput = func(ctx context.Context, name string, args ...string) ([]byte, error) {
 		if name != "lsblk" {
 			return nil, errors.New("unexpected command")
@@ -1045,8 +1053,13 @@ func TestLinuxSMARTSkipReason(t *testing.T) {
 
 func TestListBlockDevicesLinuxFiltersVirtualDevices(t *testing.T) {
 	origRun := smartRunCommandOutput
-	t.Cleanup(func() { smartRunCommandOutput = origRun })
+	origReadDir := readDir
+	t.Cleanup(func() {
+		smartRunCommandOutput = origRun
+		readDir = origReadDir
+	})
 
+	readDir = func(string) ([]os.DirEntry, error) { return nil, errors.New("sysfs unavailable") }
 	smartRunCommandOutput = func(ctx context.Context, name string, args ...string) ([]byte, error) {
 		return mockLsblkJSON(
 			lsblkDevice{Name: "sda", Type: "disk", Tran: "sata", Subsystems: "block:scsi:pci"},