refactor(stamus): replace global function pointers with interface-based DI

Introduce FileOpener and ContainerLister interfaces with a ConfigManager
struct that holds dependencies. Move package-level functions to methods
on ConfigManager and add backward-compatible wrapper functions so
external callers remain unchanged.

Tests now use mock implementations per test instead of mutating shared
global function pointers, making them safe for t.Parallel().

Author: LeVraiBaptiste

internal/stamus/config.go

@@ -85,18 +85,3 @@ func GetConfigsList() ([]string, error) {
 	return configs, nil
 }
 
-// GetProjectName returns the project name for a given config folder path.
-// Returns empty string if the folder is not found in the instances.
-func GetProjectName(folder string) string {
-	config, err := GetStamusConfig()
-	if err != nil {
-		return ""
-	}
-	if config.Instances == nil {
-		return ""
-	}
-	if infos, ok := config.Instances[Folder(folder)]; ok {
-		return infos.Project
-	}
-	return ""
-}

internal/stamus/deps.go

@@ -0,0 +1,71 @@
+package stamus
+
+import (
+	"context"
+	"io"
+	"os"
+
+	"github.com/docker/docker/api/types"
+	"github.com/docker/docker/api/types/container"
+	"github.com/docker/docker/api/types/filters"
+	"github.com/docker/docker/client"
+)
+
+// FileOpener abstracts file system operations for config management.
+type FileOpener interface {
+	MkdirAll(path string, perm os.FileMode) error
+	OpenFile(name string, flag int, perm os.FileMode) (*os.File, error)
+	ReadAll(r io.Reader) ([]byte, error)
+}
+
+// ContainerLister abstracts Docker container queries.
+type ContainerLister interface {
+	GetContainersByProject(projectName string) ([]types.Container, error)
+}
+
+// ConfigManager holds dependencies for config and instance operations.
+type ConfigManager struct {
+	fs         FileOpener
+	containers ContainerLister
+}
+
+// NewConfigManager creates a ConfigManager with the given dependencies.
+func NewConfigManager(fs FileOpener, containers ContainerLister) *ConfigManager {
+	return &ConfigManager{fs: fs, containers: containers}
+}
+
+// osFileOpener implements FileOpener with real OS calls.
+type osFileOpener struct{}
+
+func (o *osFileOpener) MkdirAll(path string, perm os.FileMode) error {
+	return os.MkdirAll(path, perm)
+}
+
+func (o *osFileOpener) OpenFile(name string, flag int, perm os.FileMode) (*os.File, error) {
+	return os.OpenFile(name, flag, perm)
+}
+
+func (o *osFileOpener) ReadAll(r io.Reader) ([]byte, error) {
+	return io.ReadAll(r)
+}
+
+// dockerContainerLister implements ContainerLister with real Docker API.
+type dockerContainerLister struct{}
+
+func (d *dockerContainerLister) GetContainersByProject(projectName string) ([]types.Container, error) {
+	apiClient, err := client.NewClientWithOpts(client.FromEnv)
+	if err != nil {
+		return nil, err
+	}
+	defer apiClient.Close()
+
+	return apiClient.ContainerList(context.Background(), container.ListOptions{
+		All: true,
+		Filters: filters.NewArgs(
+			filters.Arg("label", "com.docker.compose.project="+projectName),
+		),
+	})
+}
+
+// DefaultManager is the package-level ConfigManager used by backward-compatible wrapper functions.
+var DefaultManager = NewConfigManager(&osFileOpener{}, &dockerContainerLister{})

internal/stamus/fs.go

@@ -1,56 +1,47 @@
 package stamus
 
 import (
-	// Common
 	"encoding/json"
-	"io"
 	"os"
 	"path/filepath"
 
-	// Custom
 	"stamus-ctl/internal/app"
 )
 
-var (
-	osMkdirAll = os.MkdirAll
-	osOpenFile = os.OpenFile
-	ioReadAll  = io.ReadAll
-)
-
-func getOrCreateStamusConfigFile() (*os.File, error) {
+func (cm *ConfigManager) getOrCreateConfigFile() (*os.File, error) {
 	// Create ~/stamus directory
-	err := osMkdirAll(app.ConfigFolder, 0o755)
+	err := cm.fs.MkdirAll(app.ConfigFolder, 0o755)
 	if err != nil {
 		return nil, err
 	}
 
 	// Open or create ~/stamus/config.json
-	f, err := osOpenFile(filepath.Join(app.ConfigFolder, "config.json"), os.O_RDWR|os.O_CREATE, 0o755)
+	f, err := cm.fs.OpenFile(filepath.Join(app.ConfigFolder, "config.json"), os.O_RDWR|os.O_CREATE, 0o755)
 	if err != nil {
 		return nil, err
 	}
 
 	return f, nil
 }
 
-func tryGetStamusConfigFile() (*os.File, error) {
-	// Open or create ~/stamus/config.json
-	f, err := osOpenFile(filepath.Join(app.ConfigFolder, "config.json"), os.O_RDONLY, 0o755)
+func (cm *ConfigManager) tryGetConfigFile() (*os.File, error) {
+	// Open ~/stamus/config.json
+	f, err := cm.fs.OpenFile(filepath.Join(app.ConfigFolder, "config.json"), os.O_RDONLY, 0o755)
 	if err != nil {
 		return nil, err
 	}
 
 	return f, nil
 }
 
-func GetStamusConfig() (*Config, error) {
+func (cm *ConfigManager) GetConfig() (*Config, error) {
 	// Open or create ~/stamus/config.json
-	file, err := tryGetStamusConfigFile()
+	file, err := cm.tryGetConfigFile()
 	if err != nil {
 		return &Config{}, nil
 	}
 	// Read the file contents
-	bytes, err := ioReadAll(file)
+	bytes, err := cm.fs.ReadAll(file)
 	if err != nil {
 		return &Config{}, nil
 	}
@@ -65,3 +56,13 @@ func GetStamusConfig() (*Config, error) {
 
 	return config, nil
 }
+
+// Backward-compatible package-level functions
+
+func getOrCreateStamusConfigFile() (*os.File, error) {
+	return DefaultManager.getOrCreateConfigFile()
+}
+
+func GetStamusConfig() (*Config, error) {
+	return DefaultManager.GetConfig()
+}