Made grep version command's grep POSIX

src/ec_git_vsn.erl

@@ -86,7 +86,10 @@ get_patch_count(RawRef) ->
 
 -spec parse_tags(t()) -> {string()|undefined, ec_semver:version_string()}.
 parse_tags({Prefix}) ->
-    first_valid_tag(os:cmd("git log --oneline --decorate  | fgrep \"tag: \" -1000"), Prefix).
+    first_valid_tag(os:cmd("git log --oneline --decorate  | grep -F \"tag: \""), Prefix).
+    %% TODO: The following command sould be able to get the version
+    %% number directly, without a re:run. Should be checked for POSIX
+    %% "git log --oneline --decorate | grep -F \"tag: \" --color=never | head -n 1 | sed  \"s/.*tag: " ++ Prefix ++ "\([^,)]*\).*/\1/\"".
 
 -spec first_valid_tag(string(), string()) -> {string()|undefined, ec_semver:version_string()}.
 first_valid_tag(Line, Prefix) ->

test/ec_git_vsn_tests.erl

@@ -0,0 +1,15 @@
+-module(ec_git_vsn_tests).
+-include_lib("eunit/include/eunit.hrl").
+-compile([export_all]).
+
+
+%% Hi! This test only works because you've cloned this repo out of git
+%% AND we're tagging this repo with a "v" prefix. Hey, it's better
+%% than nothing.
+vsn_grep_test() ->
+    {ok, VSN} = ec_git_vsn:vsn({"v"}),
+
+    [$v|OtherVSN] = os:cmd("git tag | xargs -I@ git log --format=format:\"%ai @%n\" -1 @ | sort -r | awk '{print $4}' | head -n 1"),
+
+    ?assertEqual(OtherVSN, VSN ++ "\n"),
+    ok.