test convoluted arg parsing

cmd/slackdump/internal/diag/encrypt.go

@@ -131,15 +131,15 @@ func initRecipient() error {
 }
 
 func runEncrypt(ctx context.Context, cmd *base.Command, args []string) error {
-	in, out, err := parseArgs(args)
+	in, out, arm, err := parseArgs(args)
 	if err != nil {
 		return err
 	}
 	defer in.Close()
 	defer out.Close()
 
 	var w io.Writer = out
-	if gArm {
+	if arm || gArm {
 		// arm if requested
 		aw, err := armor.Encode(out, "PGP MESSAGE", nil)
 		if err != nil {
@@ -170,49 +170,49 @@ func runEncrypt(ctx context.Context, cmd *base.Command, args []string) error {
 //     the output is a file, if it's not a "-" otherwise stdout.
 //  4. if more than two arguments are given, it's an error
 //  5. if output is stdout, arm the output automatically
-func parseArgs(args []string) (in io.ReadCloser, out io.WriteCloser, err error) {
+func parseArgs(args []string) (in io.ReadCloser, out io.WriteCloser, arm bool, err error) {
 
 	switch len(args) {
 	case 0:
 		in = os.Stdin
 		out = os.Stdout
-		gArm = true
+		arm = true
 	case 1:
 		if args[0] == "-" {
 			in = os.Stdin
 		} else {
 			in, err = os.Open(args[0])
 			if err != nil {
 				base.SetExitStatus(base.SApplicationError)
-				return nil, nil, err
+				return nil, nil, false, err
 			}
 		}
 		out = os.Stdout
-		gArm = true
+		arm = true
 	case 2:
 		if args[0] == "-" {
 			in = os.Stdin
 		} else {
 			in, err = os.Open(args[0])
 			if err != nil {
 				base.SetExitStatus(base.SApplicationError)
-				return nil, nil, err
+				return nil, nil, false, err
 			}
 		}
 		if args[1] == "-" {
 			out = os.Stdout
-			gArm = true
+			arm = true
 		} else {
 			out, err = os.Create(args[1])
 			if err != nil {
 				in.Close()
 				base.SetExitStatus(base.SApplicationError)
-				return nil, nil, err
+				return nil, nil, false, err
 			}
 		}
 	default:
 		base.SetExitStatus(base.SInvalidParameters)
-		return nil, nil, errors.New("invalid number of arguments")
+		return nil, nil, false, errors.New("invalid number of arguments")
 	}
-	return in, out, nil
+	return in, out, arm, nil
 }

cmd/slackdump/internal/diag/encrypt_test.go

@@ -0,0 +1,84 @@
+package diag
+
+import (
+	"os"
+	"path/filepath"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func Test_parseArgs(t *testing.T) {
+	t.Run("no args", func(t *testing.T) {
+		in, out, arm, err := parseArgs([]string{})
+		require.NoError(t, err)
+		assert.Equal(t, os.Stdin, in)
+		assert.Equal(t, os.Stdout, out)
+		assert.True(t, arm)
+	})
+	t.Run("one arg", func(t *testing.T) {
+		in, out, arm, err := parseArgs([]string{"-"})
+		require.NoError(t, err)
+		assert.Equal(t, os.Stdin, in)
+		assert.Equal(t, os.Stdout, out)
+		assert.True(t, arm)
+	})
+	t.Run("two args", func(t *testing.T) {
+		in, out, arm, err := parseArgs([]string{"-", "-"})
+		require.NoError(t, err)
+		assert.Equal(t, os.Stdin, in)
+		assert.Equal(t, os.Stdout, out)
+		assert.True(t, arm)
+	})
+	t.Run("two args, first is file", func(t *testing.T) {
+		dir := t.TempDir()
+		f, _ := os.Create(filepath.Join(dir, "foo"))
+		f.Close()
+
+		in, out, arm, err := parseArgs([]string{filepath.Join(dir, "foo"), "-"})
+		require.NoError(t, err)
+		assert.Equal(t, os.Stdout, out)
+		assert.True(t, arm)
+
+		if inf, ok := in.(*os.File); ok {
+			assert.Equal(t, filepath.Join(dir, "foo"), inf.Name())
+		} else {
+			t.Errorf("input is not a file")
+		}
+	})
+	t.Run("two args, second is file", func(t *testing.T) {
+		dir := t.TempDir()
+		in, out, arm, err := parseArgs([]string{"-", filepath.Join(dir, "bar")})
+		require.NoError(t, err)
+		assert.Equal(t, os.Stdin, in)
+		assert.False(t, arm)
+
+		if outf, ok := out.(*os.File); ok {
+			assert.Equal(t, filepath.Join(dir, "bar"), outf.Name())
+		} else {
+			t.Errorf("output is not a file")
+		}
+	})
+	t.Run("two args, both are files", func(t *testing.T) {
+		dir := t.TempDir()
+		f, _ := os.Create(filepath.Join(dir, "foo"))
+		f.Close()
+
+		in, out, arm, err := parseArgs([]string{filepath.Join(dir, "foo"), filepath.Join(dir, "bar")})
+		require.NoError(t, err)
+		assert.False(t, arm)
+
+		if inf, ok := in.(*os.File); ok {
+			assert.Equal(t, filepath.Join(dir, "foo"), inf.Name())
+		} else {
+			t.Errorf("input is not a file")
+		}
+
+		if outf, ok := out.(*os.File); ok {
+			assert.Equal(t, filepath.Join(dir, "bar"), outf.Name())
+		} else {
+			t.Errorf("output is not a file")
+		}
+	})
+}