[PATCH v3 6/7] t-reftable-pq: add test for index based comparison

[Chandra Pratap <chandrapratap3519@gmail.com>]

When comparing two entries, the priority queue as defined by
reftable/pq.{c, h} first compares the entries on the basis of
their ref-record's keys. If the keys turn out to be equal, the
comparison is then made on the basis of their update indices
(which are never equal).

In the current testing setup, only the case for comparison on
the basis of ref-record's keys is exercised. Add a test for
index-based comparison as well. Rename the existing test to
reflect its nature of only testing record-based comparison.

Mentored-by: Patrick Steinhardt <ps@pks.im>
Mentored-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Chandra Pratap <chandrapratap3519@gmail.com>
---
 t/unit-tests/t-reftable-pq.c | 43 ++++++++++++++++++++++++++++++++++--
 1 file changed, 41 insertions(+), 2 deletions(-)

diff --git a/t/unit-tests/t-reftable-pq.c b/t/unit-tests/t-reftable-pq.c
index 774c4194e5..e114a8cb0f 100644
--- a/t/unit-tests/t-reftable-pq.c
+++ b/t/unit-tests/t-reftable-pq.c
@@ -18,7 +18,7 @@ static void merged_iter_pqueue_check(const struct merged_iter_pqueue *pq)
 	}
 }
 
-static void test_pq(void)
+static void test_pq_record(void)
 {
 	struct merged_iter_pqueue pq = { 0 };
 	struct reftable_record recs[54];
@@ -59,9 +59,48 @@ static void test_pq(void)
 	merged_iter_pqueue_release(&pq);
 }
 
+static void test_pq_index(void)
+{
+	struct merged_iter_pqueue pq = { 0 };
+	struct reftable_record recs[14];
+	char *last = NULL;
+	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 = xstrdup("refs/heads/master");
+	}
+
+	for (i = 0; i < N; i++) {
+		struct pq_entry e = {
+			.rec = &recs[i],
+			.index = i,
+		};
+
+		merged_iter_pqueue_add(&pq, &e);
+		merged_iter_pqueue_check(&pq);
+	}
+
+	for (i = N - 1; !merged_iter_pqueue_is_empty(pq); i--) {
+		struct pq_entry e = merged_iter_pqueue_remove(&pq);
+		merged_iter_pqueue_check(&pq);
+
+		check(reftable_record_type(e.rec) == BLOCK_TYPE_REF);
+		check_int(e.index, ==, i);
+		if (last)
+			check_str(last, e.rec->u.ref.refname);
+		last = e.rec->u.ref.refname;
+	}
+
+	for (i = 0; i < N; i++)
+		reftable_record_release(&recs[i]);
+	merged_iter_pqueue_release(&pq);
+}
+
 int cmd_main(int argc, const char *argv[])
 {
-	TEST(test_pq(), "pq works");
+	TEST(test_pq_record(), "pq works with record-based comparison");
+	TEST(test_pq_index(), "pq works with index-based comparison");
 
 	return test_done();
 }
-- 
2.45.2.404.g9eaef5822c