title: How to fill a Django form using test Client
body: <p>I'd like to test my Django forms, but I got this error </p>
  
  <pre><code>django.core.exceptions.ValidationError: ['ManagementForm data is missing or has been tampered with']
  </code></pre>
  
  <p>doing this :</p>
  
  <pre><code> self.client.post(self.url, {"title" : 'title', "status" : 2, "user" :1})
  </code></pre>
  
  <p>And my model only need those fields...</p>
  
  <p>Thank you :)</p>
  
  <p>EDIT 1:
  Here is the form :</p>
  
  <pre><code>class ArticleAdminDisplayable(DisplayableAdmin):
  
      fieldsets = deepcopy(ArticleAdmin.fieldsets)
      list_display = ('title', 'department', 'publish_date', 'status', )
      exclude = ('related_posts',)
      filter_horizontal = ['categories',]
      inlines = [ArticleImageInline,
                 ArticlePersonAutocompleteInlineAdmin,
                 ArticleRelatedTitleAdmin,
                 DynamicContentArticleInline,
                 ArticlePlaylistInline]
      list_filter = [ 'status', 'keywords', 'department', ]
  
  class ArticleAdmin(admin.ModelAdmin):
  
      model = Article
  </code></pre>
  
  <p>About the article model there is too much inheritance so you've to trust me the only fields needed (by the model) are title, status and user. </p>