fix: address review findings for self-update (#15)

internal/agent/updater/compose_test.go

@@ -64,6 +64,7 @@ type fakeHelper struct {
 	hold      bool   // ContainerWait never reports an exit
 	logs      string // what the helper printed
 	onStart   func()
+	state     container.ContainerState // what an inspect reports; exited when empty
 
 	created  []createdHelper
 	started  []string
@@ -79,6 +80,14 @@ func (h *fakeHelper) ContainerCreate(_ context.Context, cfg *container.Config, h
 	return container.CreateResponse{ID: "helper1"}, nil
 }
 
+func (h *fakeHelper) ContainerInspect(context.Context, string) (container.InspectResponse, error) {
+	state := h.state
+	if state == "" {
+		state = container.StateExited
+	}
+	return container.InspectResponse{ContainerJSONBase: &container.ContainerJSONBase{State: &container.State{Status: state}}}, nil
+}
+
 func (h *fakeHelper) ContainerStart(_ context.Context, id string, _ container.StartOptions) error {
 	h.started = append(h.started, id)
 	if h.onStart != nil {
@@ -116,6 +125,14 @@ type fakeHelperCompose struct {
 	h *fakeHelper
 }
 
+// ContainerInspect answers for the agent's own container ("me") like fakeCompose
+// and for any other ID like the helper.
+func (f fakeHelperCompose) ContainerInspect(ctx context.Context, id string) (container.InspectResponse, error) {
+	if id == "me" {
+		return f.fakeCompose.ContainerInspect(ctx, id)
+	}
+	return f.h.ContainerInspect(ctx, id)
+}
 func (f fakeHelperCompose) ContainerCreate(ctx context.Context, cfg *container.Config, host *container.HostConfig, n *network.NetworkingConfig, p *ocispec.Platform, name string) (container.CreateResponse, error) {
 	return f.h.ContainerCreate(ctx, cfg, host, n, p, name)
 }
@@ -528,13 +545,13 @@ func TestComposeSelfUpdate(t *testing.T) {
 			assert.Equal(t, container.WaitConditionNextExit, c.helper.waitCond)
 			labels := cfg.Labels
 			assert.Len(t, labels, 6, "no compose labels")
-			assert.Equal(t, "7", labels[protocol.LabelSelfUpdateJob])
-			assert.Equal(t, pinned, labels[protocol.LabelSelfUpdateRef])
-			assert.Equal(t, "2026-10-13T09:00:00Z", labels[protocol.LabelSelfUpdateStarted])
-			assert.Equal(t, "updater", labels[protocol.LabelSelfUpdateProject])
-			assert.Equal(t, "agent", labels[protocol.LabelSelfUpdateService])
-			assert.Contains(t, labels[protocol.LabelSelfUpdateOutput], "resolved "+pinned)
-			assert.Contains(t, labels[protocol.LabelSelfUpdateOutput], "$ docker "+strings.Join(withStep("pull", "agent"), " "))
+			assert.Equal(t, "7", labels[labelSelfUpdateJob])
+			assert.Equal(t, pinned, labels[labelSelfUpdateRef])
+			assert.Equal(t, "2026-10-13T09:00:00Z", labels[labelSelfUpdateStarted])
+			assert.Equal(t, "updater", labels[labelSelfUpdateProject])
+			assert.Equal(t, "agent", labels[labelSelfUpdateService])
+			assert.Contains(t, labels[labelSelfUpdateOutput], "resolved "+pinned)
+			assert.Contains(t, labels[labelSelfUpdateOutput], "$ docker "+strings.Join(withStep("pull", "agent"), " "))
 		})
 	}