logos-storage-docs-obsidian/10 Notes/go testify assertions.md

Some summary about testify assertions.

assert.Equal() Function Signature

func Equal(t TestingT, expected, actual interface{}, msgAndArgs ...interface{}) bool

Parameters Breakdown:

1. t TestingT - The testing interface (first parameter)
2. expected interface{} - What you expect the value to be
3. actual interface{} - The actual value you're testing
4. msgAndArgs ...interface{} - Optional custom message and formatting arguments

What is suite.T()?

When you're using testify's test suite pattern, suite.T() returns the underlying *testing.T instance associated with the current test method.

type CodexArchiveDownloaderTestifySuite struct {
    suite.Suite  // Embeds testify's Suite type
    // ... other fields
}

func (suite *CodexArchiveDownloaderTestifySuite) TestBasicSingleArchive() {
    // suite.T() returns the *testing.T for this specific test method
    assert.Equal(suite.T(), 1, downloader.GetTotalArchivesCount())
}

Comparison: Suite vs Function-Based

In Test Suite (what you're seeing):

assert.Equal(suite.T(), expected, actual, "optional message")

In Regular Function-Based Test:

func TestSomething(t *testing.T) {
    assert.Equal(t, expected, actual, "optional message")
}

Why suite.T() is Needed

The testify suite embeds a *testing.T, but assertions need direct access to it for:

• Reporting failures
• Marking tests as failed
• Logging output
• Integration with Go's test runner

Other Common Assert Functions

// Basic equality
assert.Equal(t, expected, actual)
assert.NotEqual(t, expected, actual)

// Boolean checks  
assert.True(t, condition)
assert.False(t, condition)

// Nil checks
assert.Nil(t, value)
assert.NotNil(t, value)

// Collection checks
assert.Len(t, collection, expectedLength)
assert.Contains(t, collection, element)
assert.Empty(t, collection)

// Error checks
assert.NoError(t, err)
assert.Error(t, err)

// Type checks
assert.IsType(t, expectedType, actual)

// All with optional custom messages
assert.Equal(t, 42, result, "The calculation should return 42")
assert.True(t, isValid, "Validation should pass for input: %s", input)

require vs assert

Both take the same parameters, but behave differently on failure:

// assert continues test execution on failure
assert.Equal(t, 1, count)
assert.True(t, isReady)  // This will still run even if above fails

// require stops test execution immediately on failure
require.Equal(t, 1, count)
require.True(t, isReady)  // This won't run if above fails

In Your Code Context

// Line 90 you're looking at:
assert.Equal(suite.T(), 1, downloader.GetTotalArchivesCount(), "Total archives count should be 1")

This means:

• suite.T() - The testing context from the suite
• 1 - Expected value
• downloader.GetTotalArchivesCount() - Actual value being tested
• "Total archives count should be 1" - Custom error message if assertion fails

The assertion will fail if GetTotalArchivesCount() returns anything other than 1, and it will display your custom message along with the expected vs actual values.