add an EXPECT_NE() to check for nullptr before derefencing it. Avoids segfault. But the test is still red.

test/unittest_message.cc

@@ -118,6 +118,8 @@ TEST( MessageTest, Simple )
     pEp::Message msg{PEP_dir_outgoing, mail1_eml};
     
     EXPECT_EQ(msg->dir, PEP_dir_outgoing);
+    ASSERT_NE(msg->from, nullptr);
+    
     EXPECT_STREQ( msg->from->username, "Alice");
     EXPECT_STREQ( msg->shortmsg, "Rødgrød med fløde" );
     EXPECT_STREQ( msg->longmsg , "Rødgrød med fløde?\r\n" );