SERVER-35284 Construct unit test fixtures only in the child process in C++ death tests.

(cherry picked from commit 2bc714a6f9a9167e7c447bca6c684f1bce739b17)

2 files changed, 9 insertions, 6 deletions

diff --git a/src/mongo/unittest/death_test.cpp b/src/mongo/unittest/death_test.cpp
index e78a1b6c840..e9def2e6e75 100644
--- a/src/mongo/unittest/death_test.cpp
+++ b/src/mongo/unittest/death_test.cpp
@@ -60,7 +60,8 @@
 namespace mongo {
 namespace unittest {
 
-DeathTestImpl::DeathTestImpl(std::unique_ptr<Test> test) : _test(std::move(test)) {}
+DeathTestImpl::DeathTestImpl(stdx::function<std::unique_ptr<Test>()> makeTest)
+    : _makeTest(std::move(makeTest)) {}
 
 void DeathTestImpl::_doTest() {
 #if defined(_WIN32)
@@ -121,7 +122,8 @@ void DeathTestImpl::_doTest() {
     checkSyscall(setrlimit(RLIMIT_CORE, &kNoCoreDump));
 
     try {
-        _test->run();
+        auto test = _makeTest();
+        test->run();
     } catch (const TestAssertionFailureException& tafe) {
         log() << "Caught test exception while expecting death: " << tafe;
         // To fail the test, we must exit with a successful error code, because the parent process
diff --git a/src/mongo/unittest/death_test.h b/src/mongo/unittest/death_test.h
index 01ab994b70c..ad25f3a3bf7 100644
--- a/src/mongo/unittest/death_test.h
+++ b/src/mongo/unittest/death_test.h
@@ -92,12 +92,12 @@ class DeathTestImpl : public Test {
     MONGO_DISALLOW_COPYING(DeathTestImpl);
 
 protected:
-    DeathTestImpl(std::unique_ptr<Test> test);
+    explicit DeathTestImpl(stdx::function<std::unique_ptr<Test>()> makeTest);
 
 private:
-    void _doTest() override;
+    void _doTest() final;
     virtual std::string getPattern() = 0;
-    std::unique_ptr<Test> _test;
+    const stdx::function<std::unique_ptr<Test>()> _makeTest;
 };
 
 template <typename T>
@@ -106,7 +106,8 @@ public:
     static const std::string pattern;
 
     template <typename... Args>
-    DeathTest(Args&&... args) : DeathTestImpl(stdx::make_unique<T>(std::forward<Args>(args)...)) {}
+    DeathTest(Args&&... args)
+        : DeathTestImpl([args...]() { return stdx::make_unique<T>(args...); }) {}
 
 private:
     std::string getPattern() override {