internal/outcome: look up pipewire-pulse path

This is for setting up the pipewire-pulse container in shim, for #29.

Signed-off-by: Ophestra <cat@gensokyo.uk>

internal/outcome/sppipewire_test.go

@@ -16,7 +16,7 @@ func TestSpPipeWireOp(t *testing.T) {
 
 	checkOpBehaviour(t, []opBehaviourTestCase{
 		{"not enabled", func(bool, bool) outcomeOp {
-			return spPipeWireOp{}
+			return new(spPipeWireOp)
 		}, func() *hst.Config {
 			c := hst.Template()
 			*c.Enablements = 0
@@ -24,8 +24,12 @@ func TestSpPipeWireOp(t *testing.T) {
 		}, nil, nil, nil, nil, errNotEnabled, nil, nil, nil, nil, nil},
 
 		{"success", func(bool, bool) outcomeOp {
-			return spPipeWireOp{}
-		}, hst.Template, nil, []stub.Call{}, newI().
+			return new(spPipeWireOp)
+		}, func() *hst.Config {
+			c := hst.Template()
+			c.DirectPipeWire = true
+			return c
+		}, nil, []stub.Call{}, newI().
 			// state.instance
 			Ephemeral(system.Process, m(wantInstancePrefix), 0711).
 			// toSystem