Minitest basics (assert style) in Ruby - Step-by-Step Execution

Concept Flow - Minitest basics (assert style)

Write test method

↓

Call assert method

↓

Evaluate condition

↓

Pass

↓

Report result

↓

Next test or end

Tests run by calling assert methods that check conditions; if true, test passes, else it fails and reports.

Execution Sample

Ruby

require 'minitest/autorun'

class TestExample < Minitest::Test
  def test_sum
    assert_equal 4, 2 + 2
  end
end

This code defines a test that checks if 2 + 2 equals 4 using assert_equal.

Execution Table

Step	Action	Evaluation	Result
1	Run test_sum method	assert_equal 4, 2 + 2	Check if 4 == 4
2	Evaluate condition	4 == 4	True
3	Test result	Pass	No error raised
4	Report	Test passed	Output success message
5	End	All tests done	Exit

💡 Test ends after all assertions pass or fail; here assertion is true so test passes.

Variable Tracker

Variable	Start	After Step 1	After Step 2	Final
expected	4	4	4	4
actual	undefined	2 + 2	4	4
assertion_result	undefined	undefined	true	true

Key Moments - 3 Insights

Why does the test pass even though we don't see any output?

Because assert_equal passes silently when the condition is true, as shown in execution_table step 3 and 4.

What happens if the assertion fails?

If the assertion fails, Minitest raises an error and reports failure immediately, unlike the pass case in execution_table.

Why do we use assert_equal instead of just comparing values?

assert_equal provides clear pass/fail reporting and integrates with Minitest framework, as shown in the flow from calling assert to reporting.

Visual Quiz - 3 Questions

Look at the execution_table, what is the evaluation result at Step 2?

A Error

B False

C True

D Undefined

💡 Hint

Check the 'Evaluation' and 'Result' columns at Step 2 in execution_table.

At which step does the test report success?

A Step 4

B Step 3

C Step 1

D Step 5

💡 Hint

Look for the step where 'Test passed' is mentioned in execution_table.

If the assertion was false, what would change in the execution_table?

A Step 1 would be skipped

B Step 2 evaluation would be False and Step 3 would show failure

C Step 5 would report success

D No changes, test always passes

💡 Hint

Refer to key_moments about assertion failure and execution_table step 2 and 3.

Concept Snapshot

Minitest uses assert methods to check conditions.
assert_equal(expected, actual) tests equality.
If true, test passes silently.
If false, test fails with error.
Tests are methods inside classes inheriting from Minitest::Test.
Run tests with 'ruby filename.rb'.

Full Transcript

This visual trace shows how a Minitest assert style test runs. First, the test method is called. Then the assert_equal method compares expected and actual values. If they match, the assertion passes silently and the test reports success. If they don't match, Minitest raises an error and reports failure. Variables like expected and actual hold values during the test. The key moments explain why tests pass silently and what happens on failure. The quiz checks understanding of evaluation results and reporting steps. This helps beginners see how Minitest checks conditions step-by-step.