doc_comments_test.go

package main

import (
	"go/ast"
	"go/parser"
	"go/token"
	"io/fs"
	"path/filepath"
	"strings"
	"testing"
)

func TestNonTestFunctionsHaveDocComments(t *testing.T) {
	err := filepath.WalkDir(".", func(path string, entry fs.DirEntry, walkErr error) error {
		if walkErr != nil {
			return walkErr
		}
		if entry.IsDir() {
			if path != "." && strings.HasPrefix(entry.Name(), ".") {
				return filepath.SkipDir
			}
			return nil
		}
		if !strings.HasSuffix(path, ".go") || strings.HasSuffix(path, "_test.go") {
			return nil
		}

		fileSet := token.NewFileSet()
		file, err := parser.ParseFile(fileSet, path, nil, parser.ParseComments)
		if err != nil {
			return err
		}
		for _, declaration := range file.Decls {
			function, ok := declaration.(*ast.FuncDecl)
			if !ok {
				continue
			}
			if function.Doc == nil || strings.TrimSpace(function.Doc.Text()) == "" {
				t.Errorf("%s: %s lacks a doc comment", fileSet.Position(function.Pos()), function.Name.Name)
			}
		}
		return nil
	})
	if err != nil {
		t.Fatal(err)
	}
}