Populate LevelConceptDifficulty fixture to fix assert_nil warning

[joshlory]

Before adding this fixture, "level_concept_difficulty uses preloading" in ScriptTest only compared nil to nil.

Fixes:

Use assert_nil if expecting nil from /home/ubuntu/code-dot-org/dashboard/test/models/script_test.rb:346:in `block in <class:ScriptTest>'. This will fail in MT6.
  test_level_concept_difficulty_uses_preloading                   PASS (0.08s)

[ashercodeorg]

AFAICT (though I'm not 100% certain), this change shouldn't be necessary. Presumably, if the DB is disconnected, the call to level_concept_difficulty should blow up unless preloading occurred (regardless of whether the level_concept_difficulty is nil or non-nil? If so, I would suggest simplifying the test to use assert_nil (removing expected).

[Hamms]

Oh dang, that's an unfortunate oversight.

What we probably actually want to do is add an assert_not_nil somewhere before line 344

[joshlory]

@ashercodeorg I'm not sure I follow. This is the code for the test:

test 'level_concept_difficulty uses preloading' do
  level = Script.find_by_name('course4').script_levels.second.level
  expected = level.level_concept_difficulty

  populate_cache_and_disconnect_db

  assert_equal expected, level.level_concept_difficulty
end

Without this change, Script.find_by_name('course4').script_levels.second.level has no level_concept_difficulty.

[ashercodeorg]

Right. But you need the DB to know that it has no level_concept_difficulty. It isn't clear to me that the test isn't successfully testing what it wants to test, regardless of whether the level_concept_difficulty exists.

[joshlory]

Ah, I see what you're saying. Added an assert_not_nil in cbd9b38. PTAL!

[ashercodeorg]

LGTM.