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POHow to lazily evaluate ORM call after fixtures are loaded into db in Django?
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  1. POHow to lazily evaluate ORM call after fixtures are loaded into db in Django?
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    copied!<p>I've got a module <code>pagetypes.py</code> that extracts a couple of constants (I shouldn't really use word constant here) from the db for later reuse:</p> <pre><code>def _get_page_type_(type): return PageType.objects.get(type=type) PAGE_TYPE_MAIN = _get_page_type_('Main') PAGE_TYPE_OTHER = _get_page_type_('Other') </code></pre> <p>then somewhere in views I do:</p> <pre><code>import pagetypes ... print pagetypes.PAGE_TYPE_MAIN #simplified </code></pre> <p>It all works fine when db has those records and I make sure it does... unless this code is under test. In that case I want to load those records into db via fixtures. The problem with that is that fixtures are not loaded (even <code>syncdb</code> is not run) by the time pagetypes module is imported resulting in <code>_get_page_type_</code> call failing with:</p> <pre><code>psycopg2.ProgrammingError: relation "pagetype" does not exist </code></pre> <p>Test runner always tries to import <code>pagetypes</code> module, because it is imported by view that is under test. </p> <p>How do I get around this problem?</p> <p>I was thinking of lazily loading pagetype constants <code>PAGE_TYPE_MAIN</code>, <code>PAGE_TYPE_OTHER</code>, but then I want it to fail early if those records are not in the db (or fixtures if under test), so I don't really know how to implement this.</p> <p>I was also thinking of object level caching and just call <code>PageType.objects.get(type=type)</code> whenever constant is used/called, but wouldn't that be an overkill? Calling orm without cache would result in too many db calls, which I want to prevent.</p> <p>It must be something very simple, but I can't work it out. ;-)</p>
 

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