add per-OS file variants via files.<os>/ directories

internal/core/ops_test.go

@@ -4,6 +4,7 @@ import (
 	"os"
 	"path/filepath"
 	"regexp"
+	"strings"
 	"testing"
 )
 
@@ -304,3 +305,121 @@ func TestRestoreOne(t *testing.T) {
 		t.Errorf("wrong content after restore: %s", string(content))
 	}
 }
+
+func TestApplyPackages_Overlay(t *testing.T) {
+	tmp := t.TempDir()
+	baseDir := filepath.Join(tmp, "files")
+	linuxDir := filepath.Join(tmp, "files.linux")
+	targetDir := filepath.Join(tmp, "target")
+
+	// Create base files
+	if err := os.MkdirAll(baseDir, 0o755); err != nil {
+		t.Fatalf("failed to create base dir: %v", err)
+	}
+	baseFile := filepath.Join(baseDir, "common.txt")
+	if err := os.WriteFile(baseFile, []byte("common"), 0o644); err != nil {
+		t.Fatalf("failed to create base file: %v", err)
+	}
+	sharedFile := filepath.Join(baseDir, "shared.txt")
+	if err := os.WriteFile(sharedFile, []byte("shared"), 0o644); err != nil {
+		t.Fatalf("failed to create shared file: %v", err)
+	}
+
+	// Create Linux-specific override
+	if err := os.MkdirAll(linuxDir, 0o755); err != nil {
+		t.Fatalf("failed to create linux dir: %v", err)
+	}
+	linuxFile := filepath.Join(linuxDir, "common.txt") // overrides base
+	if err := os.WriteFile(linuxFile, []byte("linux"), 0o644); err != nil {
+		t.Fatalf("failed to create linux file: %v", err)
+	}
+
+	cfg := &packageConfig{}
+	filesDirs := []string{baseDir, linuxDir}
+
+	// Apply both directories
+	if err := ApplyPackages(filesDirs, targetDir, cfg); err != nil {
+		t.Errorf("ApplyPackages failed: %v", err)
+	}
+
+	// Verify shared file from base is linked
+	targetShared := filepath.Join(targetDir, "shared.txt")
+	content, err := os.ReadFile(targetShared)
+	if err != nil {
+		t.Errorf("shared file not found: %v", err)
+	} else if string(content) != "shared" {
+		t.Errorf("shared file wrong content: %s", string(content))
+	}
+
+	// Verify common.txt is overridden by Linux variant
+	targetCommon := filepath.Join(targetDir, "common.txt")
+	content, err = os.ReadFile(targetCommon)
+	if err != nil {
+		t.Errorf("common file not found: %v", err)
+	} else if string(content) != "linux" {
+		t.Errorf("common file should be overridden by linux variant, got: %s", string(content))
+	}
+
+	// Verify symlink points to linux variant
+	src, err := os.Readlink(targetCommon)
+	if err != nil {
+		t.Errorf("failed to read symlink: %v", err)
+	} else if !strings.HasSuffix(src, "files.linux/common.txt") {
+		t.Errorf("symlink should point to linux variant, got: %s", src)
+	}
+}
+
+func TestFindStaleLinksMulti_WithVariants(t *testing.T) {
+	tmp := t.TempDir()
+	baseDir := filepath.Join(tmp, "files")
+	linuxDir := filepath.Join(tmp, "files.linux")
+	targetDir := filepath.Join(tmp, "target")
+
+	if err := os.MkdirAll(baseDir, 0o755); err != nil {
+		t.Fatalf("failed to create base dir: %v", err)
+	}
+	if err := os.MkdirAll(linuxDir, 0o755); err != nil {
+		t.Fatalf("failed to create linux dir: %v", err)
+	}
+	if err := os.MkdirAll(targetDir, 0o755); err != nil {
+		t.Fatalf("failed to create target dir: %v", err)
+	}
+
+	// Create files
+	baseFile := filepath.Join(baseDir, "base.txt")
+	if err := os.WriteFile(baseFile, []byte("base"), 0o644); err != nil {
+		t.Fatalf("failed to create base file: %v", err)
+	}
+	linuxFile := filepath.Join(linuxDir, "linux.txt")
+	if err := os.WriteFile(linuxFile, []byte("linux"), 0o644); err != nil {
+		t.Fatalf("failed to create linux file: %v", err)
+	}
+
+	// Create symlinks
+	targetBase := filepath.Join(targetDir, "base.txt")
+	if err := os.Symlink(baseFile, targetBase); err != nil {
+		t.Fatalf("failed to create base symlink: %v", err)
+	}
+	targetLinux := filepath.Join(targetDir, "linux.txt")
+	if err := os.Symlink(linuxFile, targetLinux); err != nil {
+		t.Fatalf("failed to create linux symlink: %v", err)
+	}
+
+	// Delete the linux source file to create a stale link
+	if err := os.Remove(linuxFile); err != nil {
+		t.Fatalf("failed to remove linux file: %v", err)
+	}
+
+	filesDirs := []string{baseDir, linuxDir}
+	stale, err := FindStaleLinksMulti(filesDirs, targetDir)
+	if err != nil {
+		t.Errorf("FindStaleLinksMulti failed: %v", err)
+	}
+
+	if len(stale) != 1 {
+		t.Errorf("expected 1 stale link, got %d", len(stale))
+	}
+	if len(stale) > 0 && stale[0] != targetLinux {
+		t.Errorf("expected stale link to be %s, got %s", targetLinux, stale[0])
+	}
+}