diff --git a/internal/cmd/dev/cmd_vm.go b/internal/cmd/dev/cmd_vm.go
index 71a4ac23..52ef2104 100644
--- a/internal/cmd/dev/cmd_vm.go
+++ b/internal/cmd/dev/cmd_vm.go
@@ -9,6 +9,7 @@ import (
 	"github.com/host-uk/core/pkg/cli"
 	"github.com/host-uk/core/pkg/devops"
 	"github.com/host-uk/core/pkg/i18n"
+	"github.com/host-uk/core/pkg/io"
 )
 
 // addVMCommands adds the dev environment VM commands to the dev parent command.
@@ -40,7 +41,7 @@ func addVMInstallCommand(parent *cli.Command) {
 }
 
 func runVMInstall() error {
-	d, err := devops.New()
+	d, err := devops.New(io.Local)
 	if err != nil {
 		return err
 	}
@@ -112,7 +113,7 @@ func addVMBootCommand(parent *cli.Command) {
 }
 
 func runVMBoot(memory, cpus int, fresh bool) error {
-	d, err := devops.New()
+	d, err := devops.New(io.Local)
 	if err != nil {
 		return err
 	}
@@ -163,7 +164,7 @@ func addVMStopCommand(parent *cli.Command) {
 }
 
 func runVMStop() error {
-	d, err := devops.New()
+	d, err := devops.New(io.Local)
 	if err != nil {
 		return err
 	}
@@ -204,7 +205,7 @@ func addVMStatusCommand(parent *cli.Command) {
 }
 
 func runVMStatus() error {
-	d, err := devops.New()
+	d, err := devops.New(io.Local)
 	if err != nil {
 		return err
 	}
@@ -283,7 +284,7 @@ func addVMShellCommand(parent *cli.Command) {
 }
 
 func runVMShell(console bool, command []string) error {
-	d, err := devops.New()
+	d, err := devops.New(io.Local)
 	if err != nil {
 		return err
 	}
@@ -321,7 +322,7 @@ func addVMServeCommand(parent *cli.Command) {
 }
 
 func runVMServe(port int, path string) error {
-	d, err := devops.New()
+	d, err := devops.New(io.Local)
 	if err != nil {
 		return err
 	}
@@ -360,7 +361,7 @@ func addVMTestCommand(parent *cli.Command) {
 }
 
 func runVMTest(name string, command []string) error {
-	d, err := devops.New()
+	d, err := devops.New(io.Local)
 	if err != nil {
 		return err
 	}
@@ -405,7 +406,7 @@ func addVMClaudeCommand(parent *cli.Command) {
 }
 
 func runVMClaude(noAuth bool, model string, authFlags []string) error {
-	d, err := devops.New()
+	d, err := devops.New(io.Local)
 	if err != nil {
 		return err
 	}
@@ -445,7 +446,7 @@ func addVMUpdateCommand(parent *cli.Command) {
 }
 
 func runVMUpdate(apply bool) error {
-	d, err := devops.New()
+	d, err := devops.New(io.Local)
 	if err != nil {
 		return err
 	}
diff --git a/pkg/devops/config.go b/pkg/devops/config.go
index ab91790c..ee6a5178 100644
--- a/pkg/devops/config.go
+++ b/pkg/devops/config.go
@@ -62,15 +62,15 @@ func ConfigPath() (string, error) {
 	return filepath.Join(home, ".core", "config.yaml"), nil
 }
 
-// LoadConfig loads configuration from ~/.core/config.yaml.
+// LoadConfig loads configuration from ~/.core/config.yaml using the provided medium.
 // Returns default config if file doesn't exist.
-func LoadConfig() (*Config, error) {
+func LoadConfig(m io.Medium) (*Config, error) {
 	configPath, err := ConfigPath()
 	if err != nil {
 		return DefaultConfig(), nil
 	}
 
-	content, err := io.Local.Read(configPath)
+	content, err := m.Read(configPath)
 	if err != nil {
 		if os.IsNotExist(err) {
 			return DefaultConfig(), nil
diff --git a/pkg/devops/config_test.go b/pkg/devops/config_test.go
index cdd4ec7b..5ca5fa2b 100644
--- a/pkg/devops/config_test.go
+++ b/pkg/devops/config_test.go
@@ -5,6 +5,7 @@ import (
 	"path/filepath"
 	"testing"
 
+	"github.com/host-uk/core/pkg/io"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 )
@@ -30,7 +31,7 @@ func TestLoadConfig_Good(t *testing.T) {
 		t.Setenv("HOME", tempHome)
 		defer func() { _ = os.Setenv("HOME", origHome) }()
 
-		cfg, err := LoadConfig()
+		cfg, err := LoadConfig(io.Local)
 		assert.NoError(t, err)
 		assert.Equal(t, DefaultConfig(), cfg)
 	})
@@ -53,7 +54,7 @@ images:
 		err = os.WriteFile(filepath.Join(coreDir, "config.yaml"), []byte(configData), 0644)
 		require.NoError(t, err)
 
-		cfg, err := LoadConfig()
+		cfg, err := LoadConfig(io.Local)
 		assert.NoError(t, err)
 		assert.Equal(t, 2, cfg.Version)
 		assert.Equal(t, "cdn", cfg.Images.Source)
@@ -73,7 +74,7 @@ func TestLoadConfig_Bad(t *testing.T) {
 		err = os.WriteFile(filepath.Join(coreDir, "config.yaml"), []byte("invalid: yaml: :"), 0644)
 		require.NoError(t, err)
 
-		_, err = LoadConfig()
+		_, err = LoadConfig(io.Local)
 		assert.Error(t, err)
 	})
 }
@@ -127,7 +128,7 @@ images:
 	err = os.WriteFile(filepath.Join(coreDir, "config.yaml"), []byte(configData), 0644)
 	require.NoError(t, err)
 
-	cfg, err := LoadConfig()
+	cfg, err := LoadConfig(io.Local)
 	assert.NoError(t, err)
 	assert.Equal(t, 1, cfg.Version)
 	assert.Equal(t, "github", cfg.Images.Source)
@@ -197,7 +198,7 @@ images:
 			err = os.WriteFile(filepath.Join(coreDir, "config.yaml"), []byte(tt.config), 0644)
 			require.NoError(t, err)
 
-			cfg, err := LoadConfig()
+			cfg, err := LoadConfig(io.Local)
 			assert.NoError(t, err)
 			tt.check(t, cfg)
 		})
@@ -246,7 +247,7 @@ func TestLoadConfig_Bad_UnreadableFile(t *testing.T) {
 	err = os.WriteFile(configPath, []byte("version: 1"), 0000)
 	require.NoError(t, err)
 
-	_, err = LoadConfig()
+	_, err = LoadConfig(io.Local)
 	assert.Error(t, err)
 
 	// Restore permissions so cleanup works
diff --git a/pkg/devops/devops.go b/pkg/devops/devops.go
index 9b0491c4..39e87aec 100644
--- a/pkg/devops/devops.go
+++ b/pkg/devops/devops.go
@@ -15,19 +15,20 @@ import (
 
 // DevOps manages the portable development environment.
 type DevOps struct {
+	medium    io.Medium
 	config    *Config
 	images    *ImageManager
 	container *container.LinuxKitManager
 }
 
-// New creates a new DevOps instance.
-func New() (*DevOps, error) {
-	cfg, err := LoadConfig()
+// New creates a new DevOps instance using the provided medium.
+func New(m io.Medium) (*DevOps, error) {
+	cfg, err := LoadConfig(m)
 	if err != nil {
 		return nil, fmt.Errorf("devops.New: failed to load config: %w", err)
 	}
 
-	images, err := NewImageManager(cfg)
+	images, err := NewImageManager(m, cfg)
 	if err != nil {
 		return nil, fmt.Errorf("devops.New: failed to create image manager: %w", err)
 	}
@@ -38,6 +39,7 @@ func New() (*DevOps, error) {
 	}
 
 	return &DevOps{
+		medium:    m,
 		config:    cfg,
 		images:    images,
 		container: mgr,
@@ -76,7 +78,7 @@ func (d *DevOps) IsInstalled() bool {
 	if err != nil {
 		return false
 	}
-	return io.Local.IsFile(path)
+	return d.medium.IsFile(path)
 }
 
 // Install downloads and installs the dev image.
diff --git a/pkg/devops/devops_test.go b/pkg/devops/devops_test.go
index 4b75b8d0..fb28675b 100644
--- a/pkg/devops/devops_test.go
+++ b/pkg/devops/devops_test.go
@@ -10,6 +10,7 @@ import (
 	"time"
 
 	"github.com/host-uk/core/pkg/container"
+	"github.com/host-uk/core/pkg/io"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 )
@@ -69,7 +70,7 @@ func TestIsInstalled_Bad(t *testing.T) {
 		t.Setenv("CORE_IMAGES_DIR", tempDir)
 
 		// Create devops instance manually to avoid loading real config/images
-		d := &DevOps{}
+		d := &DevOps{medium: io.Local}
 		assert.False(t, d.IsInstalled())
 	})
 }
@@ -84,7 +85,7 @@ func TestIsInstalled_Good(t *testing.T) {
 		err := os.WriteFile(imagePath, []byte("fake image data"), 0644)
 		require.NoError(t, err)
 
-		d := &DevOps{}
+		d := &DevOps{medium: io.Local}
 		assert.True(t, d.IsInstalled())
 	})
 }
@@ -102,7 +103,7 @@ func TestDevOps_Status_Good(t *testing.T) {
 	t.Setenv("CORE_IMAGES_DIR", tempDir)
 
 	cfg := DefaultConfig()
-	mgr, err := NewImageManager(cfg)
+	mgr, err := NewImageManager(io.Local, cfg)
 	require.NoError(t, err)
 
 	// Setup mock container manager
@@ -111,7 +112,7 @@ func TestDevOps_Status_Good(t *testing.T) {
 	h := &mockHypervisor{}
 	cm := container.NewLinuxKitManagerWithHypervisor(state, h)
 
-	d := &DevOps{
+	d := &DevOps{medium: io.Local,
 		images:    mgr,
 		container: cm,
 	}
@@ -143,7 +144,7 @@ func TestDevOps_Status_Good_NotInstalled(t *testing.T) {
 	t.Setenv("CORE_IMAGES_DIR", tempDir)
 
 	cfg := DefaultConfig()
-	mgr, err := NewImageManager(cfg)
+	mgr, err := NewImageManager(io.Local, cfg)
 	require.NoError(t, err)
 
 	statePath := filepath.Join(tempDir, "containers.json")
@@ -151,7 +152,7 @@ func TestDevOps_Status_Good_NotInstalled(t *testing.T) {
 	h := &mockHypervisor{}
 	cm := container.NewLinuxKitManagerWithHypervisor(state, h)
 
-	d := &DevOps{
+	d := &DevOps{medium: io.Local,
 		images:    mgr,
 		container: cm,
 	}
@@ -174,7 +175,7 @@ func TestDevOps_Status_Good_NoContainer(t *testing.T) {
 	require.NoError(t, err)
 
 	cfg := DefaultConfig()
-	mgr, err := NewImageManager(cfg)
+	mgr, err := NewImageManager(io.Local, cfg)
 	require.NoError(t, err)
 
 	statePath := filepath.Join(tempDir, "containers.json")
@@ -182,7 +183,7 @@ func TestDevOps_Status_Good_NoContainer(t *testing.T) {
 	h := &mockHypervisor{}
 	cm := container.NewLinuxKitManagerWithHypervisor(state, h)
 
-	d := &DevOps{
+	d := &DevOps{medium: io.Local,
 		images:    mgr,
 		container: cm,
 	}
@@ -200,7 +201,7 @@ func TestDevOps_IsRunning_Good(t *testing.T) {
 	t.Setenv("CORE_IMAGES_DIR", tempDir)
 
 	cfg := DefaultConfig()
-	mgr, err := NewImageManager(cfg)
+	mgr, err := NewImageManager(io.Local, cfg)
 	require.NoError(t, err)
 
 	statePath := filepath.Join(tempDir, "containers.json")
@@ -208,7 +209,7 @@ func TestDevOps_IsRunning_Good(t *testing.T) {
 	h := &mockHypervisor{}
 	cm := container.NewLinuxKitManagerWithHypervisor(state, h)
 
-	d := &DevOps{
+	d := &DevOps{medium: io.Local,
 		images:    mgr,
 		container: cm,
 	}
@@ -233,7 +234,7 @@ func TestDevOps_IsRunning_Bad_NotRunning(t *testing.T) {
 	t.Setenv("CORE_IMAGES_DIR", tempDir)
 
 	cfg := DefaultConfig()
-	mgr, err := NewImageManager(cfg)
+	mgr, err := NewImageManager(io.Local, cfg)
 	require.NoError(t, err)
 
 	statePath := filepath.Join(tempDir, "containers.json")
@@ -241,7 +242,7 @@ func TestDevOps_IsRunning_Bad_NotRunning(t *testing.T) {
 	h := &mockHypervisor{}
 	cm := container.NewLinuxKitManagerWithHypervisor(state, h)
 
-	d := &DevOps{
+	d := &DevOps{medium: io.Local,
 		images:    mgr,
 		container: cm,
 	}
@@ -256,7 +257,7 @@ func TestDevOps_IsRunning_Bad_ContainerStopped(t *testing.T) {
 	t.Setenv("CORE_IMAGES_DIR", tempDir)
 
 	cfg := DefaultConfig()
-	mgr, err := NewImageManager(cfg)
+	mgr, err := NewImageManager(io.Local, cfg)
 	require.NoError(t, err)
 
 	statePath := filepath.Join(tempDir, "containers.json")
@@ -264,7 +265,7 @@ func TestDevOps_IsRunning_Bad_ContainerStopped(t *testing.T) {
 	h := &mockHypervisor{}
 	cm := container.NewLinuxKitManagerWithHypervisor(state, h)
 
-	d := &DevOps{
+	d := &DevOps{medium: io.Local,
 		images:    mgr,
 		container: cm,
 	}
@@ -289,7 +290,7 @@ func TestDevOps_findContainer_Good(t *testing.T) {
 	t.Setenv("CORE_IMAGES_DIR", tempDir)
 
 	cfg := DefaultConfig()
-	mgr, err := NewImageManager(cfg)
+	mgr, err := NewImageManager(io.Local, cfg)
 	require.NoError(t, err)
 
 	statePath := filepath.Join(tempDir, "containers.json")
@@ -297,7 +298,7 @@ func TestDevOps_findContainer_Good(t *testing.T) {
 	h := &mockHypervisor{}
 	cm := container.NewLinuxKitManagerWithHypervisor(state, h)
 
-	d := &DevOps{
+	d := &DevOps{medium: io.Local,
 		images:    mgr,
 		container: cm,
 	}
@@ -324,7 +325,7 @@ func TestDevOps_findContainer_Bad_NotFound(t *testing.T) {
 	t.Setenv("CORE_IMAGES_DIR", tempDir)
 
 	cfg := DefaultConfig()
-	mgr, err := NewImageManager(cfg)
+	mgr, err := NewImageManager(io.Local, cfg)
 	require.NoError(t, err)
 
 	statePath := filepath.Join(tempDir, "containers.json")
@@ -332,7 +333,7 @@ func TestDevOps_findContainer_Bad_NotFound(t *testing.T) {
 	h := &mockHypervisor{}
 	cm := container.NewLinuxKitManagerWithHypervisor(state, h)
 
-	d := &DevOps{
+	d := &DevOps{medium: io.Local,
 		images:    mgr,
 		container: cm,
 	}
@@ -347,7 +348,7 @@ func TestDevOps_Stop_Bad_NotFound(t *testing.T) {
 	t.Setenv("CORE_IMAGES_DIR", tempDir)
 
 	cfg := DefaultConfig()
-	mgr, err := NewImageManager(cfg)
+	mgr, err := NewImageManager(io.Local, cfg)
 	require.NoError(t, err)
 
 	statePath := filepath.Join(tempDir, "containers.json")
@@ -355,7 +356,7 @@ func TestDevOps_Stop_Bad_NotFound(t *testing.T) {
 	h := &mockHypervisor{}
 	cm := container.NewLinuxKitManagerWithHypervisor(state, h)
 
-	d := &DevOps{
+	d := &DevOps{medium: io.Local,
 		images:    mgr,
 		container: cm,
 	}
@@ -404,7 +405,7 @@ func TestDevOps_Boot_Bad_NotInstalled(t *testing.T) {
 	t.Setenv("CORE_IMAGES_DIR", tempDir)
 
 	cfg := DefaultConfig()
-	mgr, err := NewImageManager(cfg)
+	mgr, err := NewImageManager(io.Local, cfg)
 	require.NoError(t, err)
 
 	statePath := filepath.Join(tempDir, "containers.json")
@@ -412,7 +413,7 @@ func TestDevOps_Boot_Bad_NotInstalled(t *testing.T) {
 	h := &mockHypervisor{}
 	cm := container.NewLinuxKitManagerWithHypervisor(state, h)
 
-	d := &DevOps{
+	d := &DevOps{medium: io.Local,
 		images:    mgr,
 		container: cm,
 	}
@@ -432,7 +433,7 @@ func TestDevOps_Boot_Bad_AlreadyRunning(t *testing.T) {
 	require.NoError(t, err)
 
 	cfg := DefaultConfig()
-	mgr, err := NewImageManager(cfg)
+	mgr, err := NewImageManager(io.Local, cfg)
 	require.NoError(t, err)
 
 	statePath := filepath.Join(tempDir, "containers.json")
@@ -440,7 +441,7 @@ func TestDevOps_Boot_Bad_AlreadyRunning(t *testing.T) {
 	h := &mockHypervisor{}
 	cm := container.NewLinuxKitManagerWithHypervisor(state, h)
 
-	d := &DevOps{
+	d := &DevOps{medium: io.Local,
 		images:    mgr,
 		container: cm,
 	}
@@ -471,7 +472,7 @@ func TestDevOps_Status_Good_WithImageVersion(t *testing.T) {
 	require.NoError(t, err)
 
 	cfg := DefaultConfig()
-	mgr, err := NewImageManager(cfg)
+	mgr, err := NewImageManager(io.Local, cfg)
 	require.NoError(t, err)
 
 	// Manually set manifest with version info
@@ -485,7 +486,7 @@ func TestDevOps_Status_Good_WithImageVersion(t *testing.T) {
 	h := &mockHypervisor{}
 	cm := container.NewLinuxKitManagerWithHypervisor(state, h)
 
-	d := &DevOps{
+	d := &DevOps{medium: io.Local,
 		config:    cfg,
 		images:    mgr,
 		container: cm,
@@ -502,7 +503,7 @@ func TestDevOps_findContainer_Good_MultipleContainers(t *testing.T) {
 	t.Setenv("CORE_IMAGES_DIR", tempDir)
 
 	cfg := DefaultConfig()
-	mgr, err := NewImageManager(cfg)
+	mgr, err := NewImageManager(io.Local, cfg)
 	require.NoError(t, err)
 
 	statePath := filepath.Join(tempDir, "containers.json")
@@ -510,7 +511,7 @@ func TestDevOps_findContainer_Good_MultipleContainers(t *testing.T) {
 	h := &mockHypervisor{}
 	cm := container.NewLinuxKitManagerWithHypervisor(state, h)
 
-	d := &DevOps{
+	d := &DevOps{medium: io.Local,
 		images:    mgr,
 		container: cm,
 	}
@@ -547,7 +548,7 @@ func TestDevOps_Status_Good_ContainerWithUptime(t *testing.T) {
 	t.Setenv("CORE_IMAGES_DIR", tempDir)
 
 	cfg := DefaultConfig()
-	mgr, err := NewImageManager(cfg)
+	mgr, err := NewImageManager(io.Local, cfg)
 	require.NoError(t, err)
 
 	statePath := filepath.Join(tempDir, "containers.json")
@@ -555,7 +556,7 @@ func TestDevOps_Status_Good_ContainerWithUptime(t *testing.T) {
 	h := &mockHypervisor{}
 	cm := container.NewLinuxKitManagerWithHypervisor(state, h)
 
-	d := &DevOps{
+	d := &DevOps{medium: io.Local,
 		images:    mgr,
 		container: cm,
 	}
@@ -584,7 +585,7 @@ func TestDevOps_IsRunning_Bad_DifferentContainerName(t *testing.T) {
 	t.Setenv("CORE_IMAGES_DIR", tempDir)
 
 	cfg := DefaultConfig()
-	mgr, err := NewImageManager(cfg)
+	mgr, err := NewImageManager(io.Local, cfg)
 	require.NoError(t, err)
 
 	statePath := filepath.Join(tempDir, "containers.json")
@@ -592,7 +593,7 @@ func TestDevOps_IsRunning_Bad_DifferentContainerName(t *testing.T) {
 	h := &mockHypervisor{}
 	cm := container.NewLinuxKitManagerWithHypervisor(state, h)
 
-	d := &DevOps{
+	d := &DevOps{medium: io.Local,
 		images:    mgr,
 		container: cm,
 	}
@@ -626,7 +627,7 @@ func TestDevOps_Boot_Good_FreshFlag(t *testing.T) {
 	require.NoError(t, err)
 
 	cfg := DefaultConfig()
-	mgr, err := NewImageManager(cfg)
+	mgr, err := NewImageManager(io.Local, cfg)
 	require.NoError(t, err)
 
 	statePath := filepath.Join(tempDir, "containers.json")
@@ -634,7 +635,7 @@ func TestDevOps_Boot_Good_FreshFlag(t *testing.T) {
 	h := &mockHypervisor{}
 	cm := container.NewLinuxKitManagerWithHypervisor(state, h)
 
-	d := &DevOps{
+	d := &DevOps{medium: io.Local,
 		images:    mgr,
 		container: cm,
 	}
@@ -668,7 +669,7 @@ func TestDevOps_Stop_Bad_ContainerNotRunning(t *testing.T) {
 	t.Setenv("CORE_IMAGES_DIR", tempDir)
 
 	cfg := DefaultConfig()
-	mgr, err := NewImageManager(cfg)
+	mgr, err := NewImageManager(io.Local, cfg)
 	require.NoError(t, err)
 
 	statePath := filepath.Join(tempDir, "containers.json")
@@ -676,7 +677,7 @@ func TestDevOps_Stop_Bad_ContainerNotRunning(t *testing.T) {
 	h := &mockHypervisor{}
 	cm := container.NewLinuxKitManagerWithHypervisor(state, h)
 
-	d := &DevOps{
+	d := &DevOps{medium: io.Local,
 		images:    mgr,
 		container: cm,
 	}
@@ -710,7 +711,7 @@ func TestDevOps_Boot_Good_FreshWithNoExisting(t *testing.T) {
 	require.NoError(t, err)
 
 	cfg := DefaultConfig()
-	mgr, err := NewImageManager(cfg)
+	mgr, err := NewImageManager(io.Local, cfg)
 	require.NoError(t, err)
 
 	statePath := filepath.Join(tempDir, "containers.json")
@@ -718,7 +719,7 @@ func TestDevOps_Boot_Good_FreshWithNoExisting(t *testing.T) {
 	h := &mockHypervisor{}
 	cm := container.NewLinuxKitManagerWithHypervisor(state, h)
 
-	d := &DevOps{
+	d := &DevOps{medium: io.Local,
 		images:    mgr,
 		container: cm,
 	}
@@ -750,10 +751,10 @@ func TestDevOps_Install_Delegates(t *testing.T) {
 	t.Setenv("CORE_IMAGES_DIR", tempDir)
 
 	cfg := DefaultConfig()
-	mgr, err := NewImageManager(cfg)
+	mgr, err := NewImageManager(io.Local, cfg)
 	require.NoError(t, err)
 
-	d := &DevOps{
+	d := &DevOps{medium: io.Local,
 		images: mgr,
 	}
 
@@ -768,10 +769,10 @@ func TestDevOps_CheckUpdate_Delegates(t *testing.T) {
 	t.Setenv("CORE_IMAGES_DIR", tempDir)
 
 	cfg := DefaultConfig()
-	mgr, err := NewImageManager(cfg)
+	mgr, err := NewImageManager(io.Local, cfg)
 	require.NoError(t, err)
 
-	d := &DevOps{
+	d := &DevOps{medium: io.Local,
 		images: mgr,
 	}
 
@@ -792,7 +793,7 @@ func TestDevOps_Boot_Good_Success(t *testing.T) {
 	require.NoError(t, err)
 
 	cfg := DefaultConfig()
-	mgr, err := NewImageManager(cfg)
+	mgr, err := NewImageManager(io.Local, cfg)
 	require.NoError(t, err)
 
 	statePath := filepath.Join(tempDir, "containers.json")
@@ -800,7 +801,7 @@ func TestDevOps_Boot_Good_Success(t *testing.T) {
 	h := &mockHypervisor{}
 	cm := container.NewLinuxKitManagerWithHypervisor(state, h)
 
-	d := &DevOps{
+	d := &DevOps{medium: io.Local,
 		images:    mgr,
 		container: cm,
 	}
@@ -816,10 +817,10 @@ func TestDevOps_Config(t *testing.T) {
 	t.Setenv("CORE_IMAGES_DIR", tempDir)
 
 	cfg := DefaultConfig()
-	mgr, err := NewImageManager(cfg)
+	mgr, err := NewImageManager(io.Local, cfg)
 	require.NoError(t, err)
 
-	d := &DevOps{
+	d := &DevOps{medium: io.Local,
 		config: cfg,
 		images: mgr,
 	}
diff --git a/pkg/devops/images.go b/pkg/devops/images.go
index e6a93edc..7f2b5745 100644
--- a/pkg/devops/images.go
+++ b/pkg/devops/images.go
@@ -14,6 +14,7 @@ import (
 
 // ImageManager handles image downloads and updates.
 type ImageManager struct {
+	medium   io.Medium
 	config   *Config
 	manifest *Manifest
 	sources  []sources.ImageSource
@@ -21,6 +22,7 @@ type ImageManager struct {
 
 // Manifest tracks installed images.
 type Manifest struct {
+	medium io.Medium
 	Images map[string]ImageInfo `json:"images"`
 	path   string
 }
@@ -34,20 +36,20 @@ type ImageInfo struct {
 }
 
 // NewImageManager creates a new image manager.
-func NewImageManager(cfg *Config) (*ImageManager, error) {
+func NewImageManager(m io.Medium, cfg *Config) (*ImageManager, error) {
 	imagesDir, err := ImagesDir()
 	if err != nil {
 		return nil, err
 	}
 
 	// Ensure images directory exists
-	if err := io.Local.EnsureDir(imagesDir); err != nil {
+	if err := m.EnsureDir(imagesDir); err != nil {
 		return nil, err
 	}
 
 	// Load or create manifest
 	manifestPath := filepath.Join(imagesDir, "manifest.json")
-	manifest, err := loadManifest(manifestPath)
+	manifest, err := loadManifest(m, manifestPath)
 	if err != nil {
 		return nil, err
 	}
@@ -75,6 +77,7 @@ func NewImageManager(cfg *Config) (*ImageManager, error) {
 	}
 
 	return &ImageManager{
+		medium:   m,
 		config:   cfg,
 		manifest: manifest,
 		sources:  srcs,
@@ -87,7 +90,7 @@ func (m *ImageManager) IsInstalled() bool {
 	if err != nil {
 		return false
 	}
-	return io.Local.IsFile(path)
+	return m.medium.IsFile(path)
 }
 
 // Install downloads and installs the dev image.
@@ -118,7 +121,7 @@ func (m *ImageManager) Install(ctx context.Context, progress func(downloaded, to
 	fmt.Printf("Downloading %s from %s...\n", ImageName(), src.Name())
 
 	// Download
-	if err := src.Download(ctx, imagesDir, progress); err != nil {
+	if err := src.Download(ctx, m.medium, imagesDir, progress); err != nil {
 		return err
 	}
 
@@ -161,26 +164,28 @@ func (m *ImageManager) CheckUpdate(ctx context.Context) (current, latest string,
 	return current, latest, hasUpdate, nil
 }
 
-func loadManifest(path string) (*Manifest, error) {
-	m := &Manifest{
+func loadManifest(m io.Medium, path string) (*Manifest, error) {
+	manifest := &Manifest{
+		medium: m,
 		Images: make(map[string]ImageInfo),
 		path:   path,
 	}
 
-	content, err := io.Local.Read(path)
+	content, err := m.Read(path)
 	if err != nil {
 		if os.IsNotExist(err) {
-			return m, nil
+			return manifest, nil
 		}
 		return nil, err
 	}
 
-	if err := json.Unmarshal([]byte(content), m); err != nil {
+	if err := json.Unmarshal([]byte(content), manifest); err != nil {
 		return nil, err
 	}
-	m.path = path
+	manifest.medium = m
+	manifest.path = path
 
-	return m, nil
+	return manifest, nil
 }
 
 // Save writes the manifest to disk.
@@ -189,5 +194,5 @@ func (m *Manifest) Save() error {
 	if err != nil {
 		return err
 	}
-	return io.Local.Write(m.path, string(data))
+	return m.medium.Write(m.path, string(data))
 }
diff --git a/pkg/devops/images_test.go b/pkg/devops/images_test.go
index 8252efb5..72eeb3df 100644
--- a/pkg/devops/images_test.go
+++ b/pkg/devops/images_test.go
@@ -8,6 +8,7 @@ import (
 	"time"
 
 	"github.com/host-uk/core/pkg/devops/sources"
+	"github.com/host-uk/core/pkg/io"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 )
@@ -17,7 +18,7 @@ func TestImageManager_Good_IsInstalled(t *testing.T) {
 	t.Setenv("CORE_IMAGES_DIR", tmpDir)
 
 	cfg := DefaultConfig()
-	mgr, err := NewImageManager(cfg)
+	mgr, err := NewImageManager(io.Local, cfg)
 	require.NoError(t, err)
 
 	// Not installed yet
@@ -40,7 +41,7 @@ func TestNewImageManager_Good(t *testing.T) {
 		cfg := DefaultConfig()
 		cfg.Images.Source = "cdn"
 
-		mgr, err := NewImageManager(cfg)
+		mgr, err := NewImageManager(io.Local, cfg)
 		assert.NoError(t, err)
 		assert.NotNil(t, mgr)
 		assert.Len(t, mgr.sources, 1)
@@ -54,7 +55,7 @@ func TestNewImageManager_Good(t *testing.T) {
 		cfg := DefaultConfig()
 		cfg.Images.Source = "github"
 
-		mgr, err := NewImageManager(cfg)
+		mgr, err := NewImageManager(io.Local, cfg)
 		assert.NoError(t, err)
 		assert.NotNil(t, mgr)
 		assert.Len(t, mgr.sources, 1)
@@ -67,6 +68,7 @@ func TestManifest_Save(t *testing.T) {
 	path := filepath.Join(tmpDir, "manifest.json")
 
 	m := &Manifest{
+		medium: io.Local,
 		Images: make(map[string]ImageInfo),
 		path:   path,
 	}
@@ -84,7 +86,7 @@ func TestManifest_Save(t *testing.T) {
 	assert.NoError(t, err)
 
 	// Reload
-	m2, err := loadManifest(path)
+	m2, err := loadManifest(io.Local, path)
 	assert.NoError(t, err)
 	assert.Equal(t, "1.0.0", m2.Images["test.img"].Version)
 }
@@ -96,7 +98,7 @@ func TestLoadManifest_Bad(t *testing.T) {
 		err := os.WriteFile(path, []byte("invalid json"), 0644)
 		require.NoError(t, err)
 
-		_, err = loadManifest(path)
+		_, err = loadManifest(io.Local, path)
 		assert.Error(t, err)
 	})
 }
@@ -107,7 +109,7 @@ func TestCheckUpdate_Bad(t *testing.T) {
 		t.Setenv("CORE_IMAGES_DIR", tmpDir)
 
 		cfg := DefaultConfig()
-		mgr, err := NewImageManager(cfg)
+		mgr, err := NewImageManager(io.Local, cfg)
 		require.NoError(t, err)
 
 		_, _, _, err = mgr.CheckUpdate(context.Background())
@@ -123,7 +125,7 @@ func TestNewImageManager_Good_AutoSource(t *testing.T) {
 	cfg := DefaultConfig()
 	cfg.Images.Source = "auto"
 
-	mgr, err := NewImageManager(cfg)
+	mgr, err := NewImageManager(io.Local, cfg)
 	assert.NoError(t, err)
 	assert.NotNil(t, mgr)
 	assert.Len(t, mgr.sources, 2) // github and cdn
@@ -136,7 +138,7 @@ func TestNewImageManager_Good_UnknownSourceFallsToAuto(t *testing.T) {
 	cfg := DefaultConfig()
 	cfg.Images.Source = "unknown"
 
-	mgr, err := NewImageManager(cfg)
+	mgr, err := NewImageManager(io.Local, cfg)
 	assert.NoError(t, err)
 	assert.NotNil(t, mgr)
 	assert.Len(t, mgr.sources, 2) // falls to default (auto) which is github + cdn
@@ -146,7 +148,7 @@ func TestLoadManifest_Good_Empty(t *testing.T) {
 	tmpDir := t.TempDir()
 	path := filepath.Join(tmpDir, "nonexistent.json")
 
-	m, err := loadManifest(path)
+	m, err := loadManifest(io.Local, path)
 	assert.NoError(t, err)
 	assert.NotNil(t, m)
 	assert.NotNil(t, m.Images)
@@ -162,7 +164,7 @@ func TestLoadManifest_Good_ExistingData(t *testing.T) {
 	err := os.WriteFile(path, []byte(data), 0644)
 	require.NoError(t, err)
 
-	m, err := loadManifest(path)
+	m, err := loadManifest(io.Local, path)
 	assert.NoError(t, err)
 	assert.NotNil(t, m)
 	assert.Equal(t, "2.0.0", m.Images["test.img"].Version)
@@ -187,6 +189,7 @@ func TestManifest_Save_Good_CreatesDirs(t *testing.T) {
 	nestedPath := filepath.Join(tmpDir, "nested", "dir", "manifest.json")
 
 	m := &Manifest{
+		medium: io.Local,
 		Images: make(map[string]ImageInfo),
 		path:   nestedPath,
 	}
@@ -207,6 +210,7 @@ func TestManifest_Save_Good_Overwrite(t *testing.T) {
 
 	// First save
 	m1 := &Manifest{
+		medium: io.Local,
 		Images: make(map[string]ImageInfo),
 		path:   path,
 	}
@@ -216,6 +220,7 @@ func TestManifest_Save_Good_Overwrite(t *testing.T) {
 
 	// Second save with different data
 	m2 := &Manifest{
+		medium: io.Local,
 		Images: make(map[string]ImageInfo),
 		path:   path,
 	}
@@ -224,7 +229,7 @@ func TestManifest_Save_Good_Overwrite(t *testing.T) {
 	require.NoError(t, err)
 
 	// Verify second data
-	loaded, err := loadManifest(path)
+	loaded, err := loadManifest(io.Local, path)
 	assert.NoError(t, err)
 	assert.Equal(t, "2.0.0", loaded.Images["other.img"].Version)
 	_, exists := loaded.Images["test.img"]
@@ -237,8 +242,9 @@ func TestImageManager_Install_Bad_NoSourceAvailable(t *testing.T) {
 
 	// Create manager with empty sources
 	mgr := &ImageManager{
+		medium:   io.Local,
 		config:   DefaultConfig(),
-		manifest: &Manifest{Images: make(map[string]ImageInfo), path: filepath.Join(tmpDir, "manifest.json")},
+		manifest: &Manifest{medium: io.Local, Images: make(map[string]ImageInfo), path: filepath.Join(tmpDir, "manifest.json")},
 		sources:  nil, // no sources
 	}
 
@@ -253,7 +259,7 @@ func TestNewImageManager_Good_CreatesDir(t *testing.T) {
 	t.Setenv("CORE_IMAGES_DIR", imagesDir)
 
 	cfg := DefaultConfig()
-	mgr, err := NewImageManager(cfg)
+	mgr, err := NewImageManager(io.Local, cfg)
 	assert.NoError(t, err)
 	assert.NotNil(t, mgr)
 
@@ -277,7 +283,7 @@ func (m *mockImageSource) Available() bool { return m.available }
 func (m *mockImageSource) LatestVersion(ctx context.Context) (string, error) {
 	return m.latestVersion, m.latestErr
 }
-func (m *mockImageSource) Download(ctx context.Context, dest string, progress func(downloaded, total int64)) error {
+func (m *mockImageSource) Download(ctx context.Context, medium io.Medium, dest string, progress func(downloaded, total int64)) error {
 	if m.downloadErr != nil {
 		return m.downloadErr
 	}
@@ -297,8 +303,9 @@ func TestImageManager_Install_Good_WithMockSource(t *testing.T) {
 	}
 
 	mgr := &ImageManager{
+		medium:   io.Local,
 		config:   DefaultConfig(),
-		manifest: &Manifest{Images: make(map[string]ImageInfo), path: filepath.Join(tmpDir, "manifest.json")},
+		manifest: &Manifest{medium: io.Local, Images: make(map[string]ImageInfo), path: filepath.Join(tmpDir, "manifest.json")},
 		sources:  []sources.ImageSource{mock},
 	}
 
@@ -325,8 +332,9 @@ func TestImageManager_Install_Bad_DownloadError(t *testing.T) {
 	}
 
 	mgr := &ImageManager{
+		medium:   io.Local,
 		config:   DefaultConfig(),
-		manifest: &Manifest{Images: make(map[string]ImageInfo), path: filepath.Join(tmpDir, "manifest.json")},
+		manifest: &Manifest{medium: io.Local, Images: make(map[string]ImageInfo), path: filepath.Join(tmpDir, "manifest.json")},
 		sources:  []sources.ImageSource{mock},
 	}
 
@@ -345,8 +353,9 @@ func TestImageManager_Install_Bad_VersionError(t *testing.T) {
 	}
 
 	mgr := &ImageManager{
+		medium:   io.Local,
 		config:   DefaultConfig(),
-		manifest: &Manifest{Images: make(map[string]ImageInfo), path: filepath.Join(tmpDir, "manifest.json")},
+		manifest: &Manifest{medium: io.Local, Images: make(map[string]ImageInfo), path: filepath.Join(tmpDir, "manifest.json")},
 		sources:  []sources.ImageSource{mock},
 	}
 
@@ -370,8 +379,9 @@ func TestImageManager_Install_Good_SkipsUnavailableSource(t *testing.T) {
 	}
 
 	mgr := &ImageManager{
+		medium:   io.Local,
 		config:   DefaultConfig(),
-		manifest: &Manifest{Images: make(map[string]ImageInfo), path: filepath.Join(tmpDir, "manifest.json")},
+		manifest: &Manifest{medium: io.Local, Images: make(map[string]ImageInfo), path: filepath.Join(tmpDir, "manifest.json")},
 		sources:  []sources.ImageSource{unavailableMock, availableMock},
 	}
 
@@ -394,8 +404,10 @@ func TestImageManager_CheckUpdate_Good_WithMockSource(t *testing.T) {
 	}
 
 	mgr := &ImageManager{
+		medium: io.Local,
 		config: DefaultConfig(),
 		manifest: &Manifest{
+			medium: io.Local,
 			Images: map[string]ImageInfo{
 				ImageName(): {Version: "v1.0.0", Source: "mock"},
 			},
@@ -422,8 +434,10 @@ func TestImageManager_CheckUpdate_Good_NoUpdate(t *testing.T) {
 	}
 
 	mgr := &ImageManager{
+		medium: io.Local,
 		config: DefaultConfig(),
 		manifest: &Manifest{
+			medium: io.Local,
 			Images: map[string]ImageInfo{
 				ImageName(): {Version: "v1.0.0", Source: "mock"},
 			},
@@ -449,8 +463,10 @@ func TestImageManager_CheckUpdate_Bad_NoSource(t *testing.T) {
 	}
 
 	mgr := &ImageManager{
+		medium: io.Local,
 		config: DefaultConfig(),
 		manifest: &Manifest{
+			medium: io.Local,
 			Images: map[string]ImageInfo{
 				ImageName(): {Version: "v1.0.0", Source: "mock"},
 			},
@@ -475,8 +491,10 @@ func TestImageManager_CheckUpdate_Bad_VersionError(t *testing.T) {
 	}
 
 	mgr := &ImageManager{
+		medium: io.Local,
 		config: DefaultConfig(),
 		manifest: &Manifest{
+			medium: io.Local,
 			Images: map[string]ImageInfo{
 				ImageName(): {Version: "v1.0.0", Source: "mock"},
 			},
@@ -495,8 +513,9 @@ func TestImageManager_Install_Bad_EmptySources(t *testing.T) {
 	t.Setenv("CORE_IMAGES_DIR", tmpDir)
 
 	mgr := &ImageManager{
+		medium:   io.Local,
 		config:   DefaultConfig(),
-		manifest: &Manifest{Images: make(map[string]ImageInfo), path: filepath.Join(tmpDir, "manifest.json")},
+		manifest: &Manifest{medium: io.Local, Images: make(map[string]ImageInfo), path: filepath.Join(tmpDir, "manifest.json")},
 		sources:  []sources.ImageSource{}, // Empty slice, not nil
 	}
 
@@ -513,8 +532,9 @@ func TestImageManager_Install_Bad_AllUnavailable(t *testing.T) {
 	mock2 := &mockImageSource{name: "mock2", available: false}
 
 	mgr := &ImageManager{
+		medium:   io.Local,
 		config:   DefaultConfig(),
-		manifest: &Manifest{Images: make(map[string]ImageInfo), path: filepath.Join(tmpDir, "manifest.json")},
+		manifest: &Manifest{medium: io.Local, Images: make(map[string]ImageInfo), path: filepath.Join(tmpDir, "manifest.json")},
 		sources:  []sources.ImageSource{mock1, mock2},
 	}
 
@@ -531,8 +551,10 @@ func TestImageManager_CheckUpdate_Good_FirstSourceUnavailable(t *testing.T) {
 	available := &mockImageSource{name: "available", available: true, latestVersion: "v2.0.0"}
 
 	mgr := &ImageManager{
+		medium: io.Local,
 		config: DefaultConfig(),
 		manifest: &Manifest{
+			medium: io.Local,
 			Images: map[string]ImageInfo{
 				ImageName(): {Version: "v1.0.0", Source: "available"},
 			},
diff --git a/pkg/devops/serve.go b/pkg/devops/serve.go
index 78f784b1..1e0dc802 100644
--- a/pkg/devops/serve.go
+++ b/pkg/devops/serve.go
@@ -6,6 +6,8 @@ import (
 	"os"
 	"os/exec"
 	"path/filepath"
+
+	"github.com/host-uk/core/pkg/io"
 )
 
 // ServeOptions configures the dev server.
@@ -39,7 +41,7 @@ func (d *DevOps) Serve(ctx context.Context, projectDir string, opts ServeOptions
 	}
 
 	// Detect and run serve command
-	serveCmd := DetectServeCommand(servePath)
+	serveCmd := DetectServeCommand(d.medium, servePath)
 	fmt.Printf("Starting server: %s\n", serveCmd)
 	fmt.Printf("Listening on http://localhost:%d\n", opts.Port)
 
@@ -69,36 +71,36 @@ func (d *DevOps) mountProject(ctx context.Context, path string) error {
 }
 
 // DetectServeCommand auto-detects the serve command for a project.
-func DetectServeCommand(projectDir string) string {
+func DetectServeCommand(m io.Medium, projectDir string) string {
 	// Laravel/Octane
-	if hasFile(projectDir, "artisan") {
+	if hasFile(m, projectDir, "artisan") {
 		return "php artisan octane:start --host=0.0.0.0 --port=8000"
 	}
 
 	// Node.js with dev script
-	if hasFile(projectDir, "package.json") {
-		if hasPackageScript(projectDir, "dev") {
+	if hasFile(m, projectDir, "package.json") {
+		if hasPackageScript(m, projectDir, "dev") {
 			return "npm run dev -- --host 0.0.0.0"
 		}
-		if hasPackageScript(projectDir, "start") {
+		if hasPackageScript(m, projectDir, "start") {
 			return "npm start"
 		}
 	}
 
 	// PHP with composer
-	if hasFile(projectDir, "composer.json") {
+	if hasFile(m, projectDir, "composer.json") {
 		return "frankenphp php-server -l :8000"
 	}
 
 	// Go
-	if hasFile(projectDir, "go.mod") {
-		if hasFile(projectDir, "main.go") {
+	if hasFile(m, projectDir, "go.mod") {
+		if hasFile(m, projectDir, "main.go") {
 			return "go run ."
 		}
 	}
 
 	// Python Django
-	if hasFile(projectDir, "manage.py") {
+	if hasFile(m, projectDir, "manage.py") {
 		return "python manage.py runserver 0.0.0.0:8000"
 	}
 
diff --git a/pkg/devops/serve_test.go b/pkg/devops/serve_test.go
index 54e1949f..57dc8362 100644
--- a/pkg/devops/serve_test.go
+++ b/pkg/devops/serve_test.go
@@ -5,6 +5,7 @@ import (
 	"path/filepath"
 	"testing"
 
+	"github.com/host-uk/core/pkg/io"
 	"github.com/stretchr/testify/assert"
 )
 
@@ -13,7 +14,7 @@ func TestDetectServeCommand_Good_Laravel(t *testing.T) {
 	err := os.WriteFile(filepath.Join(tmpDir, "artisan"), []byte("#!/usr/bin/env php"), 0644)
 	assert.NoError(t, err)
 
-	cmd := DetectServeCommand(tmpDir)
+	cmd := DetectServeCommand(io.Local, tmpDir)
 	assert.Equal(t, "php artisan octane:start --host=0.0.0.0 --port=8000", cmd)
 }
 
@@ -23,7 +24,7 @@ func TestDetectServeCommand_Good_NodeDev(t *testing.T) {
 	err := os.WriteFile(filepath.Join(tmpDir, "package.json"), []byte(packageJSON), 0644)
 	assert.NoError(t, err)
 
-	cmd := DetectServeCommand(tmpDir)
+	cmd := DetectServeCommand(io.Local, tmpDir)
 	assert.Equal(t, "npm run dev -- --host 0.0.0.0", cmd)
 }
 
@@ -33,7 +34,7 @@ func TestDetectServeCommand_Good_NodeStart(t *testing.T) {
 	err := os.WriteFile(filepath.Join(tmpDir, "package.json"), []byte(packageJSON), 0644)
 	assert.NoError(t, err)
 
-	cmd := DetectServeCommand(tmpDir)
+	cmd := DetectServeCommand(io.Local, tmpDir)
 	assert.Equal(t, "npm start", cmd)
 }
 
@@ -42,7 +43,7 @@ func TestDetectServeCommand_Good_PHP(t *testing.T) {
 	err := os.WriteFile(filepath.Join(tmpDir, "composer.json"), []byte(`{"require":{}}`), 0644)
 	assert.NoError(t, err)
 
-	cmd := DetectServeCommand(tmpDir)
+	cmd := DetectServeCommand(io.Local, tmpDir)
 	assert.Equal(t, "frankenphp php-server -l :8000", cmd)
 }
 
@@ -53,7 +54,7 @@ func TestDetectServeCommand_Good_GoMain(t *testing.T) {
 	err = os.WriteFile(filepath.Join(tmpDir, "main.go"), []byte("package main"), 0644)
 	assert.NoError(t, err)
 
-	cmd := DetectServeCommand(tmpDir)
+	cmd := DetectServeCommand(io.Local, tmpDir)
 	assert.Equal(t, "go run .", cmd)
 }
 
@@ -63,7 +64,7 @@ func TestDetectServeCommand_Good_GoWithoutMain(t *testing.T) {
 	assert.NoError(t, err)
 
 	// No main.go, so falls through to fallback
-	cmd := DetectServeCommand(tmpDir)
+	cmd := DetectServeCommand(io.Local, tmpDir)
 	assert.Equal(t, "python3 -m http.server 8000", cmd)
 }
 
@@ -72,14 +73,14 @@ func TestDetectServeCommand_Good_Django(t *testing.T) {
 	err := os.WriteFile(filepath.Join(tmpDir, "manage.py"), []byte("#!/usr/bin/env python"), 0644)
 	assert.NoError(t, err)
 
-	cmd := DetectServeCommand(tmpDir)
+	cmd := DetectServeCommand(io.Local, tmpDir)
 	assert.Equal(t, "python manage.py runserver 0.0.0.0:8000", cmd)
 }
 
 func TestDetectServeCommand_Good_Fallback(t *testing.T) {
 	tmpDir := t.TempDir()
 
-	cmd := DetectServeCommand(tmpDir)
+	cmd := DetectServeCommand(io.Local, tmpDir)
 	assert.Equal(t, "python3 -m http.server 8000", cmd)
 }
 
@@ -91,7 +92,7 @@ func TestDetectServeCommand_Good_Priority(t *testing.T) {
 	err = os.WriteFile(filepath.Join(tmpDir, "composer.json"), []byte(`{"require":{}}`), 0644)
 	assert.NoError(t, err)
 
-	cmd := DetectServeCommand(tmpDir)
+	cmd := DetectServeCommand(io.Local, tmpDir)
 	assert.Equal(t, "php artisan octane:start --host=0.0.0.0 --port=8000", cmd)
 }
 
@@ -116,13 +117,13 @@ func TestHasFile_Good(t *testing.T) {
 	err := os.WriteFile(testFile, []byte("content"), 0644)
 	assert.NoError(t, err)
 
-	assert.True(t, hasFile(tmpDir, "test.txt"))
+	assert.True(t, hasFile(io.Local, tmpDir, "test.txt"))
 }
 
 func TestHasFile_Bad(t *testing.T) {
 	tmpDir := t.TempDir()
 
-	assert.False(t, hasFile(tmpDir, "nonexistent.txt"))
+	assert.False(t, hasFile(io.Local, tmpDir, "nonexistent.txt"))
 }
 
 func TestHasFile_Bad_Directory(t *testing.T) {
@@ -132,5 +133,5 @@ func TestHasFile_Bad_Directory(t *testing.T) {
 	assert.NoError(t, err)
 
 	// hasFile correctly returns false for directories (only true for regular files)
-	assert.False(t, hasFile(tmpDir, "subdir"))
+	assert.False(t, hasFile(io.Local, tmpDir, "subdir"))
 }
diff --git a/pkg/devops/sources/cdn.go b/pkg/devops/sources/cdn.go
index 41269624..8408cf88 100644
--- a/pkg/devops/sources/cdn.go
+++ b/pkg/devops/sources/cdn.go
@@ -54,7 +54,7 @@ func (s *CDNSource) LatestVersion(ctx context.Context) (string, error) {
 }
 
 // Download downloads the image from CDN.
-func (s *CDNSource) Download(ctx context.Context, dest string, progress func(downloaded, total int64)) error {
+func (s *CDNSource) Download(ctx context.Context, m io.Medium, dest string, progress func(downloaded, total int64)) error {
 	url := fmt.Sprintf("%s/%s", s.config.CDNURL, s.config.ImageName)
 
 	req, err := http.NewRequestWithContext(ctx, "GET", url, nil)
@@ -73,7 +73,7 @@ func (s *CDNSource) Download(ctx context.Context, dest string, progress func(dow
 	}
 
 	// Ensure dest directory exists
-	if err := io.Local.EnsureDir(dest); err != nil {
+	if err := m.EnsureDir(dest); err != nil {
 		return fmt.Errorf("cdn.Download: %w", err)
 	}
 
diff --git a/pkg/devops/sources/cdn_test.go b/pkg/devops/sources/cdn_test.go
index de9c9639..2fe33c85 100644
--- a/pkg/devops/sources/cdn_test.go
+++ b/pkg/devops/sources/cdn_test.go
@@ -9,6 +9,7 @@ import (
 	"path/filepath"
 	"testing"
 
+	"github.com/host-uk/core/pkg/io"
 	"github.com/stretchr/testify/assert"
 )
 
@@ -71,7 +72,7 @@ func TestCDNSource_Download_Good(t *testing.T) {
 	})
 
 	var progressCalled bool
-	err := src.Download(context.Background(), dest, func(downloaded, total int64) {
+	err := src.Download(context.Background(), io.Local, dest, func(downloaded, total int64) {
 		progressCalled = true
 	})
 
@@ -97,7 +98,7 @@ func TestCDNSource_Download_Bad(t *testing.T) {
 			ImageName: "test.img",
 		})
 
-		err := src.Download(context.Background(), dest, nil)
+		err := src.Download(context.Background(), io.Local, dest, nil)
 		assert.Error(t, err)
 		assert.Contains(t, err.Error(), "HTTP 500")
 	})
@@ -109,7 +110,7 @@ func TestCDNSource_Download_Bad(t *testing.T) {
 			ImageName: "test.img",
 		})
 
-		err := src.Download(context.Background(), dest, nil)
+		err := src.Download(context.Background(), io.Local, dest, nil)
 		assert.Error(t, err)
 	})
 }
@@ -162,7 +163,7 @@ func TestCDNSource_Download_Good_NoProgress(t *testing.T) {
 	})
 
 	// nil progress callback should be handled gracefully
-	err := src.Download(context.Background(), dest, nil)
+	err := src.Download(context.Background(), io.Local, dest, nil)
 	assert.NoError(t, err)
 
 	data, err := os.ReadFile(filepath.Join(dest, "test.img"))
@@ -192,7 +193,7 @@ func TestCDNSource_Download_Good_LargeFile(t *testing.T) {
 
 	var progressCalls int
 	var lastDownloaded int64
-	err := src.Download(context.Background(), dest, func(downloaded, total int64) {
+	err := src.Download(context.Background(), io.Local, dest, func(downloaded, total int64) {
 		progressCalls++
 		lastDownloaded = downloaded
 	})
@@ -227,7 +228,7 @@ func TestCDNSource_Download_Bad_HTTPErrorCodes(t *testing.T) {
 				ImageName: "test.img",
 			})
 
-			err := src.Download(context.Background(), dest, nil)
+			err := src.Download(context.Background(), io.Local, dest, nil)
 			assert.Error(t, err)
 			assert.Contains(t, err.Error(), fmt.Sprintf("HTTP %d", tc.statusCode))
 		})
@@ -281,7 +282,7 @@ func TestCDNSource_Download_Good_CreatesDestDir(t *testing.T) {
 		ImageName: "test.img",
 	})
 
-	err := src.Download(context.Background(), dest, nil)
+	err := src.Download(context.Background(), io.Local, dest, nil)
 	assert.NoError(t, err)
 
 	// Verify nested dir was created
diff --git a/pkg/devops/sources/github.go b/pkg/devops/sources/github.go
index 98a86b67..323f2dda 100644
--- a/pkg/devops/sources/github.go
+++ b/pkg/devops/sources/github.go
@@ -6,6 +6,8 @@ import (
 	"os"
 	"os/exec"
 	"strings"
+
+	"github.com/host-uk/core/pkg/io"
 )
 
 // GitHubSource downloads images from GitHub Releases.
@@ -52,7 +54,7 @@ func (s *GitHubSource) LatestVersion(ctx context.Context) (string, error) {
 }
 
 // Download downloads the image from the latest release.
-func (s *GitHubSource) Download(ctx context.Context, dest string, progress func(downloaded, total int64)) error {
+func (s *GitHubSource) Download(ctx context.Context, m io.Medium, dest string, progress func(downloaded, total int64)) error {
 	// Get release assets to find our image
 	cmd := exec.CommandContext(ctx, "gh", "release", "download",
 		"-R", s.config.GitHubRepo,
diff --git a/pkg/devops/sources/source.go b/pkg/devops/sources/source.go
index 94e4ff68..f5ca4460 100644
--- a/pkg/devops/sources/source.go
+++ b/pkg/devops/sources/source.go
@@ -3,6 +3,8 @@ package sources
 
 import (
 	"context"
+
+	"github.com/host-uk/core/pkg/io"
 )
 
 // ImageSource defines the interface for downloading dev images.
@@ -15,7 +17,7 @@ type ImageSource interface {
 	LatestVersion(ctx context.Context) (string, error)
 	// Download downloads the image to the destination path.
 	// Reports progress via the callback if provided.
-	Download(ctx context.Context, dest string, progress func(downloaded, total int64)) error
+	Download(ctx context.Context, m io.Medium, dest string, progress func(downloaded, total int64)) error
 }
 
 // SourceConfig holds configuration for a source.
diff --git a/pkg/devops/test.go b/pkg/devops/test.go
index e424472e..89d1726c 100644
--- a/pkg/devops/test.go
+++ b/pkg/devops/test.go
@@ -47,7 +47,7 @@ func (d *DevOps) Test(ctx context.Context, projectDir string, opts TestOptions)
 	if len(opts.Command) > 0 {
 		cmd = strings.Join(opts.Command, " ")
 	} else if opts.Name != "" {
-		cfg, err := LoadTestConfig(projectDir)
+		cfg, err := LoadTestConfig(d.medium, projectDir)
 		if err != nil {
 			return err
 		}
@@ -61,7 +61,7 @@ func (d *DevOps) Test(ctx context.Context, projectDir string, opts TestOptions)
 			return fmt.Errorf("test command %q not found in .core/test.yaml", opts.Name)
 		}
 	} else {
-		cmd = DetectTestCommand(projectDir)
+		cmd = DetectTestCommand(d.medium, projectDir)
 		if cmd == "" {
 			return fmt.Errorf("could not detect test command (create .core/test.yaml)")
 		}
@@ -72,39 +72,39 @@ func (d *DevOps) Test(ctx context.Context, projectDir string, opts TestOptions)
 }
 
 // DetectTestCommand auto-detects the test command for a project.
-func DetectTestCommand(projectDir string) string {
+func DetectTestCommand(m io.Medium, projectDir string) string {
 	// 1. Check .core/test.yaml
-	cfg, err := LoadTestConfig(projectDir)
+	cfg, err := LoadTestConfig(m, projectDir)
 	if err == nil && cfg.Command != "" {
 		return cfg.Command
 	}
 
 	// 2. Check composer.json for test script
-	if hasFile(projectDir, "composer.json") {
-		if hasComposerScript(projectDir, "test") {
+	if hasFile(m, projectDir, "composer.json") {
+		if hasComposerScript(m, projectDir, "test") {
 			return "composer test"
 		}
 	}
 
 	// 3. Check package.json for test script
-	if hasFile(projectDir, "package.json") {
-		if hasPackageScript(projectDir, "test") {
+	if hasFile(m, projectDir, "package.json") {
+		if hasPackageScript(m, projectDir, "test") {
 			return "npm test"
 		}
 	}
 
 	// 4. Check go.mod
-	if hasFile(projectDir, "go.mod") {
+	if hasFile(m, projectDir, "go.mod") {
 		return "go test ./..."
 	}
 
 	// 5. Check pytest
-	if hasFile(projectDir, "pytest.ini") || hasFile(projectDir, "pyproject.toml") {
+	if hasFile(m, projectDir, "pytest.ini") || hasFile(m, projectDir, "pyproject.toml") {
 		return "pytest"
 	}
 
 	// 6. Check Taskfile
-	if hasFile(projectDir, "Taskfile.yaml") || hasFile(projectDir, "Taskfile.yml") {
+	if hasFile(m, projectDir, "Taskfile.yaml") || hasFile(m, projectDir, "Taskfile.yml") {
 		return "task test"
 	}
 
@@ -112,14 +112,14 @@ func DetectTestCommand(projectDir string) string {
 }
 
 // LoadTestConfig loads .core/test.yaml.
-func LoadTestConfig(projectDir string) (*TestConfig, error) {
+func LoadTestConfig(m io.Medium, projectDir string) (*TestConfig, error) {
 	path := filepath.Join(projectDir, ".core", "test.yaml")
 	absPath, err := filepath.Abs(path)
 	if err != nil {
 		return nil, err
 	}
 
-	content, err := io.Local.Read(absPath)
+	content, err := m.Read(absPath)
 	if err != nil {
 		return nil, err
 	}
@@ -132,23 +132,23 @@ func LoadTestConfig(projectDir string) (*TestConfig, error) {
 	return &cfg, nil
 }
 
-func hasFile(dir, name string) bool {
+func hasFile(m io.Medium, dir, name string) bool {
 	path := filepath.Join(dir, name)
 	absPath, err := filepath.Abs(path)
 	if err != nil {
 		return false
 	}
-	return io.Local.IsFile(absPath)
+	return m.IsFile(absPath)
 }
 
-func hasPackageScript(projectDir, script string) bool {
+func hasPackageScript(m io.Medium, projectDir, script string) bool {
 	path := filepath.Join(projectDir, "package.json")
 	absPath, err := filepath.Abs(path)
 	if err != nil {
 		return false
 	}
 
-	content, err := io.Local.Read(absPath)
+	content, err := m.Read(absPath)
 	if err != nil {
 		return false
 	}
@@ -164,14 +164,14 @@ func hasPackageScript(projectDir, script string) bool {
 	return ok
 }
 
-func hasComposerScript(projectDir, script string) bool {
+func hasComposerScript(m io.Medium, projectDir, script string) bool {
 	path := filepath.Join(projectDir, "composer.json")
 	absPath, err := filepath.Abs(path)
 	if err != nil {
 		return false
 	}
 
-	content, err := io.Local.Read(absPath)
+	content, err := m.Read(absPath)
 	if err != nil {
 		return false
 	}
diff --git a/pkg/devops/test_test.go b/pkg/devops/test_test.go
index 2a20e6e2..8f4cff77 100644
--- a/pkg/devops/test_test.go
+++ b/pkg/devops/test_test.go
@@ -4,13 +4,15 @@ import (
 	"os"
 	"path/filepath"
 	"testing"
+
+	"github.com/host-uk/core/pkg/io"
 )
 
 func TestDetectTestCommand_Good_ComposerJSON(t *testing.T) {
 	tmpDir := t.TempDir()
 	_ = os.WriteFile(filepath.Join(tmpDir, "composer.json"), []byte(`{"scripts":{"test":"pest"}}`), 0644)
 
-	cmd := DetectTestCommand(tmpDir)
+	cmd := DetectTestCommand(io.Local, tmpDir)
 	if cmd != "composer test" {
 		t.Errorf("expected 'composer test', got %q", cmd)
 	}
@@ -20,7 +22,7 @@ func TestDetectTestCommand_Good_PackageJSON(t *testing.T) {
 	tmpDir := t.TempDir()
 	_ = os.WriteFile(filepath.Join(tmpDir, "package.json"), []byte(`{"scripts":{"test":"vitest"}}`), 0644)
 
-	cmd := DetectTestCommand(tmpDir)
+	cmd := DetectTestCommand(io.Local, tmpDir)
 	if cmd != "npm test" {
 		t.Errorf("expected 'npm test', got %q", cmd)
 	}
@@ -30,7 +32,7 @@ func TestDetectTestCommand_Good_GoMod(t *testing.T) {
 	tmpDir := t.TempDir()
 	_ = os.WriteFile(filepath.Join(tmpDir, "go.mod"), []byte("module example"), 0644)
 
-	cmd := DetectTestCommand(tmpDir)
+	cmd := DetectTestCommand(io.Local, tmpDir)
 	if cmd != "go test ./..." {
 		t.Errorf("expected 'go test ./...', got %q", cmd)
 	}
@@ -42,7 +44,7 @@ func TestDetectTestCommand_Good_CoreTestYaml(t *testing.T) {
 	_ = os.MkdirAll(coreDir, 0755)
 	_ = os.WriteFile(filepath.Join(coreDir, "test.yaml"), []byte("command: custom-test"), 0644)
 
-	cmd := DetectTestCommand(tmpDir)
+	cmd := DetectTestCommand(io.Local, tmpDir)
 	if cmd != "custom-test" {
 		t.Errorf("expected 'custom-test', got %q", cmd)
 	}
@@ -52,7 +54,7 @@ func TestDetectTestCommand_Good_Pytest(t *testing.T) {
 	tmpDir := t.TempDir()
 	_ = os.WriteFile(filepath.Join(tmpDir, "pytest.ini"), []byte("[pytest]"), 0644)
 
-	cmd := DetectTestCommand(tmpDir)
+	cmd := DetectTestCommand(io.Local, tmpDir)
 	if cmd != "pytest" {
 		t.Errorf("expected 'pytest', got %q", cmd)
 	}
@@ -62,7 +64,7 @@ func TestDetectTestCommand_Good_Taskfile(t *testing.T) {
 	tmpDir := t.TempDir()
 	_ = os.WriteFile(filepath.Join(tmpDir, "Taskfile.yaml"), []byte("version: '3'"), 0644)
 
-	cmd := DetectTestCommand(tmpDir)
+	cmd := DetectTestCommand(io.Local, tmpDir)
 	if cmd != "task test" {
 		t.Errorf("expected 'task test', got %q", cmd)
 	}
@@ -71,7 +73,7 @@ func TestDetectTestCommand_Good_Taskfile(t *testing.T) {
 func TestDetectTestCommand_Bad_NoFiles(t *testing.T) {
 	tmpDir := t.TempDir()
 
-	cmd := DetectTestCommand(tmpDir)
+	cmd := DetectTestCommand(io.Local, tmpDir)
 	if cmd != "" {
 		t.Errorf("expected empty string, got %q", cmd)
 	}
@@ -85,7 +87,7 @@ func TestDetectTestCommand_Good_Priority(t *testing.T) {
 	_ = os.WriteFile(filepath.Join(coreDir, "test.yaml"), []byte("command: my-custom-test"), 0644)
 	_ = os.WriteFile(filepath.Join(tmpDir, "go.mod"), []byte("module example"), 0644)
 
-	cmd := DetectTestCommand(tmpDir)
+	cmd := DetectTestCommand(io.Local, tmpDir)
 	if cmd != "my-custom-test" {
 		t.Errorf("expected 'my-custom-test' (from .core/test.yaml), got %q", cmd)
 	}
@@ -108,7 +110,7 @@ env:
 `
 	_ = os.WriteFile(filepath.Join(coreDir, "test.yaml"), []byte(configYAML), 0644)
 
-	cfg, err := LoadTestConfig(tmpDir)
+	cfg, err := LoadTestConfig(io.Local, tmpDir)
 	if err != nil {
 		t.Fatalf("unexpected error: %v", err)
 	}
@@ -133,7 +135,7 @@ env:
 func TestLoadTestConfig_Bad_NotFound(t *testing.T) {
 	tmpDir := t.TempDir()
 
-	_, err := LoadTestConfig(tmpDir)
+	_, err := LoadTestConfig(io.Local, tmpDir)
 	if err == nil {
 		t.Error("expected error for missing config, got nil")
 	}
@@ -143,10 +145,10 @@ func TestHasPackageScript_Good(t *testing.T) {
 	tmpDir := t.TempDir()
 	_ = os.WriteFile(filepath.Join(tmpDir, "package.json"), []byte(`{"scripts":{"test":"jest","build":"webpack"}}`), 0644)
 
-	if !hasPackageScript(tmpDir, "test") {
+	if !hasPackageScript(io.Local, tmpDir, "test") {
 		t.Error("expected to find 'test' script")
 	}
-	if !hasPackageScript(tmpDir, "build") {
+	if !hasPackageScript(io.Local, tmpDir, "build") {
 		t.Error("expected to find 'build' script")
 	}
 }
@@ -155,7 +157,7 @@ func TestHasPackageScript_Bad_MissingScript(t *testing.T) {
 	tmpDir := t.TempDir()
 	_ = os.WriteFile(filepath.Join(tmpDir, "package.json"), []byte(`{"scripts":{"build":"webpack"}}`), 0644)
 
-	if hasPackageScript(tmpDir, "test") {
+	if hasPackageScript(io.Local, tmpDir, "test") {
 		t.Error("expected not to find 'test' script")
 	}
 }
@@ -164,7 +166,7 @@ func TestHasComposerScript_Good(t *testing.T) {
 	tmpDir := t.TempDir()
 	_ = os.WriteFile(filepath.Join(tmpDir, "composer.json"), []byte(`{"scripts":{"test":"pest","post-install-cmd":"@php artisan migrate"}}`), 0644)
 
-	if !hasComposerScript(tmpDir, "test") {
+	if !hasComposerScript(io.Local, tmpDir, "test") {
 		t.Error("expected to find 'test' script")
 	}
 }
@@ -173,7 +175,7 @@ func TestHasComposerScript_Bad_MissingScript(t *testing.T) {
 	tmpDir := t.TempDir()
 	_ = os.WriteFile(filepath.Join(tmpDir, "composer.json"), []byte(`{"scripts":{"build":"@php build.php"}}`), 0644)
 
-	if hasComposerScript(tmpDir, "test") {
+	if hasComposerScript(io.Local, tmpDir, "test") {
 		t.Error("expected not to find 'test' script")
 	}
 }
@@ -229,7 +231,7 @@ func TestDetectTestCommand_Good_TaskfileYml(t *testing.T) {
 	tmpDir := t.TempDir()
 	_ = os.WriteFile(filepath.Join(tmpDir, "Taskfile.yml"), []byte("version: '3'"), 0644)
 
-	cmd := DetectTestCommand(tmpDir)
+	cmd := DetectTestCommand(io.Local, tmpDir)
 	if cmd != "task test" {
 		t.Errorf("expected 'task test', got %q", cmd)
 	}
@@ -239,7 +241,7 @@ func TestDetectTestCommand_Good_Pyproject(t *testing.T) {
 	tmpDir := t.TempDir()
 	_ = os.WriteFile(filepath.Join(tmpDir, "pyproject.toml"), []byte("[tool.pytest]"), 0644)
 
-	cmd := DetectTestCommand(tmpDir)
+	cmd := DetectTestCommand(io.Local, tmpDir)
 	if cmd != "pytest" {
 		t.Errorf("expected 'pytest', got %q", cmd)
 	}
@@ -248,7 +250,7 @@ func TestDetectTestCommand_Good_Pyproject(t *testing.T) {
 func TestHasPackageScript_Bad_NoFile(t *testing.T) {
 	tmpDir := t.TempDir()
 
-	if hasPackageScript(tmpDir, "test") {
+	if hasPackageScript(io.Local, tmpDir, "test") {
 		t.Error("expected false for missing package.json")
 	}
 }
@@ -257,7 +259,7 @@ func TestHasPackageScript_Bad_InvalidJSON(t *testing.T) {
 	tmpDir := t.TempDir()
 	_ = os.WriteFile(filepath.Join(tmpDir, "package.json"), []byte(`invalid json`), 0644)
 
-	if hasPackageScript(tmpDir, "test") {
+	if hasPackageScript(io.Local, tmpDir, "test") {
 		t.Error("expected false for invalid JSON")
 	}
 }
@@ -266,7 +268,7 @@ func TestHasPackageScript_Bad_NoScripts(t *testing.T) {
 	tmpDir := t.TempDir()
 	_ = os.WriteFile(filepath.Join(tmpDir, "package.json"), []byte(`{"name":"test"}`), 0644)
 
-	if hasPackageScript(tmpDir, "test") {
+	if hasPackageScript(io.Local, tmpDir, "test") {
 		t.Error("expected false for missing scripts section")
 	}
 }
@@ -274,7 +276,7 @@ func TestHasPackageScript_Bad_NoScripts(t *testing.T) {
 func TestHasComposerScript_Bad_NoFile(t *testing.T) {
 	tmpDir := t.TempDir()
 
-	if hasComposerScript(tmpDir, "test") {
+	if hasComposerScript(io.Local, tmpDir, "test") {
 		t.Error("expected false for missing composer.json")
 	}
 }
@@ -283,7 +285,7 @@ func TestHasComposerScript_Bad_InvalidJSON(t *testing.T) {
 	tmpDir := t.TempDir()
 	_ = os.WriteFile(filepath.Join(tmpDir, "composer.json"), []byte(`invalid json`), 0644)
 
-	if hasComposerScript(tmpDir, "test") {
+	if hasComposerScript(io.Local, tmpDir, "test") {
 		t.Error("expected false for invalid JSON")
 	}
 }
@@ -292,7 +294,7 @@ func TestHasComposerScript_Bad_NoScripts(t *testing.T) {
 	tmpDir := t.TempDir()
 	_ = os.WriteFile(filepath.Join(tmpDir, "composer.json"), []byte(`{"name":"test/pkg"}`), 0644)
 
-	if hasComposerScript(tmpDir, "test") {
+	if hasComposerScript(io.Local, tmpDir, "test") {
 		t.Error("expected false for missing scripts section")
 	}
 }
@@ -303,7 +305,7 @@ func TestLoadTestConfig_Bad_InvalidYAML(t *testing.T) {
 	_ = os.MkdirAll(coreDir, 0755)
 	_ = os.WriteFile(filepath.Join(coreDir, "test.yaml"), []byte("invalid: yaml: :"), 0644)
 
-	_, err := LoadTestConfig(tmpDir)
+	_, err := LoadTestConfig(io.Local, tmpDir)
 	if err == nil {
 		t.Error("expected error for invalid YAML")
 	}
@@ -315,7 +317,7 @@ func TestLoadTestConfig_Good_MinimalConfig(t *testing.T) {
 	_ = os.MkdirAll(coreDir, 0755)
 	_ = os.WriteFile(filepath.Join(coreDir, "test.yaml"), []byte("version: 1"), 0644)
 
-	cfg, err := LoadTestConfig(tmpDir)
+	cfg, err := LoadTestConfig(io.Local, tmpDir)
 	if err != nil {
 		t.Fatalf("unexpected error: %v", err)
 	}
@@ -332,7 +334,7 @@ func TestDetectTestCommand_Good_ComposerWithoutScript(t *testing.T) {
 	// composer.json without test script should not return composer test
 	_ = os.WriteFile(filepath.Join(tmpDir, "composer.json"), []byte(`{"name":"test/pkg"}`), 0644)
 
-	cmd := DetectTestCommand(tmpDir)
+	cmd := DetectTestCommand(io.Local, tmpDir)
 	// Falls through to empty (no match)
 	if cmd != "" {
 		t.Errorf("expected empty string, got %q", cmd)
@@ -344,7 +346,7 @@ func TestDetectTestCommand_Good_PackageJSONWithoutScript(t *testing.T) {
 	// package.json without test or dev script
 	_ = os.WriteFile(filepath.Join(tmpDir, "package.json"), []byte(`{"name":"test"}`), 0644)
 
-	cmd := DetectTestCommand(tmpDir)
+	cmd := DetectTestCommand(io.Local, tmpDir)
 	// Falls through to empty
 	if cmd != "" {
 		t.Errorf("expected empty string, got %q", cmd)