Fix HPACK encoder test

src/core/transport/metadata.c

@@ -132,6 +132,7 @@ typedef struct mdtab_shard {
 
 /* hash seed: decided at initialization time */
 static gpr_uint32 g_hash_seed;
+static int g_forced_hash_seed = 0;
 
 /* linearly probed hash tables for static element lookup */
 static grpc_mdstr *g_static_strtab[GRPC_STATIC_MDSTR_COUNT * 2];
@@ -144,9 +145,16 @@ static mdtab_shard g_mdtab_shard[MDTAB_SHARD_COUNT];
 
 static void gc_mdtab(mdtab_shard *shard);
 
+void grpc_test_only_set_metadata_hash_seed(gpr_uint32 seed) {
+  g_hash_seed = seed;
+  g_forced_hash_seed = 1;
+}
+
 void grpc_mdctx_global_init(void) {
   size_t i, j;
-  g_hash_seed = (gpr_uint32)gpr_now(GPR_CLOCK_REALTIME).tv_nsec;
+  if (!g_forced_hash_seed) {
+    g_hash_seed = (gpr_uint32)gpr_now(GPR_CLOCK_REALTIME).tv_nsec;
+  }
   g_static_strtab_maxprobe = 0;
   g_static_mdtab_maxprobe = 0;
   /* build static tables */

src/core/transport/metadata.h

@@ -86,11 +86,7 @@ struct grpc_mdelem {
   /* there is a private part to this in metadata.c */
 };
 
-/* Test only accessors to internal state - only for testing this code - do not
-   rely on it outside of metadata_test.c */
-size_t grpc_mdctx_get_mdtab_capacity_test_only(void);
-size_t grpc_mdctx_get_mdtab_count_test_only(void);
-size_t grpc_mdctx_get_mdtab_free_test_only(void);
+void grpc_test_only_set_metadata_hash_seed(gpr_uint32 seed);
 
 /* Constructors for grpc_mdstr instances; take a variety of data types that
    clients may have handy */

test/core/transport/chttp2/hpack_encoder_test.c

@@ -37,6 +37,7 @@
 
 #include "src/core/support/string.h"
 #include "src/core/transport/chttp2/hpack_parser.h"
+#include "src/core/transport/metadata.h"
 #include <grpc/support/alloc.h>
 #include <grpc/support/log.h>
 #include <grpc/support/string_util.h>
@@ -187,6 +188,7 @@ static void run_test(void (*test)(), const char *name) {
 
 int main(int argc, char **argv) {
   size_t i;
+  grpc_test_only_set_metadata_hash_seed(0);
   grpc_test_init(argc, argv);
   grpc_init();
   TEST(test_basic_headers);