Some free tests from a debugging session

The session was unfruitful, but I guess the tests were not necessarily

test/rebar_resource_SUITE.erl

@@ -0,0 +1,33 @@
+-module(rebar_resource_SUITE).
+-compile(export_all).
+-include_lib("common_test/include/ct.hrl").
+-include_lib("eunit/include/eunit.hrl").
+
+all() -> [{group, git}, {group, pkg}, {group, hg}].
+
+groups() ->
+    [{all, [], [change_type_upgrade]},
+     {git, [], [{group, all}]},
+     {pkg, [], [{group, all}]},
+     {hg, [], [{group, all}]}].
+
+init_per_group(all, Config) ->
+    Config;
+init_per_group(Name, Config) ->
+    [{type, Name},
+     {resource, {Name, "https://example.org/user/app", "vsn"}} | Config].
+
+%% Changing the resource type is seen as an upgrade
+init_per_testcase(change_type_upgrade, Config) ->
+    Type = ?config(type, Config),
+    TypeStr = atom_to_list(Type),
+    DirName = filename:join([?config(priv_dir, Config), "resource_"++TypeStr]),
+    ec_file:mkdir_path(DirName),
+    [{path, DirName} | Config].
+
+end_per_testcase(_, Config) ->
+    Config.
+
+change_type_upgrade(Config) ->
+    ?assert(rebar_fetch:needs_update(?config(path, Config),
+                                     ?config(resource, Config))).