Adding data SaveToWriter

Signed-off-by: apostasie <[email protected]>

Author: apostasie

mod/tigron/expect/doc.md

@@ -131,7 +131,7 @@ func TestMyThing(t *testing.T) {
     myTest.Command = test.Custom("ls")
 
     // Set your expectations
-    myTest.Expected = test.Expects(0, nil, func(stdout, info string, t tig.T){
+    myTest.Expected = test.Expects(0, nil, func(stdout string, t tig.T){
         t.Helper()
         // Bla bla, do whatever advanced stuff and some asserts
     })
@@ -143,7 +143,7 @@ func TestMyThing(t *testing.T) {
 // You can of course generalize your comparator into a generator if it is going to be useful repeatedly
 
 func MyComparatorGenerator(param1, param2 any) test.Comparator {
-    return func(stdout, info string, t tig.T) {
+    return func(stdout string, t tig.T) {
         t.Helper()
         // Do your thing...
         // ...
@@ -155,10 +155,6 @@ func MyComparatorGenerator(param1, param2 any) test.Comparator {
 You can now pass along `MyComparator(comparisonString)` as the third parameter of `test.Expects`, or compose it with
 other comparators using `expect.All(MyComparator(comparisonString), OtherComparator(somethingElse))`
 
-Note that you have access to an opaque `info` string, that provides a brief formatted header message that assert
-will use in case of failure to provide context on the error.
-You may of course ignore it and write your own message.
-
 ### Advanced expectations
 
 You may want to have expectations that contain a certain piece of data that is being used in the command or at
@@ -180,6 +176,7 @@ import (
 
     "gotest.tools/v3/assert"
 
+    "github.com/containerd/nerdctl/mod/tigron/tig"
     "github.com/containerd/nerdctl/mod/tigron/test"
 )
 

mod/tigron/test/data.go

@@ -19,6 +19,7 @@ package test
 import (
 	"crypto/sha256"
 	"fmt"
+	"io"
 	"os"
 	"path/filepath"
 	"regexp"
@@ -110,7 +111,42 @@ func (tp *temp) Save(value string, key ...string) string {
 	assertive.ErrorIsNil(
 		assertive.WithSilentSuccess(tp.t),
 		err,
-		fmt.Sprintf("Saving file %q must succeed", filepath.Join(key...)),
+		fmt.Sprintf("Saving file %q must succeed", pth),
+	)
+
+	return pth
+}
+
+func (tp *temp) SaveToWriter(writer func(file io.Writer) error, key ...string) string {
+	tp.t.Helper()
+
+	tp.Dir(key[:len(key)-1]...)
+
+	pth := filepath.Join(append([]string{tp.tempDir}, key...)...)
+	silentT := assertive.WithSilentSuccess(tp.t)
+
+	//nolint:gosec // it is fine
+	file, err := os.OpenFile(pth, os.O_CREATE, FilePermissionsDefault)
+	assertive.ErrorIsNil(
+		silentT,
+		err,
+		fmt.Sprintf("Opening file %q must succeed", pth),
+	)
+
+	defer func() {
+		err = file.Close()
+		assertive.ErrorIsNil(
+			silentT,
+			err,
+			fmt.Sprintf("Closing file %q must succeed", pth),
+		)
+	}()
+
+	err = writer(file)
+	assertive.ErrorIsNil(
+		silentT,
+		err,
+		fmt.Sprintf("Filewriter failed while attempting to write to %q", pth),
 	)
 
 	return pth

mod/tigron/test/interfaces.go

@@ -40,6 +40,9 @@ type DataTemp interface {
 	// Save will store the content in the file, ensuring parent dir exists, and return the path.
 	// Asserts on failure.
 	Save(data string, key ...string) string
+	// SaveWithFunc allows to directly manipulate the fd.
+	// This is particularly useful for encoding functions (pem.Encode) that expect a file-descriptor
+	SaveToWriter(writer func(file io.Writer) error, key ...string) string
 	// Path will return the absolute path for the asset, whether it exists or not.
 	Path(key ...string) string
 	// Exists asserts that the object exist.