Add test for aufile_set_position

Also fix a bug: wav files can contain data after the data chunk. If we don't update nread in aufile_set_position, we can read invalid data.

rem/aufile/aufile.c

@@ -307,8 +307,12 @@ int aufile_set_position(struct aufile *af, const struct aufile_prm *prm,
 	off_t pos = (off_t)(prm->srate * aufmt_sample_size(prm->fmt)
 		* prm->channels * pos_ms / 1000);
 
+	pos = max((off_t)datasize, pos);
+
 	if (fseek(af->f, pos, SEEK_CUR) < 0)
 		return errno;
 
+	af->nread = pos;
+
 	return 0;
 }

test/CMakeLists.txt

@@ -72,6 +72,7 @@ set(SRCS
   aubuf.c
   aulength.c
   aulevel.c
+  aupos.c
   auresamp.c
   av1.c
   base64.c

test/test.c

@@ -55,6 +55,7 @@ static const struct test tests[] = {
 	TEST(test_aubuf),
 	TEST(test_aulength),
 	TEST(test_aulevel),
+	TEST(test_auposition),
 	TEST(test_auresamp),
 	TEST(test_async),
 	TEST(test_av1),

test/test.h

@@ -160,6 +160,7 @@ int test_aes_gcm(void);
 int test_aubuf(void);
 int test_aulevel(void);
 int test_aulength(void);
+int test_auposition(void);
 int test_auresamp(void);
 int test_async(void);
 int test_av1(void);