phase5: cli subcommand with file/stdin input and output options
This commit is contained in:
Sergey Filkin
@@ -0,0 +1,171 @@
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package cli
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import (
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"context"
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"errors"
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"flag"
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"fmt"
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"io"
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"os"
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"path/filepath"
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"strings"
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"github.com/fserg/md-to-html/internal/converter"
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webtemplate "github.com/fserg/md-to-html/web/template"
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)
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var ErrUsage = errors.New("cli usage error")
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func Run(ctx context.Context, args []string, stdin io.Reader, stdout, stderr io.Writer) error {
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if ctx == nil {
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ctx = context.Background()
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}
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if wantsHelp(args) {
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printUsage(stdout)
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return nil
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}
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normalized, err := normalizeArgs(args)
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if err != nil {
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printUsage(stderr)
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return fmt.Errorf("%w: %v", ErrUsage, err)
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}
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fs := flag.NewFlagSet("cli", flag.ContinueOnError)
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fs.SetOutput(stderr)
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var (
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output string
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title string
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useStdin bool
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)
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fs.StringVar(&output, "output", "", "output file path")
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fs.StringVar(&output, "o", "", "output file path")
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fs.StringVar(&title, "title", "", "fallback title if markdown has no headings")
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fs.BoolVar(&useStdin, "stdin", false, "read markdown from stdin")
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if err := fs.Parse(normalized); err != nil {
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printUsage(stderr)
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return fmt.Errorf("%w: %v", ErrUsage, err)
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}
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if err := ctx.Err(); err != nil {
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return err
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}
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positional := fs.Args()
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if len(positional) > 1 {
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printUsage(stderr)
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return fmt.Errorf("%w: expected a single input file or '-'", ErrUsage)
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}
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conv, err := converter.New(webtemplate.FS)
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if err != nil {
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return fmt.Errorf("init converter: %w", err)
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}
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var (
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markdown []byte
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fallbackTitle = title
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outputPath = output
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writeToStdout bool
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)
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switch {
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case useStdin || (len(positional) == 1 && positional[0] == "-"):
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markdown, err = io.ReadAll(stdin)
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if err != nil {
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return fmt.Errorf("read stdin: %w", err)
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}
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if fallbackTitle == "" {
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fallbackTitle = "Document"
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}
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writeToStdout = outputPath == ""
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case len(positional) == 1:
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inputPath := positional[0]
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markdown, err = os.ReadFile(inputPath)
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if err != nil {
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return fmt.Errorf("read %s: %w", inputPath, err)
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}
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if fallbackTitle == "" {
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fallbackTitle = strings.TrimSuffix(filepath.Base(inputPath), filepath.Ext(inputPath))
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}
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if outputPath == "" {
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outputPath = strings.TrimSuffix(inputPath, filepath.Ext(inputPath)) + ".html"
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}
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default:
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printUsage(stderr)
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return fmt.Errorf("%w: no input specified", ErrUsage)
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}
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result, err := conv.Convert(markdown, fallbackTitle)
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if err != nil {
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return fmt.Errorf("convert markdown: %w", err)
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}
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if writeToStdout {
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_, err = stdout.Write(result.HTML)
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if err != nil {
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return fmt.Errorf("write stdout: %w", err)
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}
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return nil
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}
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if err := os.WriteFile(outputPath, result.HTML, 0o644); err != nil {
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return fmt.Errorf("write %s: %w", outputPath, err)
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}
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return nil
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}
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func normalizeArgs(args []string) ([]string, error) {
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flags := make([]string, 0, len(args))
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positionals := make([]string, 0, 1)
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for i := 0; i < len(args); i++ {
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arg := args[i]
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switch {
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case arg == "--":
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positionals = append(positionals, args[i+1:]...)
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return append(flags, positionals...), nil
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case arg == "-":
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positionals = append(positionals, arg)
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case !strings.HasPrefix(arg, "-"):
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positionals = append(positionals, arg)
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case strings.HasPrefix(arg, "--output="), strings.HasPrefix(arg, "--title="), strings.HasPrefix(arg, "-o="):
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flags = append(flags, arg)
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case arg == "--output" || arg == "-o" || arg == "--title":
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if i+1 >= len(args) {
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return nil, fmt.Errorf("flag needs an argument: %s", arg)
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}
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flags = append(flags, arg, args[i+1])
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i++
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default:
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flags = append(flags, arg)
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}
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}
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return append(flags, positionals...), nil
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}
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func wantsHelp(args []string) bool {
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for _, arg := range args {
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switch arg {
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case "-h", "--help", "-help":
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return true
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}
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}
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return false
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}
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func printUsage(w io.Writer) {
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fmt.Fprint(w, `Usage: md-to-html cli [--stdin|-|<file.md>] [--output path] [--title str]
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Options:
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--stdin Read markdown from stdin
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-o, --output Output file path (default: stdout for stdin, <input>.html for file)
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--title Fallback title if markdown has no headings
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-h, --help Show this help
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`)
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}
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@@ -0,0 +1,124 @@
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package cli
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import (
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"bytes"
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"context"
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"errors"
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"os"
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"path/filepath"
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"strings"
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"testing"
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)
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func TestCLIFileToFile(t *testing.T) {
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t.Parallel()
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dir := t.TempDir()
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inputPath := filepath.Join(dir, "example.md")
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if err := os.WriteFile(inputPath, []byte("# Hello\n\nBody"), 0o644); err != nil {
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t.Fatalf("write input: %v", err)
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}
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var stdout, stderr bytes.Buffer
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if err := Run(context.Background(), []string{inputPath}, strings.NewReader(""), &stdout, &stderr); err != nil {
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t.Fatalf("run: %v", err)
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}
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outputPath := filepath.Join(dir, "example.html")
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got, err := os.ReadFile(outputPath)
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if err != nil {
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t.Fatalf("read output: %v", err)
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}
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if !bytes.Contains(got, []byte("<!DOCTYPE html>")) {
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t.Fatalf("output missing doctype: %s", got)
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}
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if stdout.Len() != 0 {
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t.Fatalf("stdout = %q, want empty", stdout.String())
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}
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if stderr.Len() != 0 {
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t.Fatalf("stderr = %q, want empty", stderr.String())
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}
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}
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func TestCLIStdin(t *testing.T) {
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t.Parallel()
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stdin := strings.NewReader("# Привет\n\nТекст")
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var stdout, stderr bytes.Buffer
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if err := Run(context.Background(), []string{"--stdin"}, stdin, &stdout, &stderr); err != nil {
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t.Fatalf("run: %v", err)
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}
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if !strings.Contains(stdout.String(), "<!DOCTYPE html>") {
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t.Fatalf("stdout missing doctype: %s", stdout.String())
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}
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if stderr.Len() != 0 {
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t.Fatalf("stderr = %q, want empty", stderr.String())
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}
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}
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func TestCLIOutputFlag(t *testing.T) {
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t.Parallel()
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dir := t.TempDir()
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inputPath := filepath.Join(dir, "example.md")
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outputPath := filepath.Join(dir, "custom.html")
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if err := os.WriteFile(inputPath, []byte("Plain text"), 0o644); err != nil {
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t.Fatalf("write input: %v", err)
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}
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var stdout, stderr bytes.Buffer
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if err := Run(context.Background(), []string{inputPath, "-o", outputPath}, strings.NewReader(""), &stdout, &stderr); err != nil {
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t.Fatalf("run: %v", err)
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}
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if _, err := os.Stat(outputPath); err != nil {
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t.Fatalf("stat output: %v", err)
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}
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}
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func TestCLITitle(t *testing.T) {
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t.Parallel()
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var stdout, stderr bytes.Buffer
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if err := Run(context.Background(), []string{"--stdin", "--title", "Custom"}, strings.NewReader(""), &stdout, &stderr); err != nil {
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t.Fatalf("run: %v", err)
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}
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if !strings.Contains(stdout.String(), "<title>Custom</title>") {
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t.Fatalf("stdout missing title: %s", stdout.String())
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}
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}
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func TestCLINoInput(t *testing.T) {
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t.Parallel()
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var stdout, stderr bytes.Buffer
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err := Run(context.Background(), nil, strings.NewReader(""), &stdout, &stderr)
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if err == nil {
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t.Fatal("expected error, got nil")
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}
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if !errors.Is(err, ErrUsage) {
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t.Fatalf("error = %v, want ErrUsage", err)
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}
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if !strings.Contains(stderr.String(), "Usage: md-to-html cli") {
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t.Fatalf("stderr missing usage: %s", stderr.String())
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}
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}
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func TestCLIMissingFile(t *testing.T) {
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t.Parallel()
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var stdout, stderr bytes.Buffer
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err := Run(context.Background(), []string{"missing.md"}, strings.NewReader(""), &stdout, &stderr)
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if err == nil {
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t.Fatal("expected error, got nil")
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}
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if errors.Is(err, ErrUsage) {
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t.Fatalf("error = %v, did not want ErrUsage", err)
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}
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if stdout.Len() != 0 {
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t.Fatalf("stdout = %q, want empty", stdout.String())
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}
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}
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