chore: docstring test writer

Signed-off-by: Alano Terblanche <18033717+Benehiko@users.noreply.github.com>

internal/test/writer.go

@@ -4,19 +4,24 @@ import (
 	"io"
 )
 
+// WriterWithHook is an io.Writer that calls a hook function after every write.
+// This is useful for testing.
 type WriterWithHook struct {
 	actualWriter io.Writer
 	hook         func()
 }
 
-// Write implements io.Writer.
+// Write writes p to the actual writer and then calls the hook function.
 func (w *WriterWithHook) Write(p []byte) (n int, err error) {
 	defer w.hook()
 	return w.actualWriter.Write(p)
 }
 
 var _ io.Writer = (*WriterWithHook)(nil)
 
+// NewWriterWithHook returns a new WriterWithHook that still writes to the actualWriter
+// but also calls the hook function after every write.
+// The hook function is useful for testing, or waiting for a write to complete.
 func NewWriterWithHook(actualWriter io.Writer, hook func()) *WriterWithHook {
 	return &WriterWithHook{actualWriter: actualWriter, hook: hook}
 }