diff --git a/Makefile b/Makefile
index 312d95084c1..d5e48e656b3 100644
--- a/Makefile
+++ b/Makefile
@@ -828,7 +828,6 @@ TEST_BUILTINS_OBJS += test-partial-clone.o
 TEST_BUILTINS_OBJS += test-path-utils.o
 TEST_BUILTINS_OBJS += test-pcre2-config.o
 TEST_BUILTINS_OBJS += test-pkt-line.o
-TEST_BUILTINS_OBJS += test-prio-queue.o
 TEST_BUILTINS_OBJS += test-proc-receive.o
 TEST_BUILTINS_OBJS += test-progress.o
 TEST_BUILTINS_OBJS += test-reach.o
@@ -1340,6 +1339,7 @@ THIRD_PARTY_SOURCES += sha1dc/%
 
 UNIT_TEST_PROGRAMS += t-basic
 UNIT_TEST_PROGRAMS += t-strbuf
+UNIT_TEST_PROGRAMS += t-prio-queue
 UNIT_TEST_PROGS = $(patsubst %,$(UNIT_TEST_BIN)/%$X,$(UNIT_TEST_PROGRAMS))
 UNIT_TEST_OBJS = $(patsubst %,$(UNIT_TEST_DIR)/%.o,$(UNIT_TEST_PROGRAMS))
 UNIT_TEST_OBJS += $(UNIT_TEST_DIR)/test-lib.o
diff --git a/t/helper/test-prio-queue.c b/t/helper/test-prio-queue.c
deleted file mode 100644
index f0bf255f5f0..00000000000
--- 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 876cd2dc313..5f591b9718f 100644
--- a/t/helper/test-tool.c
+++ b/t/helper/test-tool.c
@@ -57,7 +57,6 @@ 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 70dd4eba119..b921138d8ec 100644
--- a/t/helper/test-tool.h
+++ b/t/helper/test-tool.h
@@ -50,7 +50,6 @@ 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 eea99107a48..00000000000
--- 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 00000000000..07b112f5894
--- /dev/null
+++ b/t/unit-tests/t-prio-queue.c
@@ -0,0 +1,99 @@
+#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;
+}
+
+static int show(int *v)
+{
+	int ret = -1;
+	if (v)
+		ret = *v;
+	free(v);
+	return ret;
+}
+
+static int test_prio_queue(const char **input, int *result)
+{
+	struct prio_queue pq = { intcmp };
+	int i = 0;
+
+	while (*input) {
+		if (!strcmp(*input, "get")) {
+			void *peek = prio_queue_peek(&pq);
+			void *get = prio_queue_get(&pq);
+			if (peek != get)
+				BUG("peek and get results do not match");
+			result[i++] = show(get);
+		} else if (!strcmp(*input, "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");
+				result[i++] = show(get);
+			}
+		} else if (!strcmp(*input, "stack")) {
+			pq.compare = NULL;
+		} else if (!strcmp(*input, "reverse")) {
+			prio_queue_reverse(&pq);
+		} else {
+			int *v = xmalloc(sizeof(*v));
+			*v = atoi(*input);
+			prio_queue_put(&pq, v);
+		}
+		input++;
+	}
+
+	clear_prio_queue(&pq);
+
+	return 0;
+}
+
+#define INPUT_SIZE 6
+
+#define BASIC_INPUT "1", "2", "3", "4", "5", "5", "dump"
+#define BASIC_EXPECTED 1, 2, 3, 4, 5, 5
+
+#define MIXED_PUT_GET_INPUT "6", "2", "4", "get", "5", "3", "get", "get", "1", "dump"
+#define MIXED_PUT_GET_EXPECTED 2, 3, 4, 1, 5, 6
+
+#define EMPTY_QUEUE_INPUT "1", "2", "get", "get", "get", "1", "2", "get", "get", "get"
+#define EMPTY_QUEUE_EXPECTED 1, 2, -1, 1, 2, -1
+
+#define STACK_INPUT "stack", "1", "5", "4", "6", "2", "3", "dump"
+#define STACK_EXPECTED 3, 2, 6, 4, 5, 1
+
+#define REVERSE_STACK_INPUT "stack", "1", "2", "3", "4", "5", "6", "reverse", "dump"
+#define REVERSE_STACK_EXPECTED 1, 2, 3, 4, 5, 6
+
+#define TEST_INPUT(INPUT, EXPECTED, name)			\
+  static void test_##name(void)					\
+{								\
+	const char *input[] = {INPUT};				\
+	int expected[] = {EXPECTED};				\
+	int result[INPUT_SIZE];					\
+	test_prio_queue(input, result);				\
+	check(!memcmp(expected, result, sizeof(expected)));	\
+}
+
+TEST_INPUT(BASIC_INPUT, BASIC_EXPECTED, basic)
+TEST_INPUT(MIXED_PUT_GET_INPUT, MIXED_PUT_GET_EXPECTED, mixed)
+TEST_INPUT(EMPTY_QUEUE_INPUT, EMPTY_QUEUE_EXPECTED, empty)
+TEST_INPUT(STACK_INPUT, STACK_EXPECTED, stack)
+TEST_INPUT(REVERSE_STACK_INPUT, REVERSE_STACK_EXPECTED, 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();
+}
