Add test fixtures

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Test fixtures provide test data to be used by our automated tests.

• When a model class is generated with the rails generate model command (or via Devise), test fixtures for the model class are also generated.
  • Test fixtures folder: test/fixtures
• Thus, each of the LimerIQ app’s two model classes has a corresponding fixture file:
  • Limerick → limericks.yml
  • User → users.yml
• Note that the fixture files have names that are snake_case and pluralized versions of the model class names.
  • Example: Model class MultipleChoiceQuestion would have a fixture file multiple_choice_questions.yml.
• Note that the fixtures are written using the YAML language.

Tasks

• Inspect the test fixtures generated by default.
• Add realistic data to the fixtures.

Inspect the test fixtures generated by default

• Open the limericks.yml fixtures file in VS Code. You should see entries like this:

one:
  title: MyString
  limerick_text: MyText

two:
  title: MyString
  limerick_text: MyText

• Note that there are two Limerick objects specified here.
  • One is named one and the other is named two.
  • We will use these names to retrieve fixture objects later when we write our controller tests.
• Note that each object has its title and limerick_text attributes set to the generated placeholder values MyString and MyText, respectively.
  • We will replace these placeholders with more realistic values in a moment.
• Open the users.yml fixtures file in VS Code. You should see entries like this (comments elided):

one: {}

two: {}

• Note that these two User objects have no attribute values specified, as indicated by the empty braces {}.
  • We will add attribute values to these fixtures in a moment.

• Note that it is a common practice to name each fixture of a given type one, two, etc.; however, following this naming convention is not strictly required.

• Note that it is also common to have two fixtures of each type; however, more fixtures can be added if needed by our tests.

Add realistic data to the fixtures

• Update the User fixtures by adding an email attribute with a realistic value to each user.

one:
  email: alice@email.com

two:
  email: bob@email.com

• Note that we deleted the empty braces {}, which denote that a fixture has no attributes.

• Note that for User fixtures, it is unnecessary to add any other attributes (such as password).

• Update the Limerick fixtures’ title and limerick_text attribute values to be more realistic by editing them in VS Code as in the code below.

• Additionally, recall that there is a has_many/belongs_to association between the User and Limerick classes. Because the belongs_to declaration includes an implicit validation that an associated object is present, we must add to each of our Limerick fixtures an association link to a User fixture. To accomplish this, we must add an additional association-link attribute to each Limerick fixture. To determine the name of the association-link attribute to add, inspect the belongs_to declaration in the Limerick class, and note that :author is the name specified for the associated User object. Thus, we add an author attribute to each of our Limerick fixtures as follows.

one:
  title: There once was a farmer from Leeds
  limerick_text: "There once was a farmer from Leeds,\nWho swallowed a packet of seeds.\nIt soon came to pass,\nHe was covered with grass,\nBut has all the tomatoes he needs."
  author: one

two:
  title: A canner, exceedingly canny
  limerick_text: "A canner, exceedingly canny\nOne morning remarked to his granny,\n\"A canner can can\nAnything that he can;\nBut a canner can't can a can, can he?\""
  author: one

• Note that because the limerick_text string values contain special escape sequences (\n to print a newline and \" to print a quotation mark), those strings must be surrounded in quotation marks (").
  • In contrast, the title string values do not contain escape sequences and therefore need not be surrounded in quotation marks.
• Note that each fixture now has an author attribute, and each such attribute is set to one.
  • The name one in this case refers to the User fixture named one from the users.yml fixture file.
  • That means that each of the Limerick feature objects belongs to the same User fixture object (one).
  • The User fixture object two has no Limerick objects in these fixtures.

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