feat: scaffold codespace backend

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

internal/process/manager_test.go

@@ -0,0 +1,61 @@
+package process
+
+import (
+	"os"
+	"testing"
+
+	"codespace/internal/util"
+)
+
+func TestStatusBeforeStartIsNotRunning(t *testing.T) {
+	m := NewManager("opencode")
+	s := m.Status("ws1")
+	if s.Running {
+		t.Error("expected Running=false before start")
+	}
+	if s.PID != 0 {
+		t.Errorf("expected PID=0, got %d", s.PID)
+	}
+}
+
+func TestStartRejectsDuplicateRunningSession(t *testing.T) {
+	m := NewManager("")
+	// Override command for testing using the test binary itself.
+	m.command = os.Args[0]
+	m.args = []string{"-test.run=TestHelperProcess", "--"}
+	// Set env so the helper process enters its blocking select loop.
+	t.Setenv("CODESPACE_HELPER_PROCESS", "1")
+
+	root := t.TempDir()
+
+	if err := m.Start("ws1", root); err != nil {
+		t.Fatalf("first Start: %v", err)
+	}
+	defer m.Stop("ws1")
+
+	err := m.Start("ws1", root)
+	if err == nil {
+		t.Fatal("expected error on duplicate start")
+	}
+	if code := util.CodeOf(err); code != util.CodeConflict {
+		t.Errorf("expected conflict error, got %v", err)
+	}
+}
+
+func TestStopMissingSessionIsNotFound(t *testing.T) {
+	m := NewManager("opencode")
+	err := m.Stop("nonexistent")
+	if err == nil {
+		t.Fatal("expected error stopping missing session")
+	}
+	if code := util.CodeOf(err); code != util.CodeNotFound {
+		t.Errorf("expected not_found error, got %v", err)
+	}
+}
+
+func TestHelperProcess(t *testing.T) {
+	if os.Getenv("CODESPACE_HELPER_PROCESS") != "1" {
+		return
+	}
+	select {}
+}