We have some tests implemented which use QTemporaryFile. We've found that some tests fail when upgrading from Qt 5.9.8 to Qt 5.11.3, if QTemporaryFile#fileName() doesn't get called after calling QTemporaryFile#open(). We use Xubuntu 16.04 for development.

Basically, this is the simplest test case:

TEST(tempFileTest, test1) 
{ 
  QTemporaryFile temp; 
  ASSERT_TRUE(temp.open()); 
  ASSERT_TRUE(temp.exists()); //Fails here 
} 

TEST(tempFileTest, test2) 
{ 
  QTemporaryFile temp; 
  ASSERT_TRUE(temp.open()); 
  temp.fileName(); 
  ASSERT_TRUE(temp.exists()); //Passes 
}