Fundamentals of Testing Using Rails/

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Minitest Basics

Minitest Basics

Learn Minitest syntax, methods, and assertion methods and learn to write the first test on Minitest.

We'll cover the following...

Minitest syntax

Our project’s test directory contains Minitest equivalents of many of the RSpec tests we’ve written thus far.

Here’s an example, specifically, the tests for the Task model:

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require "test_helper"
class TaskTest < ActiveSupport::TestCase
    test "a completed task is complete" do
        task = Task.new
        refute(task.complete?)
        task.mark_completed
        assert(task.complete?)
    end
    test "an uncompleted task does not count toward velocity" do
        task = Task.new(size: 3)
        refute(task.part_of_velocity?)
        assert_equal(0, task.points_toward_velocity)
    end
    test "a task completed long ago does not count toward velocity" do
        task = Task.new(size: 3)
        task.mark_completed(6.months.ago)
        refute(task.part_of_velocity?)
        assert_equal(0, task.points_toward_velocity)
    end
    test "a task completed recently counts toward velocity" do
        task = Task.new(size: 3)
        task.mark_completed(1.day.ago)
        assert(task.part_of_velocity?)
        assert_equal(3, task.points_toward_velocity)
    end
end

This looks broadly similar to the RSpec we’ve been looking at, but the syntax has some clear differences. Let’s take a look at the main ones.

On line 1 the file test_helper is required. It contains Rails and application-related setup common to all Minitest files. It’s the file to which we just added Mocha.

Minitest methods

In Minitest, we can’t put a test method just anywhere or name it just anything; tests need to be methods of a subclass of the class Minitest::Test. (The class ActiveSupport::TestCase that the test uses is, in fact, a subclass of Minitest::Test). In standard Minitest, a test method is any method whose name starts with test_, as in ...