diff --git a/proc_test.go b/proc_test.go
new file mode 100644
index 0000000..9f5eb64
--- /dev/null
+++ b/proc_test.go
@@ -0,0 +1,134 @@
+package main
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+	"testing"
+)
+
+type fakeProcEntry struct {
+	cmdline string // raw content with \x00 separators
+	cwd     string // symlink target
+}
+
+// createFakeProc builds a temporary /proc-like directory structure.
+func createFakeProc(t *testing.T, entries map[int]fakeProcEntry) string {
+	t.Helper()
+	dir := t.TempDir()
+
+	for pid, entry := range entries {
+		pidDir := filepath.Join(dir, fmt.Sprintf("%d", pid))
+		if err := os.MkdirAll(pidDir, 0o755); err != nil {
+			t.Fatal(err)
+		}
+
+		// Write cmdline file
+		if err := os.WriteFile(filepath.Join(pidDir, "cmdline"), []byte(entry.cmdline), 0o644); err != nil {
+			t.Fatal(err)
+		}
+
+		// Create cwd symlink
+		if err := os.Symlink(entry.cwd, filepath.Join(pidDir, "cwd")); err != nil {
+			t.Fatal(err)
+		}
+	}
+
+	return dir
+}
+
+func TestFindClaudeProcesses(t *testing.T) {
+	fakeProc := createFakeProc(t, map[int]fakeProcEntry{
+		100: {cmdline: "claude\x00-c\x00", cwd: "/home/user/project-a"},
+		200: {cmdline: "claude\x00", cwd: "/home/user/project-b"},
+		300: {cmdline: "bash\x00-l\x00", cwd: "/home/user"},
+	})
+
+	procs, err := FindClaudeProcesses(fakeProc)
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+
+	if len(procs) != 2 {
+		t.Fatalf("expected 2 claude processes, got %d", len(procs))
+	}
+
+	// Build a map by PID for order-independent assertions
+	byPID := make(map[int]Process)
+	for _, p := range procs {
+		byPID[p.PID] = p
+	}
+
+	p100, ok := byPID[100]
+	if !ok {
+		t.Fatal("expected process with PID 100")
+	}
+	if p100.Cwd != "/home/user/project-a" {
+		t.Errorf("PID 100 cwd = %q, want %q", p100.Cwd, "/home/user/project-a")
+	}
+	if len(p100.Cmd) != 2 || p100.Cmd[0] != "claude" || p100.Cmd[1] != "-c" {
+		t.Errorf("PID 100 cmd = %v, want [claude -c]", p100.Cmd)
+	}
+
+	p200, ok := byPID[200]
+	if !ok {
+		t.Fatal("expected process with PID 200")
+	}
+	if p200.Cwd != "/home/user/project-b" {
+		t.Errorf("PID 200 cwd = %q, want %q", p200.Cwd, "/home/user/project-b")
+	}
+
+	if _, ok := byPID[300]; ok {
+		t.Error("bash process (PID 300) should not be in results")
+	}
+}
+
+func TestFindClaudeProcesses_PermissionDenied(t *testing.T) {
+	dir := t.TempDir()
+
+	// Create a PID directory with unreadable cmdline
+	pidDir := filepath.Join(dir, "999")
+	if err := os.MkdirAll(pidDir, 0o755); err != nil {
+		t.Fatal(err)
+	}
+	cmdlinePath := filepath.Join(pidDir, "cmdline")
+	if err := os.WriteFile(cmdlinePath, []byte("claude\x00"), 0o000); err != nil {
+		t.Fatal(err)
+	}
+
+	procs, err := FindClaudeProcesses(dir)
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if len(procs) != 0 {
+		t.Errorf("expected 0 processes (permission denied), got %d", len(procs))
+	}
+}
+
+func TestFindClaudeProcesses_EmptyProc(t *testing.T) {
+	dir := t.TempDir()
+
+	procs, err := FindClaudeProcesses(dir)
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if len(procs) != 0 {
+		t.Errorf("expected 0 processes, got %d", len(procs))
+	}
+}
+
+func TestEncodePath(t *testing.T) {
+	got := EncodePath("/home/pierre/Code/vibe/vmux")
+	want := "-home-pierre-Code-vibe-vmux"
+	if got != want {
+		t.Errorf("EncodePath = %q, want %q", got, want)
+	}
+}
+
+func TestEncodePath_DotDir(t *testing.T) {
+	got := EncodePath("/home/pierre/.config/app")
+	want := "-home-pierre--config-app"
+	if got != want {
+		t.Errorf("EncodePath = %q, want %q", got, want)
+	}
+}