test: add tests (#3)

codegen.go

@@ -0,0 +1,90 @@
+package main
+
+import (
+	"fmt"
+	"io"
+	"sort"
+	"strings"
+	"text/template"
+
+	"gopkg.in/yaml.v3"
+)
+
+var tmpl = template.Must(template.New("").Funcs(funcs).Parse(
+	`// Code generated by go-simpler.org/slog-gen. DO NOT EDIT.
+
+package {{.Pkg}}
+
+{{range .Imports -}}
+import "{{.}}"
+{{end -}}
+
+{{range $_, $attr := .Attrs}}
+func {{snakeToCamel $attr.Key}}(value {{$attr.Type}}) slog.Attr {
+	return slog.{{slogFunc $attr.Type}}("{{$attr.Key}}", value)
+}
+{{end}}`,
+))
+
+type (
+	config struct {
+		Pkg     string
+		Imports []string
+		Attrs   []attr
+	}
+	attr struct {
+		Key  string
+		Type string
+	}
+)
+
+func readConfig(r io.Reader) (config, error) {
+	var cfg struct {
+		Pkg     string            `yaml:"pkg"`
+		Imports []string          `yaml:"imports"`
+		Attrs   map[string]string `yaml:"attrs"` // key:type
+	}
+	if err := yaml.NewDecoder(r).Decode(&cfg); err != nil {
+		return config{}, fmt.Errorf("decoding config: %w", err)
+	}
+
+	cfg.Imports = append(cfg.Imports, "log/slog")
+	sort.Strings(cfg.Imports)
+
+	// TODO: rewrite when maps.Keys() is released.
+	keys := make([]string, 0, len(cfg.Attrs))
+	for key := range cfg.Attrs {
+		keys = append(keys, key)
+	}
+	sort.Strings(keys)
+
+	attrs := make([]attr, len(keys))
+	for i, key := range keys {
+		attrs[i] = attr{Key: key, Type: cfg.Attrs[key]}
+	}
+
+	return config{
+		Pkg:     cfg.Pkg,
+		Imports: cfg.Imports,
+		Attrs:   attrs,
+	}, nil
+}
+
+// nolint:staticcheck // SA1019: strings.Title is deprecated but works just fine here.
+var funcs = template.FuncMap{
+	"snakeToCamel": func(s string) string {
+		parts := strings.Split(s, "_")
+		for i := range parts {
+			parts[i] = strings.Title(parts[i])
+		}
+		return strings.Join(parts, "")
+	},
+	"slogFunc": func(typ string) string {
+		switch s := strings.Title(strings.TrimPrefix(typ, "time.")); s {
+		case "String", "Int64", "Int", "Uint64", "Float64", "Bool", "Time", "Duration":
+			return s
+		default:
+			return "Any"
+		}
+	},
+}

codegen_test.go

@@ -0,0 +1,65 @@
+package main
+
+import (
+	"bytes"
+	"strings"
+	"testing"
+
+	"go-simpler.org/assert"
+	. "go-simpler.org/assert/dotimport"
+)
+
+func Test_tmplExecute(t *testing.T) {
+	cfg := config{
+		Pkg:     "test",
+		Imports: []string{"log/slog"},
+		Attrs: []attr{
+			{Key: "foo", Type: "int"},
+			{Key: "bar", Type: "error"},
+		},
+	}
+
+	const codegen = `// Code generated by go-simpler.org/slog-gen. DO NOT EDIT.
+
+package test
+
+import "log/slog"
+
+func Foo(value int) slog.Attr {
+	return slog.Int("foo", value)
+}
+
+func Bar(value error) slog.Attr {
+	return slog.Any("bar", value)
+}
+`
+
+	var buf bytes.Buffer
+	err := tmpl.Execute(&buf, cfg)
+	assert.NoErr[F](t, err)
+	assert.Equal[E](t, buf.String(), codegen)
+}
+
+func Test_readConfig(t *testing.T) {
+	r := strings.NewReader(`
+pkg: test
+imports:
+  - time
+attrs:
+  foo: time.Time
+  bar: time.Duration
+`)
+
+	want := config{
+		Pkg:     "test",
+		Imports: []string{"log/slog", "time"},
+		Attrs: []attr{
+			{Key: "bar", Type: "time.Duration"},
+			{Key: "foo", Type: "time.Time"},
+		},
+	}
+
+	got, err := readConfig(r)
+	assert.NoErr[F](t, err)
+	assert.Equal[E](t, got, want)
+}

go.mod

@@ -3,6 +3,7 @@ module go-simpler.org/slog-gen
 go 1.21.0
 
 require (
+	go-simpler.org/assert v0.6.0
 	go-simpler.org/errorsx v0.7.0
 	gopkg.in/yaml.v3 v3.0.1
 )

go.sum

@@ -1,3 +1,5 @@
+go-simpler.org/assert v0.6.0 h1:QxSrXa4oRuo/1eHMXSBFHKvJIpWABayzKldqZyugG7E=
+go-simpler.org/assert v0.6.0/go.mod h1:74Eqh5eI6vCK6Y5l3PI8ZYFXG4Sa+tkr70OIPJAUr28=
 go-simpler.org/errorsx v0.7.0 h1:KtOhEDzn8WzjEwv0qt/TB44gARqBMm3mRehU2H8YMso=
 go-simpler.org/errorsx v0.7.0/go.mod h1:j33G4x0zmHYKTtxq6sX3NJtaOljcDcc2XdK8kp23yTw=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=

main.go

@@ -5,14 +5,13 @@ import (
 	"flag"
 	"fmt"
 	"os"
-	"sort"
-	"strings"
-	"text/template"
+	"path/filepath"
 
 	"go-simpler.org/errorsx"
-	"gopkg.in/yaml.v3"
 )
 
+//go:generate go run main.go codegen.go -config=.slog.yml
+
 func main() {
 	if err := run(); err != nil {
 		fmt.Println(err)
@@ -24,113 +23,35 @@ func run() (err error) {
 	var cfgPath string
 
 	fs := flag.NewFlagSet("slog-gen", flag.ContinueOnError)
-	fs.StringVar(&cfgPath, "config", ".slog.yml", "config path")
+	fs.StringVar(&cfgPath, "config", ".slog.yml", "path to config")
 	if err := fs.Parse(os.Args[1:]); err != nil {
 		return fmt.Errorf("parsing flags: %w", err)
 	}
 
-	cfg, err := loadConfig(cfgPath)
+	cfgFile, err := os.Open(cfgPath)
+	if err != nil {
+		return fmt.Errorf("opening file: %w", err)
+	}
+	defer errorsx.Close(cfgFile, &err)
+
+	cfg, err := readConfig(cfgFile)
 	if err != nil {
 		return err
 	}
 
 	if err := os.Mkdir(cfg.Pkg, 0o755); err != nil && !errors.Is(err, os.ErrExist) {
-		return fmt.Errorf("mkdir %s: %w", cfg.Pkg, err)
+		return fmt.Errorf("mkdir: %w", err)
 	}
 
-	f, err := os.Create(cfg.Pkg + "/attr.go")
+	genFile, err := os.Create(filepath.Join(cfg.Pkg, "attr.go"))
 	if err != nil {
 		return fmt.Errorf("creating file: %w", err)
 	}
-	defer errorsx.Close(f, &err)
+	defer errorsx.Close(genFile, &err)
 
-	if err := tmpl.Execute(f, cfg); err != nil {
+	if err := tmpl.Execute(genFile, cfg); err != nil {
 		return fmt.Errorf("executing template: %w", err)
 	}
 
 	return nil
 }
-
-var tmpl = template.Must(template.New("").Funcs(funcs).Parse(
-	`// Code generated by go-simpler.org/slog-gen. DO NOT EDIT.
-
-package {{.Pkg}}
-
-{{range .Imports -}}
-import "{{.}}"
-{{end -}}
-
-{{range $_, $attr := .Attrs}}
-func {{snakeToCamel $attr.Key}}(value {{$attr.Type}}) slog.Attr {
-	return slog.{{slogFunc $attr.Type}}("{{$attr.Key}}", value)
-}
-{{end}}`,
-))
-
-type (
-	config struct {
-		Pkg     string
-		Imports []string
-		Attrs   []attr
-	}
-	attr struct {
-		Key  string
-		Type string
-	}
-)
-
-func loadConfig(path string) (*config, error) {
-	data, err := os.ReadFile(path)
-	if err != nil {
-		return nil, fmt.Errorf("reading config: %w", err)
-	}
-
-	var cfg struct {
-		Pkg     string            `yaml:"pkg"`
-		Imports []string          `yaml:"imports"`
-		Attrs   map[string]string `yaml:"attrs"` // key:type
-	}
-	if err := yaml.Unmarshal(data, &cfg); err != nil {
-		return nil, fmt.Errorf("decoding config: %w", err)
-	}
-
-	cfg.Imports = append(cfg.Imports, "log/slog")
-	sort.Strings(cfg.Imports)
-
-	// TODO: rewrite when maps.Keys() is released.
-	keys := make([]string, 0, len(cfg.Attrs))
-	for key := range cfg.Attrs {
-		keys = append(keys, key)
-	}
-	sort.Strings(keys)
-
-	attrs := make([]attr, len(keys))
-	for i, key := range keys {
-		attrs[i] = attr{Key: key, Type: cfg.Attrs[key]}
-	}
-
-	return &config{
-		Pkg:     cfg.Pkg,
-		Imports: cfg.Imports,
-		Attrs:   attrs,
-	}, nil
-}
-
-// nolint:staticcheck // SA1019: strings.Title is deprecated but works just fine here.
-var funcs = template.FuncMap{
-	"snakeToCamel": func(s string) string {
-		parts := strings.Split(s, "_")
-		for i := range parts {
-			parts[i] = strings.Title(parts[i])
-		}
-		return strings.Join(parts, "")
-	},
-	"slogFunc": func(typ string) string {
-		switch s := strings.Title(strings.TrimPrefix(typ, "time.")); s {
-		case "String", "Int64", "Int", "Uint64", "Float64", "Bool", "Time", "Duration":
-			return s
-		default:
-			return "Any"
-		}
-	},
-}