diff --git a/lldb/unittests/CMakeLists.txt b/lldb/unittests/CMakeLists.txt
--- a/lldb/unittests/CMakeLists.txt
+++ b/lldb/unittests/CMakeLists.txt
@@ -80,6 +80,7 @@
 add_subdirectory(tools)
 add_subdirectory(UnwindAssembly)
 add_subdirectory(Utility)
+add_subdirectory(Thread)
 
 if(LLDB_CAN_USE_DEBUGSERVER AND LLDB_TOOL_DEBUGSERVER_BUILD AND NOT LLDB_USE_SYSTEM_DEBUGSERVER)
   add_subdirectory(debugserver)
diff --git a/lldb/unittests/Thread/CMakeLists.txt b/lldb/unittests/Thread/CMakeLists.txt
new file mode 100644
--- /dev/null
+++ b/lldb/unittests/Thread/CMakeLists.txt
@@ -0,0 +1,15 @@
+add_lldb_unittest(ThreadTest
+  ThreadTest.cpp
+ 
+  LINK_LIBS
+      lldbCore
+      lldbHost
+      lldbTarget
+      lldbSymbol
+      lldbUtility
+      lldbUtilityHelpers
+      lldbInterpreter
+      lldbBreakpoint
+      lldbPluginPlatformLinux
+  )
+
diff --git a/lldb/unittests/Thread/ThreadTest.cpp b/lldb/unittests/Thread/ThreadTest.cpp
new file mode 100644
--- /dev/null
+++ b/lldb/unittests/Thread/ThreadTest.cpp
@@ -0,0 +1,178 @@
+//===-- ThreadTest.cpp ------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "lldb/Target/Thread.h"
+#include "Plugins/Platform/Linux/PlatformLinux.h"
+#include "lldb/Core/Debugger.h"
+#include "lldb/Host/FileSystem.h"
+#include "lldb/Host/HostInfo.h"
+#include "lldb/Target/Process.h"
+#include "lldb/Target/StopInfo.h"
+#include "lldb/Utility/ArchSpec.h"
+#include "lldb/Utility/Reproducer.h"
+#include "gtest/gtest.h"
+
+using namespace lldb_private;
+using namespace lldb_private::repro;
+using namespace lldb;
+
+namespace {
+class ThreadTest : public ::testing::Test {
+public:
+  void SetUp() override {
+    llvm::cantFail(Reproducer::Initialize(ReproducerMode::Off, llvm::None));
+    FileSystem::Initialize();
+    HostInfo::Initialize();
+    platform_linux::PlatformLinux::Initialize();
+  }
+  void TearDown() override {
+    platform_linux::PlatformLinux::Terminate();
+    HostInfo::Terminate();
+    FileSystem::Terminate();
+    Reproducer::Terminate();
+  }
+};
+
+class DummyProcess : public Process {
+public:
+  using Process::Process;
+
+  virtual bool CanDebug(lldb::TargetSP target, bool plugin_specified_by_name) {
+    return true;
+  }
+  virtual Status DoDestroy() { return {}; }
+  virtual void RefreshStateAfterStop() {}
+  virtual size_t DoReadMemory(lldb::addr_t vm_addr, void *buf, size_t size,
+                              Status &error) {
+    return 0;
+  }
+  virtual bool UpdateThreadList(ThreadList &old_thread_list,
+                                ThreadList &new_thread_list) {
+    return false;
+  }
+  virtual ConstString GetPluginName() { return ConstString("Dummy"); }
+  virtual uint32_t GetPluginVersion() { return 0; }
+
+  ProcessModID &GetModIDNonConstRef() { return m_mod_id; }
+};
+
+class DummyThread : public Thread {
+public:
+  using Thread::Thread;
+
+  ~DummyThread() override { DestroyThread(); }
+
+  bool IsStillAtLastBreakpointHit() override { return true; }
+
+  void RefreshStateAfterStop() override {}
+
+  lldb::RegisterContextSP GetRegisterContext() override { return nullptr; }
+
+  lldb::RegisterContextSP
+  CreateRegisterContextForFrame(StackFrame *frame) override {
+    return nullptr;
+  }
+
+  bool CalculateStopInfo() override { return false; }
+};
+} // namespace
+
+TargetSP CreateTarget(DebuggerSP &debugger_sp, ArchSpec &arch) {
+  Status error;
+  PlatformSP platform_sp;
+  TargetSP target_sp;
+  error = debugger_sp->GetTargetList().CreateTarget(
+      *debugger_sp, "", arch, eLoadDependentsNo, platform_sp, target_sp);
+
+  if (target_sp) {
+    debugger_sp->GetTargetList().SetSelectedTarget(target_sp.get());
+  }
+
+  return target_sp;
+}
+
+TEST_F(ThreadTest, SetStopInfo) {
+  ArchSpec arch("powerpc64-pc-linux");
+
+  Platform::SetHostPlatform(
+      platform_linux::PlatformLinux::CreateInstance(true, &arch));
+
+  DebuggerSP debugger_sp = Debugger::CreateInstance();
+  ASSERT_TRUE(debugger_sp);
+
+  TargetSP target_sp = CreateTarget(debugger_sp, arch);
+  ASSERT_TRUE(target_sp);
+
+  ListenerSP listener_sp(Listener::MakeListener("dummy"));
+  ProcessSP process_sp = std::make_shared<DummyProcess>(target_sp, listener_sp);
+  ASSERT_TRUE(process_sp);
+
+  DummyProcess *process = static_cast<DummyProcess *>(process_sp.get());
+
+  ThreadSP thread_sp = std::make_shared<DummyThread>(*process_sp.get(), 0);
+  ASSERT_TRUE(thread_sp);
+
+  StopInfoSP stopinfo_sp =
+      StopInfo::CreateStopReasonWithBreakpointSiteID(*thread_sp.get(), 0);
+  ASSERT_TRUE(stopinfo_sp->IsValid() == true);
+
+  /*
+   Should make stopinfo valid.
+   */
+  process->GetModIDNonConstRef().BumpStopID();
+  ASSERT_TRUE(stopinfo_sp->IsValid() == false);
+
+  thread_sp->SetStopInfo(stopinfo_sp);
+  ASSERT_TRUE(stopinfo_sp->IsValid() == true);
+}
+
+TEST_F(ThreadTest, GetPrivateStopInfo) {
+  ArchSpec arch("powerpc64-pc-linux");
+
+  Platform::SetHostPlatform(
+      platform_linux::PlatformLinux::CreateInstance(true, &arch));
+
+  DebuggerSP debugger_sp = Debugger::CreateInstance();
+  ASSERT_TRUE(debugger_sp);
+
+  TargetSP target_sp = CreateTarget(debugger_sp, arch);
+  ASSERT_TRUE(target_sp);
+
+  ListenerSP listener_sp(Listener::MakeListener("dummy"));
+  ProcessSP process_sp = std::make_shared<DummyProcess>(target_sp, listener_sp);
+  ASSERT_TRUE(process_sp);
+
+  DummyProcess *process = static_cast<DummyProcess *>(process_sp.get());
+
+  ThreadSP thread_sp = std::make_shared<DummyThread>(*process_sp.get(), 0);
+  ASSERT_TRUE(thread_sp);
+
+  StopInfoSP stopinfo_sp =
+      StopInfo::CreateStopReasonWithBreakpointSiteID(*thread_sp.get(), 0);
+  ASSERT_TRUE(stopinfo_sp);
+
+  thread_sp->SetStopInfo(stopinfo_sp);
+
+  /*
+   Should make stopinfo valid if thread is at last breakpoint hit and was
+   not suspended.
+   */
+  process->GetModIDNonConstRef().BumpStopID();
+  ASSERT_TRUE(stopinfo_sp->IsValid() == false);
+  StopInfoSP new_stopinfo_sp = thread_sp->GetPrivateStopInfo();
+  ASSERT_TRUE(new_stopinfo_sp && stopinfo_sp->IsValid() == true);
+
+  /*
+   Should drop stopinfo if thread is still at last breakpoint hit and was
+   suspended.
+   */
+  thread_sp->SetResumeState(eStateSuspended);
+  process->GetModIDNonConstRef().BumpStopID();
+  new_stopinfo_sp = thread_sp->GetPrivateStopInfo();
+  ASSERT_TRUE(new_stopinfo_sp == nullptr);
+}