Remove temp file on test completion

Signed-off-by: Sean Holcomb <seanholcomb@gmail.com>

pkg/filemanager/filemanager_test.go

@@ -14,25 +14,33 @@ import (
 
 func Test_NewFileManager(t *testing.T) {
 	t.Run("file system", func(t *testing.T) {
+		// Create File Manager
 		tmpPath := filepath.Join(os.TempDir(), fmt.Sprintf("opencost-test-file-manager-%d", rand.Int31()))
+		defer os.Remove(tmpPath) // remove managed file on completion to ensure it does not exist for next run
 		fm, err := NewFileManager(tmpPath)
 		require.NoError(t, err)
 
+		// Attempt to download Managed file into a new file, this should fail because managed file has not been initalized
 		downloadFile, err := os.CreateTemp("", "opencost-test-file-manager-*")
 		require.NoError(t, err)
 		err = fm.Download(context.TODO(), downloadFile)
 		require.ErrorIs(t, err, ErrNotFound)
 
+		// Create a file and add content to it
 		uploadFile, err := os.CreateTemp("", "opencost-test-file-manager-*")
 		require.NoError(t, err)
 		_, err = uploadFile.WriteString("test-content")
 		require.NoError(t, err)
-		require.NoError(t, err)
+
+		// Upload file to managed file
 		err = fm.Upload(context.TODO(), uploadFile)
 		require.NoError(t, err)
 
+		// Download managed file to original file
 		err = fm.Download(context.TODO(), downloadFile)
 		require.NoError(t, err)
+
+		// Check that content matches
 		_, err = downloadFile.Seek(0, io.SeekStart)
 		require.NoError(t, err)
 		data, err := io.ReadAll(downloadFile)