--- a/tests/test-topic-stack.t	Wed May 17 00:23:19 2017 +0200
+++ b/tests/test-topic-stack.t	Wed May 17 09:52:06 2017 +0200
@@ -77,6 +77,53 @@
   t2: c_d
   t1: c_c
     ^ c_b
+  $ hg stack -Tjson | python -m json.tool
+  [
+      {
+          "isentry": true,
+          "topic.stack.desc": "c_f",
+          "topic.stack.index": 4,
+          "topic.stack.state": [
+              "current"
+          ],
+          "topic.stack.state.symbol": "@"
+      },
+      {
+          "isentry": true,
+          "topic.stack.desc": "c_e",
+          "topic.stack.index": 3,
+          "topic.stack.state": [
+              "clean"
+          ],
+          "topic.stack.state.symbol": ":"
+      },
+      {
+          "isentry": true,
+          "topic.stack.desc": "c_d",
+          "topic.stack.index": 2,
+          "topic.stack.state": [
+              "clean"
+          ],
+          "topic.stack.state.symbol": ":"
+      },
+      {
+          "isentry": true,
+          "topic.stack.desc": "c_c",
+          "topic.stack.index": 1,
+          "topic.stack.state": [
+              "clean"
+          ],
+          "topic.stack.state.symbol": ":"
+      },
+      {
+          "isentry": false,
+          "topic.stack.desc": "c_b",
+          "topic.stack.state": [
+              "base"
+          ],
+          "topic.stack.state.symbol": "^"
+      }
+  ]
 
 error case, nothing to list
 
@@ -135,6 +182,26 @@
   t2@ c_d (current)
   t1: c_c
     ^ c_b
+  $ hg up t3
+  2 files updated, 0 files merged, 0 files removed, 0 files unresolved
+  $ hg topic --list
+  ### topic: foo
+  ### branch: default
+  t4$ c_f (unstable)
+  t3@ c_e (current)
+  t2: c_d
+  t1: c_c
+    ^ c_b
+  $ hg topic --list --color=debug
+  [topic.stack.summary.topic|### topic: [topic.active|foo]]
+  [topic.stack.summary.branches|### branch: default]
+  [topic.stack.index topic.stack.index.unstable|t4][topic.stack.state topic.stack.state.unstable|$] [topic.stack.desc topic.stack.desc.unstable|c_f][topic.stack.state topic.stack.state.unstable| (unstable)]
+  [topic.stack.index topic.stack.index.current|t3][topic.stack.state topic.stack.state.current|@] [topic.stack.desc topic.stack.desc.current|c_e][topic.stack.state topic.stack.state.current| (current)]
+  [topic.stack.index topic.stack.index.clean|t2][topic.stack.state topic.stack.state.clean|:] [topic.stack.desc topic.stack.desc.clean|c_d]
+  [topic.stack.index topic.stack.index.clean|t1][topic.stack.state topic.stack.state.clean|:] [topic.stack.desc topic.stack.desc.clean|c_c]
+    [topic.stack.state topic.stack.state.base|^] [topic.stack.desc topic.stack.desc.base|c_b]
+  $ hg up t2
+  1 files updated, 0 files merged, 1 files removed, 0 files unresolved
 
 Also test the revset: