allow using an alternate regex to locate test modules during eunit runs

{`eunit_test_regex`, Regex}` will use the supplied `Regex` instead of
the default to locate tests in test dirs. note this matches only the
filename, not the path. the regex is applied to all test dirs, recursively

fixes #1331

src/rebar_prv_eunit.erl

@@ -18,6 +18,8 @@
 %% we need to modify app_info state before compile
 -define(DEPS, [lock]).
 
+-define(DEFAULT_TEST_REGEX, "^[^._].*\\.erl\$").
+
 %% ===================================================================
 %% Public API
 %% ===================================================================
@@ -174,21 +176,24 @@ set_apps([App|Rest], Acc) ->
 set_modules(Apps, State) -> set_modules(Apps, State, {[], []}).
 
 set_modules([], State, {AppAcc, TestAcc}) ->
-    TestSrc = gather_src([filename:join([rebar_state:dir(State), "test"])]),
+    Regex = rebar_state:get(State, eunit_test_regex, ?DEFAULT_TEST_REGEX),
+    BareTestDir = [filename:join([rebar_state:dir(State), "test"])],
+    TestSrc = gather_src(BareTestDir, Regex),
     dedupe_tests({AppAcc, TestAcc ++ TestSrc});
 set_modules([App|Rest], State, {AppAcc, TestAcc}) ->
     F = fun(Dir) -> filename:join([rebar_app_info:dir(App), Dir]) end,
     AppDirs = lists:map(F, rebar_dir:src_dirs(rebar_app_info:opts(App), ["src"])),
-    AppSrc = gather_src(AppDirs),
+    Regex = rebar_state:get(State, eunit_test_regex, ?DEFAULT_TEST_REGEX),
+    AppSrc = gather_src(AppDirs, Regex),
     TestDirs = [filename:join([rebar_app_info:dir(App), "test"])],
-    TestSrc = gather_src(TestDirs),
+    TestSrc = gather_src(TestDirs, Regex),
     set_modules(Rest, State, {AppSrc ++ AppAcc, TestSrc ++ TestAcc}).
 
-gather_src(Dirs) -> gather_src(Dirs, []).
+gather_src(Dirs, Regex) -> gather_src(Dirs, Regex, []).
 
-gather_src([], Srcs) -> Srcs;
-gather_src([Dir|Rest], Srcs) ->
-    gather_src(Rest, Srcs ++ rebar_utils:find_files(Dir, "^[^._].*\\.erl\$", true)).
+gather_src([], _Regex, Srcs) -> Srcs;
+gather_src([Dir|Rest], Regex, Srcs) ->
+    gather_src(Rest, Regex, Srcs ++ rebar_utils:find_files(Dir, Regex, true)).
 
 dedupe_tests({AppMods, TestMods}) ->
     %% for each modules in TestMods create a test if there is not a module

test/rebar_eunit_SUITE.erl

@@ -18,6 +18,7 @@
 -export([misspecified_eunit_tests/1]).
 -export([misspecified_eunit_compile_opts/1]).
 -export([misspecified_eunit_first_files/1]).
+-export([alternate_test_regex/1]).
 
 -include_lib("common_test/include/ct.hrl").
 -include_lib("eunit/include/eunit.hrl").
@@ -27,7 +28,8 @@ all() ->
     [{group, basic_app}, {group, multi_app}, {group, cmd_line_args},
      misspecified_eunit_tests,
      misspecified_eunit_compile_opts,
-     misspecified_eunit_first_files].
+     misspecified_eunit_first_files,
+     alternate_test_regex].
 
 groups() ->
     [{basic_app, [sequence], [basic_app_compiles, {group, basic_app_results}]},
@@ -579,3 +581,25 @@ misspecified_eunit_first_files(Config) ->
     {error, {rebar_prv_eunit, Error}} = rebar_test_utils:run_and_check(State, RebarConfig, ["eunit"], return),
 
     {badconfig, {"Value `~p' of option `~p' must be a list", {some_file, eunit_first_files}}} = Error.
+
+alternate_test_regex(Config) ->
+    State = rebar_test_utils:init_rebar_state(Config, "alternate_test_regex_"),
+
+    AppDir = ?config(apps, State),
+    PrivDir = ?config(priv_dir, State),
+
+    AppDirs = ["src", "include", "test"],
+
+    lists:foreach(fun(F) -> ec_file:copy(filename:join([PrivDir, "basic_app", F]),
+                                         filename:join([AppDir, F]),
+                                         [recursive]) end, AppDirs),
+
+    BaseConfig = [{erl_opts, [{d, config_define}]}, {eunit_compile_opts, [{d, eunit_compile_define}]}],
+
+    RebarConfig = [{eunit_test_regex, "basic_app_tests.erl"}|BaseConfig],
+
+    {ok, S} = rebar_test_utils:run_and_check(State, RebarConfig, ["as", "test", "lock"], return),
+
+    Set = {ok, [{application, basic_app},
+                {module, basic_app_tests}]},
+    Set = rebar_prv_eunit:prepare_tests(S).