Add file creation handling and tests in SampleUpdater #67

The code now checks if the specified file exists before appending a message. If it doesn't exist, it tries to create it, handling related errors accordingly. Corresponding tests to verify the new functionality have also been added, effectively ensuring its correct operation.

The failure to update spam for non-existing file was a side effect from duplication check #63

fix test typo from prev commit

app/bot/sample_updater.go

@@ -30,6 +30,14 @@ func (s *SampleUpdater) Reader() (io.ReadCloser, error) {
 
 // Append a message to the file, preventing duplicates
 func (s *SampleUpdater) Append(msg string) error {
+	// if file does not exist, create it
+	if _, err := os.Stat(s.fileName); os.IsNotExist(err) {
+		if _, err = os.Create(s.fileName); err != nil {
+			return fmt.Errorf("failed to create %s: %w", s.fileName, err)
+		}
+	}
+
+	// check if the message is already in the file
 	fh, err := os.Open(s.fileName)
 	if err != nil {
 		return fmt.Errorf("failed to open %s: %w", s.fileName, err)
@@ -44,6 +52,7 @@ func (s *SampleUpdater) Append(msg string) error {
 		}
 	}
 
+	// append the message to the file
 	fh, err = os.OpenFile(s.fileName, os.O_APPEND|os.O_WRONLY|os.O_CREATE, 0o644) //nolint:gosec // keep it readable by all
 	if err != nil {
 		return fmt.Errorf("failed to open %s: %w", s.fileName, err)

app/bot/sample_updater_test.go

@@ -3,6 +3,7 @@ package bot
 import (
 	"io"
 	"os"
+	"path/filepath"
 	"testing"
 
 	"github.com/stretchr/testify/assert"
@@ -72,6 +73,24 @@ func TestSampleUpdater(t *testing.T) {
 		assert.Equal(t, "Test message second line third line\n", string(content))
 	})
 
+	t.Run("no file", func(t *testing.T) {
+		dir := os.TempDir()
+		file := filepath.Join(dir, "non-existent-samples.txt")
+		defer os.Remove(file)
+
+		updater := NewSampleUpdater(file)
+		err := updater.Append("Test message")
+		assert.NoError(t, err)
+
+		reader, err := updater.Reader()
+		require.NoError(t, err)
+		defer reader.Close()
+
+		content, err := io.ReadAll(reader)
+		assert.NoError(t, err)
+		assert.Equal(t, "Test message\n", string(content))
+	})
+
 	t.Run("unhappy path", func(t *testing.T) {
 		updater := NewSampleUpdater("/tmp/non-existent/samples.txt")
 		err := updater.Append("Test message")