t-reftable-pq: add tests for merged_iter_pqueue_top()

merged_iter_pqueue_top() as defined by reftable/pq.{c, h} returns
the element at the top of a priority-queue's heap without removing
it. Since there are no tests for this function in the existing
setup, add tests for the same.

Mentored-by: Patrick Steinhardt <ps@pks.im>
Mentored-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Chandra Pratap <chandrapratap3519@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/t/unit-tests/t-reftable-pq.c b/t/unit-tests/t-reftable-pq.c
index 70ff89507d124fa0a8185dde9747156a067f0991..039bd0f1f9893f1a869024ca79324c8c7dd56ef4 100644 (file)
--- a/t/unit-tests/t-reftable-pq.c
+++ b/t/unit-tests/t-reftable-pq.c
@@ -18,6 +18,11 @@ static void merged_iter_pqueue_check(const struct merged_iter_pqueue *pq)
        }
 }
 
+static int pq_entry_equal(struct pq_entry *a, struct pq_entry *b)
+{
+       return !reftable_record_cmp(a->rec, b->rec) && (a->index == b->index);
+}
+
 static void t_pq_record(void)
 {
        struct merged_iter_pqueue pq = { 0 };
@@ -42,9 +47,11 @@ static void t_pq_record(void)
        } while (i != 1);
 
        while (!merged_iter_pqueue_is_empty(pq)) {
+               struct pq_entry top = merged_iter_pqueue_top(pq);
                struct pq_entry e = merged_iter_pqueue_remove(&pq);
                merged_iter_pqueue_check(&pq);
 
+               check(pq_entry_equal(&top, &e));
                check(reftable_record_type(e.rec) == BLOCK_TYPE_REF);
                if (last)
                        check_int(strcmp(last, e.rec->u.ref.refname), <, 0);
@@ -81,9 +88,11 @@ static void t_pq_index(void)
        } while (i != 1);
 
        for (i = N - 1; i > 0; i--) {
+               struct pq_entry top = merged_iter_pqueue_top(pq);
                struct pq_entry e = merged_iter_pqueue_remove(&pq);
                merged_iter_pqueue_check(&pq);
 
+               check(pq_entry_equal(&top, &e));
                check(reftable_record_type(e.rec) == BLOCK_TYPE_REF);
                check_int(e.index, ==, i);
                if (last)
@@ -94,10 +103,50 @@ static void t_pq_index(void)
        merged_iter_pqueue_release(&pq);
 }
 
+static void t_merged_iter_pqueue_top(void)
+{
+       struct merged_iter_pqueue pq = { 0 };
+       struct reftable_record recs[13];
+       size_t N = ARRAY_SIZE(recs), i;
+
+       for (i = 0; i < N; i++) {
+               reftable_record_init(&recs[i], BLOCK_TYPE_REF);
+               recs[i].u.ref.refname = (char *) "refs/heads/master";
+       }
+
+       i = 1;
+       do {
+               struct pq_entry e = {
+                       .rec = &recs[i],
+                       .index = i,
+               };
+
+               merged_iter_pqueue_add(&pq, &e);
+               merged_iter_pqueue_check(&pq);
+               i = (i * 7) % N;
+       } while (i != 1);
+
+       for (i = N - 1; i > 0; i--) {
+               struct pq_entry top = merged_iter_pqueue_top(pq);
+               struct pq_entry e = merged_iter_pqueue_remove(&pq);
+
+               merged_iter_pqueue_check(&pq);
+               check(pq_entry_equal(&top, &e));
+               check(reftable_record_equal(top.rec, &recs[i], GIT_SHA1_RAWSZ));
+               for (size_t j = 0; i < pq.len; j++) {
+                       check(pq_less(&top, &pq.heap[j]));
+                       check_int(top.index, >, j);
+               }
+       }
+
+       merged_iter_pqueue_release(&pq);
+}
+
 int cmd_main(int argc, const char *argv[])
 {
        TEST(t_pq_record(), "pq works with record-based comparison");
        TEST(t_pq_index(), "pq works with index-based comparison");
+       TEST(t_merged_iter_pqueue_top(), "merged_iter_pqueue_top works");
 
        return test_done();
 }