Hack on top of swipl library(test_cover) for more granular coverage

coverage.pl

% -*- mode: Prolog -*-

/*
  TODO: generalize this code to work in any file (currently, file name is hard-coded)

  This code depends on a modification to ~/src/swipl-devel/packages/plunit/test_cover.pl:

$ git diff
diff --git a/test_cover.pl b/test_cover.pl
index 5290499..24d8874 100644
--- a/test_cover.pl
+++ b/test_cover.pl
@@ -170,9 +170,11 @@ assert_exited(Cl) :-
 %   Restore state and collect failed and succeeded clauses.

 covered(Succeeded, Failed) :-
+    % findall(Cl, (entered(Cl), \+exited(Cl)), Failed0),
+    % findall(Cl, retract(exited(Cl)), Succeeded0),
+    % retractall(entered(Cl)),
     findall(Cl, (entered(Cl), \+exited(Cl)), Failed0),
-    findall(Cl, retract(exited(Cl)), Succeeded0),
-    retractall(entered(Cl)),
+    findall(Cl, exited(Cl), Succeeded0),
     sort(Failed0, Failed),
     sort(Succeeded0, Succeeded).

*/

/* To run this:

[test_read].
['../test_protobufs'].
show_coverage(run_tests).
my_coverage.
setof(Line, not_covered(Line), Lines), maplist(writeln, Lines).

*/

:- use_module(library(prolog_code), [pi_head/2]).

my_coverage :-
    retractall(covered(_Module, _File, _Pred, _Line)),
    my_coverage(Srcs),
    maplist(assertmy_coverage, Srcs).

my_coverage(Srcs) :-
    prolog_cover:covered(Succeeded,_),
    % length(Succeeded, Len),
    maplist(src, Succeeded, Srcs0),
    sort(Srcs0, Srcs).

src(Clause, covered(Module,File,Pred,Line)) :-
    clause_property(Clause, file(File)),
    clause_property(Clause, module(Module)),
    clause_property(Clause, predicate(Pred0)),
    pi_head(Pred0, Pred),
    clause_property(Clause, line_count(Line)).

lines(Lines) :-
    File = '/home/peter/src/swipl-devel/build/home/library/protobufs.pl',
    setof(Line-Pred, covered(protobufs, File, Pred, Line), Lines0),
    keysort(Lines0, Lines).

not_covered(Line-P) :-
    % TODO: current_predicate(_, protobufs:P) - doesn't need pi_head
    current_predicate(protobufs:P0),
    pi_head(P0, P),
    predicate_property(protobufs:P, file('/home/peter/src/swipl-devel/build/home/library/protobufs.pl')),
    predicate_property(protobufs:P, line_count(Line)),
    \+ covered(protobufs, _, protobufs:P, Line).

print_lines :-
    lines(Lines),
    length(Lines, Len),
    writeln(length:Len),
    maplist(writeln, Lines).