1 files changed, 37 insertions, 3 deletions
diff --git a/tests/test_varint.c b/tests/test_varint.c
index 4c076b3..0fc93f0 100644
--- a/tests/test_varint.c
+++ b/tests/test_varint.c
@@ -8,12 +8,39 @@
 #include "upb/pb/varint.h"
 #include "upb_test.h"
 
+// Test that we can round-trip from int->varint->int.
+static void test_varint_for_num(upb_decoderet (*decoder)(const char*),
+                                uint64_t num) {
+  char buf[16];
+  memset(buf, 0xff, sizeof(buf));
+  size_t bytes = upb_vencode64(num, buf);
+
+  if (num <= UINT32_MAX) {
+    char buf2[16];
+    memset(buf2, 0, sizeof(buf2));
+    uint64_t encoded = upb_vencode32(num);
+    memcpy(&buf2, &encoded, 8);
+    upb_decoderet r = decoder(buf2);
+    ASSERT(r.val == num);
+    ASSERT(r.p == buf2 + upb_value_size(encoded));
+    ASSERT(upb_zzenc_32(upb_zzdec_32(num)) == num);
+  }
+
+  upb_decoderet r = decoder(buf);
+  ASSERT(r.val == num);
+  ASSERT(r.p == buf + bytes);
+  ASSERT(upb_zzenc_64(upb_zzdec_64(num)) == num);
+}
+
 static void test_varint_decoder(upb_decoderet (*decoder)(const char*)) {
 #define TEST(bytes, expected_val) {\
-    const char buf[] = bytes "\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff" ; \
+    size_t n = sizeof(bytes) - 1;  /* for NULL */ \
+    char buf[UPB_PB_VARINT_MAX_LEN]; \
+    memset(buf, 0xff, sizeof(buf)); \
+    memcpy(buf, bytes, n); \
     upb_decoderet r = decoder(buf); \
     ASSERT(r.val == expected_val); \
-    ASSERT(r.p == buf + sizeof(buf) - 16);  /* - 1 for NULL */ \
+    ASSERT(r.p == buf + n); \
   }
 
   TEST("\x00",                                                      0ULL);
@@ -30,12 +57,19 @@ static void test_varint_decoder(upb_decoderet (*decoder)(const char*)) {
   TEST("\x81\x83\x87\x8f\x9f\xbf\xff\x81\x83\x07", 0x8303fdf9f1e1c181ULL);
 #undef TEST
 
-  char twelvebyte[16] = {0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x01, 0x01};
+  char twelvebyte[16] = {0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80,
+                         0x80, 0x01, 0x01};
   const char *twelvebyte_buf = twelvebyte;
   // A varint that terminates before hitting the end of the provided buffer,
   // but in too many bytes (11 instead of 10).
   upb_decoderet r = decoder(twelvebyte_buf);
   ASSERT(r.p == NULL);
+
+
+  for (uint64_t num = 5; num * 1.5 > num; num *= 1.5) {
+    test_varint_for_num(decoder, num);
+  }
+  test_varint_for_num(decoder, 0);
 }