tests: Add TempDir::IsOk()

Add a small helper for checking whether TempDir was created successfully and
use it instead of checking the temporary directory name directly.

tests/archive/archivetest.cpp

@@ -302,7 +302,7 @@ private:
 ArchiveTempDir::ArchiveTempDir()
     : m_tmp(wxT("arctest-"))
 {
-    CPPUNIT_ASSERT(!m_tmp.GetName().empty());
+    CPPUNIT_ASSERT(m_tmp.IsOk());
     m_original = wxGetCwd();
     CPPUNIT_ASSERT(wxSetWorkingDirectory(m_tmp.GetName()));
 }

tests/filename/filenametest.cpp

@@ -747,7 +747,7 @@ TEST_CASE("wxFileName::Exists", "[filename]")
 #endif // __LINUX__
 #ifndef __VMS
     TempDir socktempdir("socktmpdir");
-    REQUIRE(!socktempdir.GetName().empty());
+    REQUIRE(socktempdir.IsOk());
     wxFileName sockfilename(socktempdir.GetName(), "socket");
     wxString sockfile = sockfilename.GetFullPath();
     wxTCPServer server;
@@ -791,7 +791,7 @@ TEST_CASE("wxFileName::SameAs", "[filename]")
 
 #if defined(__UNIX__)
     TempDir tempdir("wxfn");
-    REQUIRE(!tempdir.GetName().empty());
+    REQUIRE(tempdir.IsOk());
 
     wxFileName tempdir1fn;
     tempdir1fn.AssignDir(tempdir.GetName());
@@ -826,7 +826,7 @@ TEST_CASE("wxFileName::SameAs", "[filename]")
 TEST_CASE("wxFileName::Symlinks", "[filename]")
 {
     TempDir tempdirRoot("filenametest");
-    REQUIRE(!tempdirRoot.GetName().empty());
+    REQUIRE(tempdirRoot.IsOk());
 
     const wxString tmpdir(wxFileName::GetTempDir());
     wxFileName tmpfn(wxFileName::DirName(tmpdir));

tests/fswatcher/fswatchertest.cpp

@@ -133,7 +133,7 @@ public:
             return ms_watchDir;
 
         ms_watchDirData.reset(new TempDir("fswatcher_test"));
-        REQUIRE(!ms_watchDirData->GetName().empty());
+        REQUIRE(ms_watchDirData->IsOk());
 
         TestLogEnabler enableLogs;
         ms_watchDir.AssignDir(ms_watchDirData->GetName());

tests/intl/intltest.cpp

@@ -262,7 +262,7 @@ public:
     TranslationsTestCatalogs()
         : m_prefix("wxintltest-")
     {
-        REQUIRE(!m_prefix.GetName().empty());
+        REQUIRE(m_prefix.IsOk());
 
         CopyCatalog("en_GB");
         CopyCatalog("fr");

tests/testfile.h

@@ -90,6 +90,11 @@ public:
 
     ~TempDir() { Remove(); }
 
+    bool IsOk() const
+    {
+        return !m_name.empty();
+    }
+
     const wxString& GetName() const { return m_name; }
 
     bool Remove()