diff --git a/clang-tools-extra/clangd/unittests/CodeCompleteTests.cpp b/clang-tools-extra/clangd/unittests/CodeCompleteTests.cpp
--- a/clang-tools-extra/clangd/unittests/CodeCompleteTests.cpp
+++ b/clang-tools-extra/clangd/unittests/CodeCompleteTests.cpp
@@ -27,6 +27,8 @@
 #include "llvm/Testing/Support/Error.h"
 #include "gmock/gmock.h"
 #include "gtest/gtest.h"
+#include <condition_variable>
+#include <mutex>
 
 namespace clang {
 namespace clangd {
@@ -1112,8 +1114,10 @@
   bool
   fuzzyFind(const FuzzyFindRequest &Req,
             llvm::function_ref<void(const Symbol &)> Callback) const override {
-    std::lock_guard<std::mutex> Lock(Mut);
+    std::unique_lock<std::mutex> Lock(Mut);
     Requests.push_back(Req);
+    ReceivedRequest = true;
+    ReceivedRequestCV.notify_one();
     return true;
   }
 
@@ -1132,7 +1136,9 @@
   size_t estimateMemoryUsage() const override { return 0; }
 
   const std::vector<FuzzyFindRequest> consumeRequests() const {
-    std::lock_guard<std::mutex> Lock(Mut);
+    std::unique_lock<std::mutex> Lock(Mut);
+    ReceivedRequestCV.wait(Lock, [this]() { return ReceivedRequest; });
+    ReceivedRequest = false;
     auto Reqs = std::move(Requests);
     Requests = {};
     return Reqs;
@@ -1140,7 +1146,9 @@
 
 private:
   // We need a mutex to handle async fuzzy find requests.
+  mutable std::condition_variable ReceivedRequestCV;
   mutable std::mutex Mut;
+  mutable bool ReceivedRequest = false;
   mutable std::vector<FuzzyFindRequest> Requests;
 };
 
@@ -2098,9 +2106,6 @@
 
   auto CompleteAtPoint = [&](StringRef P) {
     cantFail(runCodeComplete(Server, File, Test.point(P), Opts));
-    // Sleep for a while to make sure asynchronous call (if applicable) is also
-    // triggered before callback is invoked.
-    std::this_thread::sleep_for(std::chrono::milliseconds(100));
   };
 
   CompleteAtPoint("1");