From 588337e78bfd093a2003929c2bbc1d824a08fc76 Mon Sep 17 00:00:00 2001
From: Dave Smith <dizzyd@dizzyd.com>
Date: Wed, 9 Dec 2009 22:00:28 -0700
Subject: [PATCH] Add support for coverage generation

---
 src/rebar_eunit.erl | 105 +++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 103 insertions(+), 2 deletions(-)

diff --git a/src/rebar_eunit.erl b/src/rebar_eunit.erl
index 69f8a0a..a75a8a0 100644
--- a/src/rebar_eunit.erl
+++ b/src/rebar_eunit.erl
@@ -50,9 +50,18 @@ eunit(Config, File) ->
     ok = filelib:ensure_dir(?EUNIT_DIR ++ "/foo"),
 
     %% Compile all erlang from src/ into ?EUNIT_DIR
-    rebar_erlc_compiler:do_compile(Config, "src/*.erl", ?EUNIT_DIR, ".erl", ".beam", fun compile_erl/2,
+    rebar_erlc_compiler:do_compile(Config, "src/*.erl", ?EUNIT_DIR, ".erl", ".beam",
+                                   fun compile_erl/2,
                                    rebar_config:get_list(Config, erl_first_files, [])),
 
+    %% Build a list of all the .beams in ?EUNIT_DIR -- use this for cover
+    %% and eunit testing. Normally you can just tell cover and/or eunit to
+    %% scan the directory for you, but eunit does a code:purge in conjunction
+    %% with that scan and causes any cover compilation info to be lost. So,
+    %% we do it by hand. :(
+    Modules = [list_to_atom(filename:basename(N, ".beam")) ||
+                  N <- filelib:wildcard("*.beam", "ebin")],
+
     %% TODO: If there are other wildcards specified in eunit_sources, compile them
 
     %% Save current code path and then prefix ?EUNIT_DIR on it so that our modules
@@ -68,9 +77,22 @@ eunit(Config, File) ->
             BaseOpts = []
     end,
 
+    %% If cover support is requested, set it up
+    case rebar_config:get(Config, cover_enabled, false) of
+        true ->
+            cover_init(Config);
+        _ ->
+            ok
+    end,
+
     %% Run eunit
     EunitOpts = BaseOpts ++ rebar_config:get_list(Config, eunit_opts, []),
-    case catch(eunit:test({dir, ?EUNIT_DIR}, EunitOpts)) of
+    EunitResult = (catch eunit:test(Modules, EunitOpts)),
+
+    %% Analyze cover modules
+    cover_analyze(Config, cover:modules()),
+
+    case EunitResult of
         ok ->
             ok;
         _ ->
@@ -78,6 +100,7 @@ eunit(Config, File) ->
             ?FAIL
     end,
 
+
     %% Restore code path
     true = code:set_path(InitCodePath),
     ok.
@@ -125,4 +148,82 @@ is_quickcheck_avail() ->
             IsAvail
     end.
                           
+cover_init(Config) ->
+    %% Make sure any previous runs of cover don't unduly influence
+    cover:reset(),
 
+    ?INFO("Cover compiling ~s\n", [rebar_utils:get_cwd()]),
+    
+    case cover:compile_beam_directory(?EUNIT_DIR) of
+        {error, Reason2} ->
+            ?ERROR("Cover compilation failed: ~p\n", [Reason2]),
+            ?FAIL;
+        Modules ->
+            %% It's not an error for cover compilation to fail partially, but we do want
+            %% to warn about them
+            [?CONSOLE("Cover compilation warning: ~p", [Desc]) || {error, Desc} <- Modules],
+
+            %% Identify the modules that were compiled successfully
+            case [ M || {ok, M} <- Modules] of
+                [] ->
+                    %% No modules compiled successfully...fail
+                    ?ERROR("Cover failed to compile any modules; aborting.\n", []),
+                    ?FAIL;
+                _ ->
+                    %% At least one module compiled successfully
+                    ok
+            end
+    end.
+
+cover_analyze(Config, []) ->
+    ok;
+cover_analyze(Config, Modules) ->    
+    %% Generate coverage info for all the cover-compiled modules 
+    Coverage = [cover_analyze_mod(M) || M <- Modules],
+
+    %% Write index of coverage info
+    cover_write_index(lists:sort(Coverage)),
+
+    %% Write coverage details for each file
+    [{ok, _} = cover:analyze_to_file(M, cover_file(M), [html]) || {M, _, _} <- Coverage],
+
+    Index = filename:join([rebar_utils:get_cwd(), ?EUNIT_DIR, "index.html"]),
+    ?CONSOLE("Cover analysis: ~s\n", [Index]).
+    
+
+cover_analyze_mod(Module) ->
+    case cover:analyze(Module, coverage, module) of
+        {ok, {Module, {Covered, NotCovered}}} ->
+            {Module, Covered, NotCovered};
+        {error, Reason} ->
+            ?ERROR("Cover analyze failed for ~p: ~p ~p\n",
+                   [Module, Reason, code:which(Module)]),
+            {0,0}
+    end.
+
+cover_write_index(Coverage) ->
+    %% Calculate total coverage %
+    {Covered, NotCovered} = lists:foldl(fun({Mod, C, N}, {CAcc, NAcc}) ->
+                                                {CAcc + C, NAcc + N}
+                                        end, {0, 0}, Coverage),
+    TotalCoverage = percentage(Covered, NotCovered),
+
+    %% Write the report
+    {ok, F} = file:open(filename:join([?EUNIT_DIR, "index.html"]), [write]),
+    ok = file:write(F, "<html><head><title>Coverage Summary</title></head>\n"
+                    "<body><h1>Coverage Summary</h1>\n"),
+    ok = file:write(F, ?FMT("<h3>Total: ~w%</h3>\n", [TotalCoverage])),
+    ok = file:write(F, "<table><tr><th>Module</th><th>Coverage %</th></tr>\n"),
+
+    [ok = file:write(F, ?FMT("<tr><td><a href='~s.COVER.html'>~s</a></td><td>~w%</td>\n",
+                             [Module, Module, percentage(Cov, NotCov)])) ||
+        {Module, Cov, NotCov} <- Coverage],
+    ok = file:write(F, "</table></body></html>"),
+    file:close(F).
+
+cover_file(Module) ->    
+    filename:join([?EUNIT_DIR, atom_to_list(Module) ++ ".COVER.html"]).
+    
+    
+percentage(Cov, NotCov) ->
+    trunc((Cov / (Cov + NotCov)) * 100).