Vendor eunit reporter until we can compile rebar libs

3 files changed, 618 insertions, 0 deletions

diff --git a/test/eunit_progress.erl b/test/eunit_progress.erl
new file mode 100644
index 0000000..153130f
--- /dev/null
+++ b/test/eunit_progress.erl
@@ -0,0 +1,592 @@
+%% eunit_formatters https://github.com/seancribbs/eunit_formatters
+%% Changes made to the original code:
+%% - Embedded binomial_heap.erl file contents into current file.
+%% - ignore warnings for heap implementation to keep complete implementation.
+%% - removed "namespaced_dicts" dependant preprocessor directive, 
+%%   as it does not apply for our project, we just assume OTP version >= 17.
+%%   This is because the previous verison uses rebar, and we won't do that.
+
+%% Copyright 2014 Sean Cribbs
+%%
+%% 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.
+
+
+%% @doc A listener/reporter for eunit that prints '.' for each
+%% success, 'F' for each failure, and 'E' for each error. It can also
+%% optionally summarize the failures at the end.
+-compile({nowarn_unused_function, [insert/2, to_list/1, to_list/2, size/1]}).
+-module(eunit_progress).
+-behaviour(eunit_listener).
+-define(NOTEST, true).
+-include_lib("eunit/include/eunit.hrl").
+
+-define(RED, "\e[0;31m").
+-define(GREEN, "\e[0;32m").
+-define(YELLOW, "\e[0;33m").
+-define(WHITE, "\e[0;37m").
+-define(CYAN, "\e[0;36m").
+-define(RESET, "\e[0m").
+
+-record(node,{
+          rank = 0    :: non_neg_integer(),
+          key         :: term(),
+          value       :: term(),
+          children = new() :: binomial_heap()
+        }).
+
+-export_type([binomial_heap/0, heap_node/0]).
+-type binomial_heap() :: [ heap_node() ].
+-type heap_node() :: #node{}.
+
+%% eunit_listener callbacks
+-export([
+         init/1,
+         handle_begin/3,
+         handle_end/3,
+         handle_cancel/3,
+         terminate/2,
+         start/0,
+         start/1
+        ]).
+
+%% -- binomial_heap.erl content start --
+
+-record(state, {
+          status = dict:new() :: euf_dict(),
+          failures = []       :: [[pos_integer()]],
+          skips = []          :: [[pos_integer()]],
+          timings = new()     :: binomial_heap(),
+          colored = true      :: boolean(),
+          profile = false     :: boolean()
+        }).
+
+-type euf_dict() :: dict:dict().
+
+-spec new() -> binomial_heap().
+new() ->
+    [].
+
+% Inserts a new pair into the heap (or creates a new heap)
+-spec insert(term(), term()) -> binomial_heap().
+insert(Key,Value) ->
+    insert(Key,Value,[]).
+
+-spec insert(term(), term(), binomial_heap()) -> binomial_heap().
+insert(Key,Value,Forest) ->
+    insTree(#node{key=Key,value=Value},Forest).
+
+% Merges two heaps
+-spec merge(binomial_heap(), binomial_heap()) -> binomial_heap().
+merge(TS1,[]) when is_list(TS1) -> TS1;
+merge([],TS2) when is_list(TS2) -> TS2;
+merge([#node{rank=R1}=T1|TS1]=F1,[#node{rank=R2}=T2|TS2]=F2) ->
+    if
+        R1 < R2 ->
+            [T1 | merge(TS1,F2)];
+        R2 < R1 ->
+            [T2 | merge(F1, TS2)];
+        true ->
+            insTree(link(T1,T2),merge(TS1,TS2))
+    end.
+
+% Deletes the top entry from the heap and returns it
+-spec delete(binomial_heap()) -> {{term(), term()}, binomial_heap()}.
+delete(TS) ->
+    {#node{key=Key,value=Value,children=TS1},TS2} = getMin(TS),
+    {{Key,Value},merge(lists:reverse(TS1),TS2)}.
+
+% Turns the heap into list in heap order
+-spec to_list(binomial_heap()) -> [{term(), term()}].
+to_list([]) -> [];
+to_list(List) when is_list(List) ->
+    to_list([],List).
+to_list(Acc, []) ->
+    lists:reverse(Acc);
+to_list(Acc,Forest) ->
+    {Next, Trees} = delete(Forest),
+    to_list([Next|Acc], Trees).
+
+% Take N elements from the top of the heap
+-spec take(non_neg_integer(), binomial_heap()) -> [{term(), term()}].
+take(N,Trees) when is_integer(N), is_list(Trees) ->
+    take(N,Trees,[]).
+take(0,_Trees,Acc) ->
+    lists:reverse(Acc);
+take(_N,[],Acc)->
+    lists:reverse(Acc);
+take(N,Trees,Acc) ->
+    {Top,T2} = delete(Trees),
+    take(N-1,T2,[Top|Acc]).
+
+% Get an estimate of the size based on the binomial property
+-spec size(binomial_heap()) -> non_neg_integer().
+size(Forest) ->
+    erlang:trunc(lists:sum([math:pow(2,R) || #node{rank=R} <- Forest])).
+
+%% Private API
+-spec link(heap_node(), heap_node()) -> heap_node().
+link(#node{rank=R,key=X1,children=C1}=T1,#node{key=X2,children=C2}=T2) ->
+    case X1 < X2 of
+        true ->
+            T1#node{rank=R+1,children=[T2|C1]};
+        _ ->
+            T2#node{rank=R+1,children=[T1|C2]}
+    end.
+
+insTree(Tree, []) ->
+    [Tree];
+insTree(#node{rank=R1}=T1, [#node{rank=R2}=T2|Rest] = TS) ->
+    case R1 < R2 of
+        true ->
+            [T1|TS];
+        _ ->
+            insTree(link(T1,T2),Rest)
+    end.
+
+getMin([T]) ->
+    {T,[]};
+getMin([#node{key=K} = T|TS]) ->
+    {#node{key=K1} = T1,TS1} = getMin(TS),
+    case K < K1 of
+        true -> {T,TS};
+        _ -> {T1,[T|TS1]}
+    end.
+
+%% -- binomial_heap.erl content end --
+
+%% Startup
+start() ->
+    start([]).
+
+start(Options) ->
+    eunit_listener:start(?MODULE, Options).
+
+%%------------------------------------------
+%% eunit_listener callbacks
+%%------------------------------------------
+init(Options) ->
+    #state{colored=proplists:get_bool(colored, Options),
+           profile=proplists:get_bool(profile, Options)}.
+
+handle_begin(group, Data, St) ->
+    GID = proplists:get_value(id, Data),
+    Dict = St#state.status,
+    St#state{status=dict:store(GID, orddict:from_list([{type, group}|Data]), Dict)};
+handle_begin(test, Data, St) ->
+    TID = proplists:get_value(id, Data),
+    Dict = St#state.status,
+    St#state{status=dict:store(TID, orddict:from_list([{type, test}|Data]), Dict)}.
+
+handle_end(group, Data, St) ->
+    St#state{status=merge_on_end(Data, St#state.status)};
+handle_end(test, Data, St) ->
+    NewStatus = merge_on_end(Data, St#state.status),
+    St1 = print_progress(Data, St),
+    St2 = record_timing(Data, St1),
+    St2#state{status=NewStatus}.
+
+handle_cancel(_, Data, #state{status=Status, skips=Skips}=St) ->
+    Status1 = merge_on_end(Data, Status),
+    ID = proplists:get_value(id, Data),
+    St#state{status=Status1, skips=[ID|Skips]}.
+
+terminate({ok, Data}, St) ->
+    print_failures(St),
+    print_pending(St),
+    print_profile(St),
+    print_timing(St),
+    print_results(Data, St);
+terminate({error, Reason}, St) ->
+    io:nl(), io:nl(),
+    print_colored(io_lib:format("Eunit failed: ~25p~n", [Reason]), ?RED, St),
+    sync_end(error).
+
+sync_end(Result) ->
+    receive
+        {stop, Reference, ReplyTo} ->
+            ReplyTo ! {result, Reference, Result},
+            ok
+    end.
+
+%%------------------------------------------
+%% Print and collect information during run
+%%------------------------------------------
+print_progress(Data, St) ->
+    TID = proplists:get_value(id, Data),
+    case proplists:get_value(status, Data) of
+        ok ->
+            print_progress_success(St),
+            St;
+        {skipped, _Reason} ->
+            print_progress_skipped(St),
+            St#state{skips=[TID|St#state.skips]};
+        {error, Exception} ->
+            print_progress_failed(Exception, St),
+            St#state{failures=[TID|St#state.failures]}
+    end.
+
+record_timing(Data, State=#state{timings=T, profile=true}) ->
+    TID = proplists:get_value(id, Data),
+    case lists:keyfind(time, 1, Data) of
+        {time, Int} ->
+            %% It's a min-heap, so we insert negative numbers instead
+            %% of the actuals and normalize when we report on them.
+            T1 = insert(-Int, TID, T),
+            State#state{timings=T1};
+        false ->
+            State
+    end;
+record_timing(_Data, State) ->
+    State.
+
+print_progress_success(St) ->
+    print_colored(".", ?GREEN, St).
+
+print_progress_skipped(St) ->
+    print_colored("*", ?YELLOW, St).
+
+print_progress_failed(_Exc, St) ->
+    print_colored("F", ?RED, St).
+
+merge_on_end(Data, Dict) ->
+    ID = proplists:get_value(id, Data),
+    dict:update(ID,
+                fun(Old) ->
+                        orddict:merge(fun merge_data/3, Old, orddict:from_list(Data))
+                end, Dict).
+
+merge_data(_K, undefined, X) -> X;
+merge_data(_K, X, undefined) -> X;
+merge_data(_K, _, X) -> X.
+
+%%------------------------------------------
+%% Print information at end of run
+%%------------------------------------------
+print_failures(#state{failures=[]}) ->
+    ok;
+print_failures(#state{failures=Fails}=State) ->
+    io:nl(),
+    io:fwrite("Failures:~n",[]),
+    lists:foldr(print_failure_fun(State), 1, Fails),
+    ok.
+
+print_failure_fun(#state{status=Status}=State) ->
+    fun(Key, Count) ->
+            TestData = dict:fetch(Key, Status),
+            TestId = format_test_identifier(TestData),
+            io:fwrite("~n  ~p) ~ts~n", [Count, TestId]),
+            print_failure_reason(proplists:get_value(status, TestData),
+                                 proplists:get_value(output, TestData),
+                                 State),
+            io:nl(),
+            Count + 1
+    end.
+
+print_failure_reason({skipped, Reason}, _Output, State) ->
+    print_colored(io_lib:format("     ~ts~n", [format_pending_reason(Reason)]),
+                  ?RED, State);
+print_failure_reason({error, {_Class, Term, Stack}}, Output, State) when
+        is_tuple(Term), tuple_size(Term) == 2, is_list(element(2, Term)) ->
+    print_assertion_failure(Term, Stack, Output, State),
+    print_failure_output(5, Output, State);
+print_failure_reason({error, {error, Error, Stack}}, Output, State) when is_list(Stack) ->
+    print_colored(indent(5, "Failure: ~p~n", [Error]), ?RED, State),
+    print_stack(Stack, State),
+    print_failure_output(5, Output, State);
+print_failure_reason({error, Reason}, Output, State) ->
+    print_colored(indent(5, "Failure: ~p~n", [Reason]), ?RED, State),
+    print_failure_output(5, Output, State).
+
+print_stack(Stack, State) ->
+    print_colored(indent(5, "Stacktrace:~n", []), ?CYAN, State),
+    print_stackframes(Stack, State).
+print_stackframes([{eunit_test, _, _, _} | Stack], State) ->
+    print_stackframes(Stack, State);
+print_stackframes([{eunit_proc, _, _, _} | Stack], State) ->
+    print_stackframes(Stack, State);
+print_stackframes([{Module, Function, _Arity, _Location} | Stack], State) ->
+    print_colored(indent(7, "~p.~p~n", [Module, Function]), ?CYAN, State),
+    print_stackframes(Stack, State);
+print_stackframes([], _State) ->
+    ok.
+
+
+print_failure_output(_, <<>>, _) -> ok;
+print_failure_output(_, undefined, _) -> ok;
+print_failure_output(Indent, Output, State) ->
+    print_colored(indent(Indent, "Output: ~ts", [Output]), ?CYAN, State).
+
+print_assertion_failure({Type, Props}, Stack, Output, State) ->
+    FailureDesc = format_assertion_failure(Type, Props, 5),
+    {M,F,A,Loc} = lists:last(Stack),
+    LocationText = io_lib:format("     %% ~ts:~p:in `~ts`", [proplists:get_value(file, Loc),
+                                                           proplists:get_value(line, Loc),
+                                                           format_function_name(M,F,A)]),
+    print_colored(FailureDesc, ?RED, State),
+    io:nl(),
+    print_colored(LocationText, ?CYAN, State),
+    io:nl(),
+    print_failure_output(5, Output, State),
+    io:nl().
+
+print_pending(#state{skips=[]}) ->
+    ok;
+print_pending(#state{status=Status, skips=Skips}=State) ->
+    io:nl(),
+    io:fwrite("Pending:~n", []),
+    lists:foreach(fun(ID) ->
+                          Info = dict:fetch(ID, Status),
+                          case proplists:get_value(reason, Info) of
+                              undefined ->
+                                  ok;
+                              Reason ->
+                                  print_pending_reason(Reason, Info, State)
+                          end
+                  end, lists:reverse(Skips)),
+    io:nl().
+
+print_pending_reason(Reason0, Data, State) ->
+    Text = case proplists:get_value(type, Data) of
+               group ->
+                   io_lib:format("  ~ts~n", [proplists:get_value(desc, Data)]);
+               test ->
+                   io_lib:format("  ~ts~n", [format_test_identifier(Data)])
+           end,
+    Reason = io_lib:format("    %% ~ts~n", [format_pending_reason(Reason0)]),
+    print_colored(Text, ?YELLOW, State),
+    print_colored(Reason, ?CYAN, State).
+
+print_profile(#state{timings=T, status=Status, profile=true}=State) ->
+    TopN = take(10, T),
+    TopNTime = abs(lists:sum([ Time || {Time, _} <- TopN ])),
+    TLG = dict:fetch([], Status),
+    TotalTime = proplists:get_value(time, TLG),
+    if TotalTime =/= undefined andalso TotalTime > 0 andalso TopN =/= [] ->
+            TopNPct = (TopNTime / TotalTime) * 100,
+            io:nl(), io:nl(),
+            io:fwrite("Top ~p slowest tests (~ts, ~.1f% of total time):", [length(TopN), format_time(TopNTime), TopNPct]),
+            lists:foreach(print_timing_fun(State), TopN),
+            io:nl();
+       true -> ok
+    end;
+print_profile(#state{profile=false}) ->
+    ok.
+
+print_timing(#state{status=Status}) ->
+    TLG = dict:fetch([], Status),
+    Time = proplists:get_value(time, TLG),
+    io:nl(),
+    io:fwrite("Finished in ~ts~n", [format_time(Time)]),
+    ok.
+
+print_results(Data, State) ->
+    Pass = proplists:get_value(pass, Data, 0),
+    Fail = proplists:get_value(fail, Data, 0),
+    Skip = proplists:get_value(skip, Data, 0),
+    Cancel = proplists:get_value(cancel, Data, 0),
+    Total = Pass + Fail + Skip + Cancel,
+    {Color, Result} = if Fail > 0 -> {?RED, error};
+                         Skip > 0; Cancel > 0 -> {?YELLOW, error};
+                         Pass =:= 0 -> {?YELLOW, ok};
+                         true -> {?GREEN, ok}
+                      end,
+    print_results(Color, Total, Fail, Skip, Cancel, State),
+    sync_end(Result).
+
+print_results(Color, 0, _, _, _, State) ->
+    print_colored(Color, "0 tests\n", State);
+print_results(Color, Total, Fail, Skip, Cancel, State) ->
+    SkipText = format_optional_result(Skip, "skipped"),
+    CancelText = format_optional_result(Cancel, "cancelled"),
+    Text = io_lib:format("~p tests, ~p failures~ts~ts~n", [Total, Fail, SkipText, CancelText]),
+    print_colored(Text, Color, State).
+
+print_timing_fun(#state{status=Status}=State) ->
+    fun({Time, Key}) ->
+            TestData = dict:fetch(Key, Status),
+            TestId = format_test_identifier(TestData),
+            io:nl(),
+            io:fwrite("  ~ts~n", [TestId]),
+            print_colored(["    "|format_time(abs(Time))], ?CYAN, State)
+    end.
+
+%%------------------------------------------
+%% Print to the console with the given color
+%% if enabled.
+%%------------------------------------------
+print_colored(Text, Color, #state{colored=true}) ->
+    io:fwrite("~s~ts~s", [Color, Text, ?RESET]);
+print_colored(Text, _Color, #state{colored=false}) ->
+    io:fwrite("~ts", [Text]).
+
+%%------------------------------------------
+%% Generic data formatters
+%%------------------------------------------
+format_function_name(M, F, A) ->
+    io_lib:format("~ts:~ts/~p", [M, F, A]).
+
+format_optional_result(0, _) ->
+    [];
+format_optional_result(Count, Text) ->
+    io_lib:format(", ~p ~ts", [Count, Text]).
+
+format_test_identifier(Data) ->
+    {Mod, Fun, Arity} = proplists:get_value(source, Data),
+    Line = case proplists:get_value(line, Data) of
+               0 -> "";
+               L -> io_lib:format(":~p", [L])
+           end,
+    Desc = case proplists:get_value(desc, Data) of
+               undefined ->  "";
+               DescText -> io_lib:format(": ~ts", [DescText])
+           end,
+    io_lib:format("~ts~ts~ts", [format_function_name(Mod, Fun, Arity), Line, Desc]).
+
+format_time(undefined) ->
+    "? seconds";
+format_time(Time) ->
+    io_lib:format("~.3f seconds", [Time / 1000]).
+
+format_pending_reason({module_not_found, M}) ->
+    io_lib:format("Module '~ts' missing", [M]);
+format_pending_reason({no_such_function, {M,F,A}}) ->
+    io_lib:format("Function ~ts undefined", [format_function_name(M,F,A)]);
+format_pending_reason({exit, Reason}) ->
+    io_lib:format("Related process exited with reason: ~p", [Reason]);
+format_pending_reason(Reason) ->
+    io_lib:format("Unknown error: ~p", [Reason]).
+
+%% @doc Formats all the known eunit assertions, you're on your own if
+%% you make an assertion yourself.
+format_assertion_failure(Type, Props, I) when Type =:= assertion_failed
+                                            ; Type =:= assert ->
+    Keys = proplists:get_keys(Props),
+    HasEUnitProps = ([expression, value] -- Keys) =:= [],
+    HasHamcrestProps = ([expected, actual, matcher] -- Keys) =:= [],
+    if
+        HasEUnitProps ->
+            [indent(I, "Failure: ?assert(~ts)~n", [proplists:get_value(expression, Props)]),
+             indent(I, "  expected: true~n", []),
+             case proplists:get_value(value, Props) of
+                 false ->
+                     indent(I, "       got: false", []);
+                 {not_a_boolean, V} ->
+                     indent(I, "       got: ~p", [V])
+             end];
+        HasHamcrestProps ->
+            [indent(I, "Failure: ?assertThat(~p)~n", [proplists:get_value(matcher, Props)]),
+             indent(I, "  expected: ~p~n", [proplists:get_value(expected, Props)]),
+             indent(I, "       got: ~p", [proplists:get_value(actual, Props)])];
+        true ->
+            [indent(I, "Failure: unknown assert: ~p", [Props])]
+    end;
+
+format_assertion_failure(Type, Props, I) when Type =:= assertMatch_failed
+                                            ; Type =:= assertMatch ->
+    Expr = proplists:get_value(expression, Props),
+    Pattern = proplists:get_value(pattern, Props),
+    Value = proplists:get_value(value, Props),
+    [indent(I, "Failure: ?assertMatch(~ts, ~ts)~n", [Pattern, Expr]),
+     indent(I, "  expected: = ~ts~n", [Pattern]),
+     indent(I, "       got: ~p", [Value])];
+
+format_assertion_failure(Type, Props, I) when Type =:= assertNotMatch_failed
+                                                             ; Type =:= assertNotMatch  ->
+    Expr = proplists:get_value(expression, Props),
+    Pattern = proplists:get_value(pattern, Props),
+    Value = proplists:get_value(value, Props),
+    [indent(I, "Failure: ?assertNotMatch(~ts, ~ts)~n", [Pattern, Expr]),
+     indent(I, "  expected not: = ~ts~n", [Pattern]),
+     indent(I, "           got:   ~p", [Value])];
+
+format_assertion_failure(Type, Props, I) when Type =:= assertEqual_failed
+                                            ; Type =:= assertEqual  ->
+    Expr = proplists:get_value(expression, Props),
+    Expected = proplists:get_value(expected, Props),
+    Value = proplists:get_value(value, Props),
+    [indent(I, "Failure: ?assertEqual(~w, ~ts)~n", [Expected,
+                                                         Expr]),
+     indent(I, "  expected: ~p~n", [Expected]),
+     indent(I, "       got: ~p", [Value])];
+
+format_assertion_failure(Type, Props, I) when Type =:= assertNotEqual_failed
+                                            ; Type =:= assertNotEqual ->
+    Expr = proplists:get_value(expression, Props),
+    Value = proplists:get_value(value, Props),
+    [indent(I, "Failure: ?assertNotEqual(~p, ~ts)~n",
+            [Value, Expr]),
+     indent(I, "  expected not: == ~p~n", [Value]),
+     indent(I, "           got:    ~p", [Value])];
+
+format_assertion_failure(Type, Props, I) when Type =:= assertException_failed
+                                            ; Type =:= assertException ->
+    Expr = proplists:get_value(expression, Props),
+    Pattern = proplists:get_value(pattern, Props),
+    {Class, Term} = extract_exception_pattern(Pattern), % I hate that we have to do this, why not just give DATA
+    [indent(I, "Failure: ?assertException(~ts, ~ts, ~ts)~n", [Class, Term, Expr]),
+     case proplists:is_defined(unexpected_success, Props) of
+         true ->
+             [indent(I, "  expected: exception ~ts but nothing was raised~n", [Pattern]),
+              indent(I, "       got: value ~p", [proplists:get_value(unexpected_success, Props)])];
+         false ->
+             Ex = proplists:get_value(unexpected_exception, Props),
+             [indent(I, "  expected: exception ~ts~n", [Pattern]),
+              indent(I, "       got: exception ~p", [Ex])]
+     end];
+
+format_assertion_failure(Type, Props, I) when Type =:= assertNotException_failed
+                                            ; Type =:= assertNotException ->
+    Expr = proplists:get_value(expression, Props),
+    Pattern = proplists:get_value(pattern, Props),
+    {Class, Term} = extract_exception_pattern(Pattern), % I hate that we have to do this, why not just give DAT
+    Ex = proplists:get_value(unexpected_exception, Props),
+    [indent(I, "Failure: ?assertNotException(~ts, ~ts, ~ts)~n", [Class, Term, Expr]),
+     indent(I, "  expected not: exception ~ts~n", [Pattern]),
+     indent(I, "           got: exception ~p", [Ex])];
+
+format_assertion_failure(Type, Props, I) when Type =:= command_failed
+                                            ; Type =:= command ->
+    Cmd = proplists:get_value(command, Props),
+    Expected = proplists:get_value(expected_status, Props),
+    Status = proplists:get_value(status, Props),
+    [indent(I, "Failure: ?cmdStatus(~p, ~p)~n", [Expected, Cmd]),
+     indent(I, "  expected: status ~p~n", [Expected]),
+     indent(I, "       got: status ~p", [Status])];
+
+format_assertion_failure(Type, Props, I) when Type =:= assertCmd_failed
+                                            ; Type =:= assertCmd ->
+    Cmd = proplists:get_value(command, Props),
+    Expected = proplists:get_value(expected_status, Props),
+    Status = proplists:get_value(status, Props),
+    [indent(I, "Failure: ?assertCmdStatus(~p, ~p)~n", [Expected, Cmd]),
+     indent(I, "  expected: status ~p~n", [Expected]),
+     indent(I, "       got: status ~p", [Status])];
+
+format_assertion_failure(Type, Props, I) when Type =:= assertCmdOutput_failed
+                                            ; Type =:= assertCmdOutput ->
+    Cmd = proplists:get_value(command, Props),
+    Expected = proplists:get_value(expected_output, Props),
+    Output = proplists:get_value(output, Props),
+    [indent(I, "Failure: ?assertCmdOutput(~p, ~p)~n", [Expected, Cmd]),
+     indent(I, "  expected: ~p~n", [Expected]),
+     indent(I, "       got: ~p", [Output])];
+
+format_assertion_failure(Type, Props, I) ->
+    indent(I, "~p", [{Type, Props}]).
+
+indent(I, Fmt, Args) ->
+    io_lib:format("~" ++ integer_to_list(I) ++ "s" ++ Fmt, [" "|Args]).
+
+extract_exception_pattern(Str) ->
+    ["{", Class, Term|_] = re:split(Str, "[, ]{1,2}", [unicode,{return,list}]),
+    {Class, Term}.
diff --git a/test/gleam_stdlib_test.gleam b/test/gleam_stdlib_test.gleam
new file mode 100644
index 0000000..04635a2
--- /dev/null
+++ b/test/gleam_stdlib_test.gleam
@@ -0,0 +1,4 @@
+if erlang {
+  pub external fn main() -> Nil =
+    "gleam_stdlib_test_ffi" "main"
+}
diff --git a/test/gleam_stdlib_test_ffi.erl b/test/gleam_stdlib_test_ffi.erl
new file mode 100644
index 0000000..61c82de
--- /dev/null
+++ b/test/gleam_stdlib_test_ffi.erl
@@ -0,0 +1,22 @@
+-module(gleam_stdlib_test_ffi).
+
+-export([main/0]).
+
+main() ->
+    Options = [
+        no_tty, {report, {eunit_progress, [colored]}}
+    ],
+    Files = filelib:wildcard("test/**/*.{erl,gleam}"),
+    Modules = lists:map(fun filepath_to_module/1, Files),
+    case eunit:test(Modules, Options) of
+        ok -> erlang:halt(0);
+        _ -> erlang:halt(1)
+    end.
+
+filepath_to_module(Path0) ->
+    Path1 = string:replace(Path0, "test/", ""),
+    Path2 = string:replace(Path1, ".erl", ""),
+    Path3 = string:replace(Path2, ".gleam", ""),
+    Path4 = string:replace(Path3, "/", "@", all),
+    Path5 = list_to_binary(Path4),
+    binary_to_atom(Path5).