[fuzzing] Add TickUntil variants to FuzzingEventEngine (#34308)

Sometimes we just want to wait until a specific time

test/core/event_engine/fuzzing_event_engine/fuzzing_event_engine.cc

@@ -180,6 +180,28 @@ void FuzzingEventEngine::TickUntilIdle() {
   }
 }
 
+void FuzzingEventEngine::TickUntil(Time t) {
+  while (true) {
+    auto now = Now();
+    if (now >= t) break;
+    Tick(t - now);
+  }
+}
+
+void FuzzingEventEngine::TickUntilTimespec(gpr_timespec t) {
+  GPR_ASSERT(t.clock_type != GPR_TIMESPAN);
+  TickUntil(Time() + std::chrono::seconds(t.tv_sec) +
+            std::chrono::nanoseconds(t.tv_nsec));
+}
+
+void FuzzingEventEngine::TickUntilTimestamp(grpc_core::Timestamp t) {
+  TickUntilTimespec(t.as_timespec(GPR_CLOCK_REALTIME));
+}
+
+void FuzzingEventEngine::TickForDuration(grpc_core::Duration d) {
+  TickUntilTimestamp(grpc_core::Timestamp::Now() + d);
+}
+
 FuzzingEventEngine::Time FuzzingEventEngine::Now() {
   grpc_core::MutexLock lock(&*now_mu_);
   return now_;

test/core/event_engine/fuzzing_event_engine/fuzzing_event_engine.h

@@ -41,6 +41,7 @@
 
 #include "src/core/lib/gprpp/no_destruct.h"
 #include "src/core/lib/gprpp/sync.h"
+#include "src/core/lib/gprpp/time.h"
 #include "test/core/event_engine/fuzzing_event_engine/fuzzing_event_engine.pb.h"
 #include "test/core/util/port.h"
 
@@ -59,6 +60,8 @@ class FuzzingEventEngine : public EventEngine {
                               const fuzzing_event_engine::Actions& actions);
   ~FuzzingEventEngine() override { UnsetGlobalHooks(); }
 
+  using Time = std::chrono::time_point<FuzzingEventEngine, Duration>;
+
   // Once the fuzzing work is completed, this method should be called to speed
   // quiescence.
   void FuzzingDone() ABSL_LOCKS_EXCLUDED(mu_);
@@ -67,6 +70,14 @@ class FuzzingEventEngine : public EventEngine {
       ABSL_LOCKS_EXCLUDED(mu_);
   // Repeatedly call Tick() until there is no more work to do.
   void TickUntilIdle() ABSL_LOCKS_EXCLUDED(mu_);
+  // Tick until some time
+  void TickUntil(Time t) ABSL_LOCKS_EXCLUDED(mu_);
+  // Tick until some gpr_timespec
+  void TickUntilTimespec(gpr_timespec t) ABSL_LOCKS_EXCLUDED(mu_);
+  // Tick until some grpc_core::Timestamp
+  void TickUntilTimestamp(grpc_core::Timestamp t) ABSL_LOCKS_EXCLUDED(mu_);
+  // Tick for some grpc_core::Duration
+  void TickForDuration(grpc_core::Duration d) ABSL_LOCKS_EXCLUDED(mu_);
 
   absl::StatusOr<std::unique_ptr<Listener>> CreateListener(
       Listener::AcceptCallback on_accept,
@@ -97,8 +108,6 @@ class FuzzingEventEngine : public EventEngine {
       ABSL_LOCKS_EXCLUDED(mu_) override;
   bool Cancel(TaskHandle handle) ABSL_LOCKS_EXCLUDED(mu_) override;
 
-  using Time = std::chrono::time_point<FuzzingEventEngine, Duration>;
-
   Time Now() ABSL_LOCKS_EXCLUDED(mu_);
 
   // Clear any global hooks installed by this event engine. Call prior to