Handle empty maps in active_tasks data structure

Empty maps maybe useful to initialize the data in some cases but we don't want
to emit an entry in the output with just an empty map.

While at it, add some tests to check the basics.

2 files changed, 122 insertions, 1 deletions

diff --git a/src/fabric/src/fabric2_active_tasks.erl b/src/fabric/src/fabric2_active_tasks.erl
index 2c03ec3a9..e706ebaa4 100644
--- a/src/fabric/src/fabric2_active_tasks.erl
+++ b/src/fabric/src/fabric2_active_tasks.erl
@@ -34,7 +34,8 @@ get_active_tasks() ->
                 {ok, Data} = couch_jobs:get_job_data(JTx, Type, JobId),
                 case maps:get(?ACTIVE_TASK_INFO, Data, not_found) of
                     not_found -> false;
-                    Info -> {true, Info}
+                    #{} = Map when map_size(Map) == 0 -> false;
+                    #{} = Info -> {true, Info}
                 end
             end, JobIds),
             TaskAcc ++ Tasks
diff --git a/src/fabric/test/fabric2_active_tasks_tests.erl b/src/fabric/test/fabric2_active_tasks_tests.erl
new file mode 100644
index 000000000..891450027
--- /dev/null
+++ b/src/fabric/test/fabric2_active_tasks_tests.erl
@@ -0,0 +1,120 @@
+% Licensed under the Apache License, Version 2.0 (the "License"); you may not
+% use this file except in compliance with the License. You may obtain a copy of
+% the License at
+%
+%   http://www.apache.org/licenses/LICENSE-2.0
+%
+% Unless required by applicable law or agreed to in writing, software
+% distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+% WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+% License for the specific language governing permissions and limitations under
+% the License.
+
+-module(fabric2_active_tasks_tests).
+
+
+-include_lib("couch/include/couch_eunit.hrl").
+-include_lib("eunit/include/eunit.hrl").
+-include_lib("couch/include/couch_db.hrl").
+-include("fabric2_test.hrl").
+
+
+-define(JOB_TYPE, <<"fabric2_active_tasks_tests_type">>).
+-define(JOB_ID, <<"job_id">>).
+
+
+active_tasks_test_() ->
+    {
+        "Test cleanup of stale indices",
+        {
+            setup,
+            fun setup_all/0,
+            fun cleanup_all/1,
+            {
+                foreach,
+                fun setup/0,
+                fun cleanup/1,
+                [
+                    ?TDEF_FE(no_active_tasks_defined),
+                    ?TDEF_FE(empty_map_info),
+                    ?TDEF_FE(can_read_active_tasks),
+                    ?TDEF_FE(only_running_tasks_appear)
+                ]
+            }
+        }
+    }.
+
+
+setup_all() ->
+    Ctx = test_util:start_couch([fabric, couch_jobs]),
+    couch_jobs:set_type_timeout(?JOB_TYPE, 5000),
+    meck:new(couch_jobs, [passthrough]),
+    meck:expect(couch_jobs, get_types, 1, [?JOB_TYPE]),
+    Ctx.
+
+
+cleanup_all(Ctx) ->
+    meck:unload(),
+    test_util:stop_couch(Ctx).
+
+
+setup() ->
+    ok = couch_jobs:add(undefined, ?JOB_TYPE, ?JOB_ID, #{}),
+    ok.
+
+
+cleanup(_) ->
+    meck:reset(couch_jobs),
+    couch_jobs:remove(undefined, ?JOB_TYPE, ?JOB_ID).
+
+
+no_active_tasks_defined(_) ->
+    {ok, Job1, #{}} = couch_jobs:accept(?JOB_TYPE),
+    ?assertEqual([], fabric2_active_tasks:get_active_tasks()),
+    ok = couch_jobs:finish(undefined, Job1).
+
+
+empty_map_info(_) ->
+    {ok, Job1, Data} = couch_jobs:accept(?JOB_TYPE),
+
+    Data1 = fabric2_active_tasks:update_active_task_info(Data, #{}),
+    {ok, Job2} = couch_jobs:update(undefined, Job1, Data1),
+    ?assertEqual([], fabric2_active_tasks:get_active_tasks()),
+    ok = couch_jobs:finish(undefined, Job2).
+
+
+can_read_active_tasks(_) ->
+    {ok, Job1, Data} = couch_jobs:accept(?JOB_TYPE),
+
+    Info = #{<<"x">> => 1},
+    Data1 = fabric2_active_tasks:update_active_task_info(Data, Info),
+    {ok, Job2} = couch_jobs:update(undefined, Job1, Data1),
+    ?assertEqual([#{<<"x">> => 1}], fabric2_active_tasks:get_active_tasks()),
+
+    Info1 = fabric2_active_tasks:get_active_task_info(Data1),
+    Info2 = Info1#{<<"y">> => 2},
+    Data2 = fabric2_active_tasks:update_active_task_info(Data1, Info2),
+    {ok, Job3} = couch_jobs:update(undefined, Job2, Data2),
+    ?assertEqual([#{<<"x">> => 1, <<"y">> => 2}],
+        fabric2_active_tasks:get_active_tasks()),
+    ok = couch_jobs:finish(undefined, Job3).
+
+
+only_running_tasks_appear(_) ->
+    {ok, Job1, Data} = couch_jobs:accept(?JOB_TYPE),
+
+    Info = #{<<"x">> => 1},
+    Data1 = fabric2_active_tasks:update_active_task_info(Data, Info),
+    {ok, Job2} = couch_jobs:update(undefined, Job1, Data1),
+
+    ?assertEqual([#{<<"x">> => 1}], fabric2_active_tasks:get_active_tasks()),
+    {ok, _} = couch_jobs:resubmit(undefined, Job2),
+
+    ok = couch_jobs:finish(undefined, Job2),
+
+    ?assertEqual([], fabric2_active_tasks:get_active_tasks()),
+    {ok, Job3, #{}} = couch_jobs:accept(?JOB_TYPE),
+    ?assertEqual([#{<<"x">> => 1}], fabric2_active_tasks:get_active_tasks()),
+
+    ok = couch_jobs:finish(undefined, Job3),
+    ?assertEqual([], fabric2_active_tasks:get_active_tasks()).