[lldb] Add a SubsystemRAII that takes care of calling Initialize and Terminate in the unit tests

Summary:
Many of our tests need to initialize certain subsystems/plugins of LLDB such as
`FileSystem` or `HostInfo` by calling their static `Initialize` functions before the
test starts and then calling `::Terminate` after the test is done (in reverse order).
This adds a lot of error-prone boilerplate code to our testing code.

This patch adds a RAII called SubsystemRAII that ensures that we always call
::Initialize and then call ::Terminate after the test is done (and that the Terminate
calls are always in the reverse order of the ::Initialize calls). It also gets rid of
all of the boilerplate that we had for these calls.

Per-fixture initialization is still not very nice with this approach as it would
require some kind of static unique_ptr that gets manually assigned/reseted
from the gtest SetUpTestCase/TearDownTestCase functions. Because of that
I changed all per-fixture setup to now do per-test setup which can be done
by just having the SubsystemRAII as a member of the test fixture. This change doesn't
influence our normal test runtime as LIT anyway runs each test case separately
(and the Initialize/Terminate calls are anyway not very expensive). It will however
make running all tests in a single executable slightly slower.

Reviewers: labath, JDevlieghere, martong, espindola, shafik

Reviewed By: labath

Subscribers: mgorny, rnkovacs, emaste, MaskRay, abidh, lldb-commits

Tags: #lldb

Differential Revision: https://reviews.llvm.org/D71630

1 files changed, 2 insertions, 3 deletions

diff --git a/lldb/unittests/Process/minidump/MinidumpParserTest.cpp b/lldb/unittests/Process/minidump/MinidumpParserTest.cpp
index 51c80ecd507..94bb1b395f0 100644
--- a/lldb/unittests/Process/minidump/MinidumpParserTest.cpp
+++ b/lldb/unittests/Process/minidump/MinidumpParserTest.cpp
@@ -10,6 +10,7 @@
 #include "Plugins/Process/minidump/MinidumpTypes.h"
 #include "Plugins/Process/minidump/RegisterContextMinidump_x86_32.h"
 #include "Plugins/Process/minidump/RegisterContextMinidump_x86_64.h"
+#include "TestingSupport/SubsystemRAII.h"
 #include "TestingSupport/TestUtilities.h"
 #include "lldb/Host/FileSystem.h"
 #include "lldb/Target/MemoryRegionInfo.h"
@@ -37,9 +38,7 @@ using namespace minidump;
 
 class MinidumpParserTest : public testing::Test {
 public:
-  void SetUp() override { FileSystem::Initialize(); }
-
-  void TearDown() override { FileSystem::Terminate(); }
+  SubsystemRAII<FileSystem> subsystems;
 
   void SetUpData(const char *minidump_filename) {
     std::string filename = GetInputFilePath(minidump_filename);