Table-Driven Tests

Master Go’s idiomatic table-driven testing pattern for comprehensive test coverage.

Background

Table-driven tests are a Go testing best practice where you define test cases as a slice of structs, then loop through them. This pattern makes it easy to add new test cases, see all scenarios at a glance, and get clear output using t.Run() for subtests.

Each test case typically includes: a name, inputs, and expected outputs. The t.Run() function creates a subtest that appears separately in test output and can be run individually.

Your Task

Write table-driven tests for simple calculator functions:

1. Create a test table for Add function with multiple test cases
2. Use t.Run() to execute each test case as a subtest
3. Test the Divide function including error cases (divide by zero)
4. Cover edge cases like negative numbers and zero values

This file has no main(), so the playground compiles it as a test file and runs go test -v. Your subtests have to actually run, call the functions and pass — an empty test table produces no subtest results, and the final TestTablesWereExercised fails if your subtests never call Add and Divide.

Table-Driven Testing Pattern

~15 mineasy

Implement comprehensive table-driven tests for calculator functions

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Key Concepts

• Table-Driven Pattern: Define test cases as a slice of structs for clarity and maintainability
• Subtests with t.Run(): Each test case runs as a named subtest with isolated failure reporting
• Error Testing: Use wantErr boolean field to test both success and error cases
• Edge Cases: Test boundary conditions (zero, negative numbers, error conditions)
• Test Naming: Descriptive names make failures easy to understand and debug