Merge bitcoin#529: fix tests.c in the count == 0 case

95e99f1 fix tests.c in the count == 0 case (Andrew Poelstra)

Pull request description:

  Fixes bitcoin#528

Tree-SHA512: 8b28d84f95bcd1337fbd7fb187dee2a9bad2b6b595eaf42a2d855e5784f48a1f3ad5739881b22eea115d32c4525feb69b41958699a165c847fcfb8096cc4903a

Author: sipa

src/tests.c

@@ -2725,6 +2725,11 @@ void test_ecmult_multi(secp256k1_scratch *scratch, secp256k1_ecmult_multi_func e
     }
 
     /* Sanity check that zero scalars don't cause problems */
+    for (ncount = 0; ncount < 20; ncount++) {
+        random_scalar_order(&sc[ncount]);
+        random_group_element_test(&pt[ncount]);
+    }
+
     secp256k1_scalar_clear(&sc[0]);
     CHECK(ecmult_multi(&ctx->ecmult_ctx, scratch, &r, &szero, ecmult_multi_callback, &data, 20));
     secp256k1_scalar_clear(&sc[1]);