feat: add flag to write go test output to a file (#134)

internal/app/app.go

@@ -10,6 +10,8 @@ import (
 )
 
 type Options struct {
+	// Output is used to write the final output, such as the tables, summary, etc.
+	Output io.Writer
 	// DisableColor will disable all colors.
 	DisableColor bool
 	// Format will set the output format for tables.
@@ -26,12 +28,16 @@ type Options struct {
 	SummaryTableOptions SummaryTableOptions
 
 	// FollowOutput will follow the raw output as go test is running.
-	FollowOutput        bool
+	FollowOutput        bool           // Output to stdout
+	FollowOutputWriter  io.WriteCloser // Output to a file, takes precedence over FollowOutput
 	FollowOutputVerbose bool
 
 	// Progress will print a single summary line for each package once the package has completed.
 	// Useful for long running test suites. Maybe used with FollowOutput or on its own.
-	Progress bool
+	//
+	// This will output to stdout.
+	Progress       bool
+	ProgressOutput io.Writer
 
 	// DisableTableOutput will disable all table output. This is used for testing.
 	DisableTableOutput bool
@@ -44,7 +50,7 @@ type Options struct {
 	Compare string
 }
 
-func Run(w io.Writer, option Options) (int, error) {
+func Run(option Options) (int, error) {
 	var reader io.ReadCloser
 	var err error
 	if option.FileName != "" {
@@ -58,12 +64,17 @@ func Run(w io.Writer, option Options) (int, error) {
 	}
 	defer reader.Close()
 
+	if option.FollowOutputWriter != nil {
+		defer option.FollowOutputWriter.Close()
+	}
+
 	summary, err := parse.Process(
 		reader,
 		parse.WithFollowOutput(option.FollowOutput),
 		parse.WithFollowVersboseOutput(option.FollowOutputVerbose),
-		parse.WithWriter(w),
+		parse.WithWriter(option.FollowOutputWriter),
 		parse.WithProgress(option.Progress),
+		parse.WithProgressOutput(option.ProgressOutput),
 	)
 	if err != nil {
 		return 1, err
@@ -74,7 +85,7 @@ func Run(w io.Writer, option Options) (int, error) {
 	// Useful for tests that don't need tparse table output. Very useful for testing output from
 	// [parse.Process]
 	if !option.DisableTableOutput {
-		display(w, summary, option)
+		display(option.Output, summary, option)
 	}
 	return summary.ExitCode(), nil
 }

internal/utils/utils.go

@@ -1,6 +1,7 @@
 package utils
 
 import (
+	"io"
 	"sort"
 	"strings"
 )
@@ -45,3 +46,14 @@ func minimum(a, b int) int {
 	}
 	return b
 }
+
+// DiscardCloser is an io.Writer that implements io.Closer by doing nothing.
+//
+// https://github.com/golang/go/issues/22823
+type WriteNopCloser struct {
+	io.Writer
+}
+
+func (WriteNopCloser) Close() error {
+	return nil
+}

main.go

@@ -4,34 +4,37 @@ import (
 	"errors"
 	"flag"
 	"fmt"
+	"io"
 	"log"
 	"os"
 
 	"github.com/mfridman/buildversion"
 	"github.com/mfridman/tparse/internal/app"
+	"github.com/mfridman/tparse/internal/utils"
 	"github.com/mfridman/tparse/parse"
 )
 
 // Flags.
 var (
-	vPtr           = flag.Bool("v", false, "")
-	versionPtr     = flag.Bool("version", false, "")
-	hPtr           = flag.Bool("h", false, "")
-	helpPtr        = flag.Bool("help", false, "")
-	allPtr         = flag.Bool("all", false, "")
-	passPtr        = flag.Bool("pass", false, "")
-	skipPtr        = flag.Bool("skip", false, "")
-	showNoTestsPtr = flag.Bool("notests", false, "")
-	smallScreenPtr = flag.Bool("smallscreen", false, "")
-	noColorPtr     = flag.Bool("nocolor", false, "")
-	slowPtr        = flag.Int("slow", 0, "")
-	fileNamePtr    = flag.String("file", "", "")
-	formatPtr      = flag.String("format", "", "")
-	followPtr      = flag.Bool("follow", false, "")
-	sortPtr        = flag.String("sort", "name", "")
-	progressPtr    = flag.Bool("progress", false, "")
-	comparePtr     = flag.String("compare", "", "")
-	trimPathPtr    = flag.String("trimpath", "", "")
+	vPtr            = flag.Bool("v", false, "")
+	versionPtr      = flag.Bool("version", false, "")
+	hPtr            = flag.Bool("h", false, "")
+	helpPtr         = flag.Bool("help", false, "")
+	allPtr          = flag.Bool("all", false, "")
+	passPtr         = flag.Bool("pass", false, "")
+	skipPtr         = flag.Bool("skip", false, "")
+	showNoTestsPtr  = flag.Bool("notests", false, "")
+	smallScreenPtr  = flag.Bool("smallscreen", false, "")
+	noColorPtr      = flag.Bool("nocolor", false, "")
+	slowPtr         = flag.Int("slow", 0, "")
+	fileNamePtr     = flag.String("file", "", "")
+	formatPtr       = flag.String("format", "", "")
+	followPtr       = flag.Bool("follow", false, "")
+	followOutputPtr = flag.String("follow-output", "", "")
+	sortPtr         = flag.String("sort", "name", "")
+	progressPtr     = flag.Bool("progress", false, "")
+	comparePtr      = flag.String("compare", "", "")
+	trimPathPtr     = flag.String("trimpath", "", "")
 	// Undocumented flags
 	followVerbosePtr = flag.Bool("follow-verbose", false, "")
 
@@ -57,7 +60,8 @@ Options:
     -nocolor       Disable all colors. (NO_COLOR also supported)
     -format        The output format for tables [basic, plain, markdown]. Default is basic.
     -file          Read test output from a file.
-    -follow        Follow raw output as go test is running.
+    -follow        Follow raw output from go test to stdout.
+    -follow-output Write raw output from go test to a file (takes precedence over -follow).
     -progress      Print a single summary line for each package. Useful for long running test suites.
     -compare       Compare against a previous test output file. (experimental)
     -trimpath      Remove path prefix from package names in output, simplifying their display.
@@ -95,7 +99,7 @@ func main() {
 			format = app.OutputFormatPlain
 		}
 	default:
-		fmt.Fprintf(os.Stderr, "invalid option:%q. The -format flag must be one of: basic, plain or markdown", *formatPtr)
+		fmt.Fprintf(os.Stderr, "invalid option:%q. The -format flag must be one of: basic, plain or markdown\n", *formatPtr)
 		return
 	}
 	var sorter parse.PackageSorter
@@ -120,10 +124,28 @@ func main() {
 	if _, ok := os.LookupEnv("NO_COLOR"); ok || *noColorPtr {
 		disableColor = true
 	}
+
+	var followOutput io.WriteCloser
+	switch {
+	case *followOutputPtr != "":
+		var err error
+		followOutput, err = os.Create(*followOutputPtr)
+		if err != nil {
+			fmt.Fprintln(os.Stderr, err)
+			return
+		}
+	case *followPtr:
+		followOutput = os.Stdout
+	default:
+		// If no follow flags are set, we should not write to followOutput.
+		followOutput = utils.WriteNopCloser{Writer: io.Discard}
+	}
 	// TODO(mf): we should marry the options with the flags to avoid having to do this.
 	options := app.Options{
+		Output:              os.Stdout,
 		DisableColor:        disableColor,
 		FollowOutput:        *followPtr,
+		FollowOutputWriter:  followOutput,
 		FollowOutputVerbose: *followVerbosePtr,
 		FileName:            *fileNamePtr,
 		TestTableOptions: app.TestTableOptions{
@@ -137,16 +159,17 @@ func main() {
 			Trim:     *smallScreenPtr,
 			TrimPath: *trimPathPtr,
 		},
-		Format:      format,
-		Sorter:      sorter,
-		ShowNoTests: *showNoTestsPtr,
-		Progress:    *progressPtr,
-		Compare:     *comparePtr,
+		Format:         format,
+		Sorter:         sorter,
+		ShowNoTests:    *showNoTestsPtr,
+		Progress:       *progressPtr,
+		ProgressOutput: os.Stdout,
+		Compare:        *comparePtr,
 
 		// Do not expose publicly.
 		DisableTableOutput: false,
 	}
-	exitCode, err := app.Run(os.Stdout, options)
+	exitCode, err := app.Run(options)
 	if err != nil {
 		msg := err.Error()
 		if errors.Is(err, parse.ErrNotParsable) {

parse/process.go

@@ -109,7 +109,7 @@ func Process(r io.Reader, optionsFunc ...OptionsFunc) (*GoTestSummary, error) {
 		// Progress is a special case of follow, where we only print the
 		// progress of the test suite, but not the output.
 		if option.progress && option.w != nil {
-			printProgress(option.w, e, summary.Packages)
+			printProgress(option.progressOutput, e, summary.Packages)
 		}
 
 		summary.AddEvent(e)

parse/process_options.go

@@ -9,7 +9,9 @@ type options struct {
 	follow        bool
 	followVerbose bool
 	debug         bool
-	progress      bool
+
+	progress       bool
+	progressOutput io.Writer
 }
 
 type OptionsFunc func(o *options)
@@ -33,3 +35,7 @@ func WithDebug() OptionsFunc {
 func WithProgress(b bool) OptionsFunc {
 	return func(o *options) { o.progress = b }
 }
+
+func WithProgressOutput(w io.Writer) OptionsFunc {
+	return func(o *options) { o.progressOutput = w }
+}

tests/follow_test.go

@@ -10,6 +10,7 @@ import (
 	"github.com/stretchr/testify/assert"
 
 	"github.com/mfridman/tparse/internal/app"
+	"github.com/mfridman/tparse/internal/utils"
 	"github.com/mfridman/tparse/parse"
 )
 
@@ -35,15 +36,16 @@ func TestFollow(t *testing.T) {
 		}
 		for _, tc := range tt {
 			t.Run(tc.fileName, func(t *testing.T) {
+				buf := bytes.NewBuffer(nil)
 				inputFile := filepath.Join(base, tc.fileName+".jsonl")
 				options := app.Options{
 					FileName:            inputFile,
 					FollowOutput:        true,
+					FollowOutputWriter:  utils.WriteNopCloser{Writer: buf},
 					FollowOutputVerbose: true,
 					DisableTableOutput:  true,
 				}
-				var buf bytes.Buffer
-				gotExitCode, err := app.Run(&buf, options)
+				gotExitCode, err := app.Run(options)
 				if err != nil && !errors.Is(err, tc.err) {
 					t.Fatal(err)
 				}
@@ -70,14 +72,15 @@ func TestFollow(t *testing.T) {
 		}
 		for _, tc := range tt {
 			t.Run(tc.fileName, func(t *testing.T) {
+				buf := bytes.NewBuffer(nil)
 				inputFile := filepath.Join(base, tc.fileName+".jsonl")
 				options := app.Options{
 					FileName:           inputFile,
 					FollowOutput:       true,
+					FollowOutputWriter: utils.WriteNopCloser{Writer: buf},
 					DisableTableOutput: true,
 				}
-				var buf bytes.Buffer
-				gotExitCode, err := app.Run(&buf, options)
+				gotExitCode, err := app.Run(options)
 				if err != nil && !errors.Is(err, tc.err) {
 					t.Fatal(err)
 				}