tests: move t0009-prio-queue.sh to the new unit testing framework

t/t0009-prio-queue.sh along with t/helper/test-prio-queue.c unit
tests Git's implementation of a priority queue. Migrate the
test over to the new unit testing framework to simplify debugging
and reduce test run-time. Refactor the required logic and add
a new test case in addition to porting over the original ones in
shell.

Signed-off-by: Chandra Pratap <chandrapratap3519@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/t/helper/test-prio-queue.c b/t/helper/test-prio-queue.c
deleted file mode 100644
index f0bf255..0000000
--- a/t/helper/test-prio-queue.c
+++ /dev/null
@@ -1,51 +0,0 @@
-#include "test-tool.h"
-#include "prio-queue.h"
-
-static int intcmp(const void *va, const void *vb, void *data UNUSED)
-{
-	const int *a = va, *b = vb;
-	return *a - *b;
-}
-
-static void show(int *v)
-{
-	if (!v)
-		printf("NULL\n");
-	else
-		printf("%d\n", *v);
-	free(v);
-}
-
-int cmd__prio_queue(int argc UNUSED, const char **argv)
-{
-	struct prio_queue pq = { intcmp };
-
-	while (*++argv) {
-		if (!strcmp(*argv, "get")) {
-			void *peek = prio_queue_peek(&pq);
-			void *get = prio_queue_get(&pq);
-			if (peek != get)
-				BUG("peek and get results do not match");
-			show(get);
-		} else if (!strcmp(*argv, "dump")) {
-			void *peek;
-			void *get;
-			while ((peek = prio_queue_peek(&pq))) {
-				get = prio_queue_get(&pq);
-				if (peek != get)
-					BUG("peek and get results do not match");
-				show(get);
-			}
-		} else if (!strcmp(*argv, "stack")) {
-			pq.compare = NULL;
-		} else {
-			int *v = xmalloc(sizeof(*v));
-			*v = atoi(*argv);
-			prio_queue_put(&pq, v);
-		}
-	}
-
-	clear_prio_queue(&pq);
-
-	return 0;
-}
diff --git a/t/helper/test-tool.c b/t/helper/test-tool.c
index 37ba996..ccc1d36 100644
--- a/t/helper/test-tool.c
+++ b/t/helper/test-tool.c
@@ -56,7 +56,6 @@ static struct test_cmd cmds[] = {
 	{ "path-utils", cmd__path_utils },
 	{ "pcre2-config", cmd__pcre2_config },
 	{ "pkt-line", cmd__pkt_line },
-	{ "prio-queue", cmd__prio_queue },
 	{ "proc-receive", cmd__proc_receive },
 	{ "progress", cmd__progress },
 	{ "reach", cmd__reach },
diff --git a/t/helper/test-tool.h b/t/helper/test-tool.h
index 8a1a7c6..8a8926f 100644
--- a/t/helper/test-tool.h
+++ b/t/helper/test-tool.h
@@ -49,7 +49,6 @@ int cmd__partial_clone(int argc, const char **argv);
 int cmd__path_utils(int argc, const char **argv);
 int cmd__pcre2_config(int argc, const char **argv);
 int cmd__pkt_line(int argc, const char **argv);
-int cmd__prio_queue(int argc, const char **argv);
 int cmd__proc_receive(int argc, const char **argv);
 int cmd__progress(int argc, const char **argv);
 int cmd__reach(int argc, const char **argv);
diff --git a/t/t0009-prio-queue.sh b/t/t0009-prio-queue.sh
deleted file mode 100755
index eea9910..0000000
--- a/t/t0009-prio-queue.sh
+++ /dev/null
@@ -1,66 +0,0 @@
-#!/bin/sh
-
-test_description='basic tests for priority queue implementation'
-
-TEST_PASSES_SANITIZE_LEAK=true
-. ./test-lib.sh
-
-cat >expect <<'EOF'
-1
-2
-3
-4
-5
-5
-6
-7
-8
-9
-10
-EOF
-test_expect_success 'basic ordering' '
-	test-tool prio-queue 2 6 3 10 9 5 7 4 5 8 1 dump >actual &&
-	test_cmp expect actual
-'
-
-cat >expect <<'EOF'
-2
-3
-4
-1
-5
-6
-EOF
-test_expect_success 'mixed put and get' '
-	test-tool prio-queue 6 2 4 get 5 3 get get 1 dump >actual &&
-	test_cmp expect actual
-'
-
-cat >expect <<'EOF'
-1
-2
-NULL
-1
-2
-NULL
-EOF
-test_expect_success 'notice empty queue' '
-	test-tool prio-queue 1 2 get get get 1 2 get get get >actual &&
-	test_cmp expect actual
-'
-
-cat >expect <<'EOF'
-3
-2
-6
-4
-5
-1
-8
-EOF
-test_expect_success 'stack order' '
-	test-tool prio-queue stack 8 1 5 4 6 2 3 dump >actual &&
-	test_cmp expect actual
-'
-
-test_done
diff --git a/t/unit-tests/t-prio-queue.c b/t/unit-tests/t-prio-queue.c
new file mode 100644
index 0000000..d78b002
--- /dev/null
+++ b/t/unit-tests/t-prio-queue.c
@@ -0,0 +1,98 @@
+#include "test-lib.h"
+#include "prio-queue.h"
+
+static int intcmp(const void *va, const void *vb, void *data UNUSED)
+{
+	const int *a = va, *b = vb;
+	return *a - *b;
+}
+
+
+#define MISSING  -1
+#define DUMP	 -2
+#define STACK	 -3
+#define GET	 -4
+#define REVERSE  -5
+
+static int show(int *v)
+{
+	return v ? *v : MISSING;
+}
+
+static void test_prio_queue(int *input, int *result, size_t input_size)
+{
+	struct prio_queue pq = { intcmp };
+
+	for (int i = 0, j = 0; i < input_size; i++) {
+		void *peek, *get;
+		switch(input[i]) {
+		case GET:
+			peek = prio_queue_peek(&pq);
+			get = prio_queue_get(&pq);
+			if (!check(peek == get))
+				return;
+			if(!check_int(result[j++], ==, show(get)))
+				test_msg("failed at result[] index %d", j-1);
+			break;
+		case DUMP:
+			while ((peek = prio_queue_peek(&pq))) {
+				get = prio_queue_get(&pq);
+				if (!check(peek == get))
+					return;
+				if(!check_int(result[j++], ==, show(get)))
+					test_msg("failed at result[] index %d", j-1);
+			}
+			break;
+		case STACK:
+			pq.compare = NULL;
+			break;
+		case REVERSE:
+			prio_queue_reverse(&pq);
+			break;
+		default:
+			prio_queue_put(&pq, &input[i]);
+			break;
+		}
+	}
+	clear_prio_queue(&pq);
+}
+
+#define BASIC_INPUT 2, 6, 3, 10, 9, 5, 7, 4, 5, 8, 1, DUMP
+#define BASIC_RESULT 1, 2, 3, 4, 5, 5, 6, 7, 8, 9, 10
+
+#define MIXED_PUT_GET_INPUT 6, 2, 4, GET, 5, 3, GET, GET, 1, DUMP
+#define MIXED_PUT_GET_RESULT 2, 3, 4, 1, 5, 6
+
+#define EMPTY_QUEUE_INPUT 1, 2, GET, GET, GET, 1, 2, GET, GET, GET
+#define EMPTY_QUEUE_RESULT 1, 2, MISSING, 1, 2, MISSING
+
+#define STACK_INPUT STACK, 8, 1, 5, 4, 6, 2, 3, DUMP
+#define STACK_RESULT 3, 2, 6, 4, 5, 1, 8
+
+#define REVERSE_STACK_INPUT STACK, 1, 2, 3, 4, 5, 6, REVERSE, DUMP
+#define REVERSE_STACK_RESULT 1, 2, 3, 4, 5, 6
+
+#define TEST_INPUT(INPUT, RESULT, name)			\
+  static void test_##name(void)				\
+{								\
+	int input[] = {INPUT};					\
+	int result[] = {RESULT};				\
+	test_prio_queue(input, result, ARRAY_SIZE(input));	\
+}
+
+TEST_INPUT(BASIC_INPUT, BASIC_RESULT, basic)
+TEST_INPUT(MIXED_PUT_GET_INPUT, MIXED_PUT_GET_RESULT, mixed)
+TEST_INPUT(EMPTY_QUEUE_INPUT, EMPTY_QUEUE_RESULT, empty)
+TEST_INPUT(STACK_INPUT, STACK_RESULT, stack)
+TEST_INPUT(REVERSE_STACK_INPUT, REVERSE_STACK_RESULT, reverse)
+
+int cmd_main(int argc, const char **argv)
+{
+	TEST(test_basic(), "prio-queue works for basic input");
+	TEST(test_mixed(), "prio-queue works for mixed put & get commands");
+	TEST(test_empty(), "prio-queue works when queue is empty");
+	TEST(test_stack(), "prio-queue works when used as a LIFO stack");
+	TEST(test_reverse(), "prio-queue works when LIFO stack is reversed");
+
+	return test_done();
+}