Day 8 — Gate I: Core Language Checkpoint

Day 8 — Gate I: Core Language Checkpoint

Today is your first gate. Review everything from Days 1–7 and verify you can work confidently with Go’s core language features.

Self-assessment checklist

• Set up a Go module from scratch (go mod init)
• Declare variables with both var and :=, understand zero values
• Write functions with multiple returns, named returns, and variadic parameters
• Use if, switch, for (including range) confidently
• Create and manipulate slices (append, copy, reslicing)
• Use maps with comma-ok pattern
• Define structs with methods (value and pointer receivers)
• Understand pointer semantics and escape analysis basics
• Organize code into packages with proper visibility
• Define and implement interfaces (implicit satisfaction)
• Use type assertions and type switches
• Handle errors idiomatically (error interface, wrapping with %w, errors.Is/As)
• Use panic/recover appropriately (rare cases only)
• Understand Go modules (go.mod, go.sum, go get, go mod tidy)
• Write table-driven tests with t.Run() subtests
• Create test fakes/mocks using interfaces

Gate project

Build a CLI tool that:

1. Accepts command-line arguments
2. Uses at least 3 custom types with methods
3. Implements at least 1 interface
4. Has proper error handling (no panics for expected errors)
5. Includes table-driven tests with >80% coverage
6. Is organized into multiple packages

Run go vet and go test -race ./... — both must pass cleanly.

Tip

If any checklist item feels uncertain, revisit that day’s material before proceeding to Stage II.