Changelog

All notable changes to go-testgen will be documented in this file.

The format is based on Keep a Changelog, and this project adheres to Semantic Versioning.

v0.2.1 - 2026-06-16

Added

• --mock-from now accepts full import paths (e.g. io.Writer, net/http.Handler, github.com/x/y.Iface) — the interface is loaded directly without resolving through consuming package imports
• Standalone mock mode — go-testgen gen --mock-from <spec> --pkg <name> --output <file> generates mocks without a consuming package (stdlib and external interfaces)
• --pkg flag — package name for generated mock files (required in standalone mode)
• Single-segment qualifier fallback — --mock-from "io.Writer" retries as direct import path when io isn't imported by the consuming file

Changed

• gen command now accepts zero positional args when --mock-from is present (standalone mode)
• --mock-from help text documents all 4 spec formats

v0.1.5 - [unreleased]

Added

• gen-cases command — reads a .testspec.yaml and materializes test case entries into an existing _test.go
• Inserts struct literal entries into the tests slice with correct field values from the spec
• Generates before/after function stubs with signature inferred from the existing AST
• Emits // ai-hint: comments so a generative AI can complete concrete values
• Idempotent: skips entries that already exist by name; --force replaces them
• --dry-run previews output without writing; --no-hints omits ai-hint comments; --verbose prints a generation summary
• Resolves target _test.go automatically from package + function name (override with --output)
• internal/spec package — YAML types and ParseFile() for .testspec.yaml format
• internal/gencases package — AST-based analysis + text-based insertion pipeline

Added

• AI agent skills — skills/ directory promoted to root with <name>/SKILL.md structure for OpenCode, Claude Code, Cursor, Codex, Gemini compatibility
• scripts/install.sh — curl | bash installer for AI agent skills

Changed

• Moved research/skills/ → skills/ (first-class citizen at repo root)
• skills/AGENTS.md — paths updated to reflect new skill locations
• README.md — AI Agent Skills section updated with curl | bash install command

Removed

• Removed stale root skills/ directory (had corrupt gen-test-cases content)

v0.1.4 - [unreleased]

Added

• Fixed-size array parameter detection — [N]T params now correctly identified in analyzer
• HasArrayResult flag on FuncSummary and ScanResult for array return type detection
• SuggestStyle now recommends check style for functions returning arrays (like slices)

Fixed

• typeToString now preserves array length (e.g. [100]T instead of []T) for both parameters and results
• extractTypePrefix handles [N] prefix, enabling correct identification of array params/results
• qualifiedTypeName correctly drills into array element types for package qualification
• placeholderValue generates [N]T{} zero-value literals for arrays instead of invalid nil
• inspectSignature detects [N] arrays when checking HasSliceResult fallback
• Added unit tests for qualifiedTypeName and placeholderValue with array types

v0.1.3 - 2026-05-08

Added

• Channel type detection and support in analyzer — IsChannel and ChanDir fields on ParamInfo and ResultInfo
• HasChannelParam / HasChannelResult flags on FuncSummary and ScanResult
• Full channel direction support: chan, chan<-, <-chan in typeToString, extractTypePrefix, and resolveTypeExpr
• qualifiedTypeName now handles channel prefixes for correct type qualification
• placeholderValue returns nil for channel types

Changed

• Go toolchain go.mod updated from go 1.26.1 to go 1.26.2

Fixed

• Fixed issue with ignored _ (blank identifier) params
• Fixed missing imports when merging tests
• Fixed error when no .go file is found at project root but go.mod and go.sum are present
• Report command now shows source file location for each function

v0.1.2 - 2026-05-07

Added

• --mock-from accepts bare interface names (e.g. --mock-from mockI2C) and .InterfaceName (e.g. .I2CTransport) for interfaces in the same package
• SourceFile field to scan results (via internal/analyzer)

Changed

• Renamed --test-style flag to --style
• Moved package loading logic to getPackages() helper in internal/analyzer/helpers.go
• ScanPackage now handles module root (.) with no .go files by retrying with ./...
• ScanPackage now merges results from multiple packages (e.g. ./...)
• MergeTestFile now accepts and injects imports into merged test files
• writeOutput / writeToFile now pass import map for smart import injection

Fixed

• Fixed issue with ignored _ (blank identifier) params
• Fixed missing imports when merging tests
• Fixed error when no .go file is found at project root but go.mod and go.sum are present
• Report command now shows source file location for each function

v0.1.1 - 2026-04-23

Fixed

• Factory function instantiation now uses proper placeholder values instead of hardcoded nil
• Report command now shows source file location for each function

Changed

• Fixed repo name in GitLab CI settings
• Renamed site from "go-testgen" to "Go TestGen" in docs

Added

• Gitea CI configuration files
• Homebrew install method documentation in docs
• SourceFile field to scan results for better reporting

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v0.1.0 - 2026-04-16

Added

Core Pipeline: analyze → generate → write

• Three-stage pipeline: AST analysis via go/packages → template-based scaffolding → file write with smart merge
• gen command: generate test scaffolding for a function or method
• FuncSpec accepts plain function name (New, CreateUser) or receiver-qualified method (Service.CreateUser)
• Auto-detects output file (<source>_test.go) when --output is omitted
• --dry-run flag: prints generated code to stdout without writing
• --verbose flag: dumps parsed FuncInfo JSON to stderr before generating
• --mock-from qualifier.InterfaceName: generates a testify mock for the named interface (repeatable flag)
• -o - writes to stdout explicitly
• inspect command: dumps FuncInfo JSON for a function — useful for diagnosing wrong signatures or missing types before running gen
• report command: scans all exported functions and methods in a package and shows test coverage status
• --format text|table|json output modes
• Shows interface dependencies and whether mock files exist
• Prints exact go-testgen gen command to run for each untested function

Test Generation Styles

• check style (default): table-driven tests with closure-based check functions
• Generates a checkXxxFn type alias and checkXxx variadic collector
• Each assertion is an independent named closure composable per test case
• before func(*ReceiverType) field in the table for mock setup and state mutation
• Context parameters (context.Context) are injected automatically, not exposed in the table
• table style: table-driven tests with want value comparison fields
• simple style: standalone test functions without a table

Mock Generation

• --mock-from qualifier.InterfaceName generates a complete testify mock
• Written to mock_<interfacename>_test.go next to the test file
• All interface methods implemented; pointer/slice returns use comma-ok type assertion (r, _ := args.Get(0).(*T)) — safe for nil returns
• Existing mock files are never overwritten

Smart Merge

• If target _test.go exists but does not contain the test function: appends the new test and injects missing imports
• Never overwrites an existing test function

Static Analyzer (internal/analyzer)

• Loads packages via golang.org/x/tools/go/packages
• Extracts FuncInfo: name, package, import path, receiver, params, results, HasError, HasContext
• Resolves interface params — enables mock injection suggestions
• Extracts struct fields from receiver — used for constructor (New) check generation
• Resolves required imports for the generated test file

Generator (internal/generator)

• Template-based code generation using text/template
• Output formatted with go/format.Source; goimports applied when available in PATH
• suggest module: infers go-testgen gen commands for untested functions
• factory module: selects generator implementation based on style

Configuration (internal/config)

• Viper-based config from .go-testgen.yaml
• Search order: explicit --style flag → cwd → $HOME → hardcoded defaults
• Configurable: variable names, testify usage, TODO placeholders, check type suffix, mock/check generation

CLI (cmd/)

• Cobra-based CLI with gen, inspect, report, version subcommands
• version command reports build version

Build & Release

• GoReleaser configuration for multi-platform releases
• GitHub Actions CI/CD workflow
• Platform targets: Linux x86_64/arm64, macOS x86_64/arm64
• Static binaries (CGO_ENABLED=0)

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How to Install

go install github.com/padiazg/go-testgen@latest

Or build from source:

make build
make install