From df68d9578cc9eecd367214e6c4e467a0e2327238 Mon Sep 17 00:00:00 2001
From: Reilly Grant <reillyg@google.com>
Date: Tue, 28 Mar 2023 16:16:53 -0700
Subject: [PATCH] Fix EnvTest.RunMany to allow parallel execution

As allowed by the documentation for Env::Schedule(), ChromiumEnv may
execute functions on multiple threads and guarantees no sequencing.
EnvTest.RunMany assumed that functions ran in order, is the case for the
stock PosixEnv and WindowsEnv implementations. This change updates the
test to not assume sequential execution.
---
 util/env_test.cc | 27 ++++++++++++++++-----------
 1 file changed, 16 insertions(+), 11 deletions(-)

diff --git a/util/env_test.cc b/util/env_test.cc
index 47174f5..4bdb89b 100644
--- a/util/env_test.cc
+++ b/util/env_test.cc
@@ -96,40 +96,45 @@ TEST_F(EnvTest, RunMany) {
   struct RunState {
     port::Mutex mu;
     port::CondVar cvar{&mu};
-    int last_id = 0;
+    int run_count = 0;
   };
 
   struct Callback {
-    RunState* state_;  // Pointer to shared state.
-    const int id_;  // Order# for the execution of this callback.
+    RunState* const state_;  // Pointer to shared state.
+    bool run = false;
 
-    Callback(RunState* s, int id) : state_(s), id_(id) {}
+    Callback(RunState* s) : state_(s) {}
 
     static void Run(void* arg) {
       Callback* callback = reinterpret_cast<Callback*>(arg);
       RunState* state = callback->state_;
 
       MutexLock l(&state->mu);
-      ASSERT_EQ(state->last_id, callback->id_ - 1);
-      state->last_id = callback->id_;
+      state->run_count++;
+      callback->run = true;
       state->cvar.Signal();
     }
   };
 
   RunState state;
-  Callback callback1(&state, 1);
-  Callback callback2(&state, 2);
-  Callback callback3(&state, 3);
-  Callback callback4(&state, 4);
+  Callback callback1(&state);
+  Callback callback2(&state);
+  Callback callback3(&state);
+  Callback callback4(&state);
   env_->Schedule(&Callback::Run, &callback1);
   env_->Schedule(&Callback::Run, &callback2);
   env_->Schedule(&Callback::Run, &callback3);
   env_->Schedule(&Callback::Run, &callback4);
 
   MutexLock l(&state.mu);
-  while (state.last_id != 4) {
+  while (state.run_count != 4) {
     state.cvar.Wait();
   }
+
+  ASSERT_TRUE(callback1.run);
+  ASSERT_TRUE(callback2.run);
+  ASSERT_TRUE(callback3.run);
+  ASSERT_TRUE(callback4.run);
 }
 
 struct State {