feat: refactor test helpers

Better organize and allow for re-use across packages.

Signed-off-by: Brian McGee <brian@bmcgee.ie>

internal/cli/format_test.go

@@ -1,105 +1,21 @@
 package cli
 
 import (
-	"fmt"
-	"io"
-	"os"
-	"path/filepath"
 	"testing"
 
+	"git.numtide.com/numtide/treefmt/internal/test"
+
 	"git.numtide.com/numtide/treefmt/internal/format"
-	"github.com/BurntSushi/toml"
-	"github.com/alecthomas/kong"
-	cp "github.com/otiai10/copy"
-	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 )
 
-func writeConfig(t *testing.T, path string, cfg format.Config) {
-	t.Helper()
-	f, err := os.Create(path)
-	if err != nil {
-		t.Fatalf("failed to create a new config file: %v", err)
-	}
-	encoder := toml.NewEncoder(f)
-	if err = encoder.Encode(cfg); err != nil {
-		t.Fatalf("failed to write to config file: %v", err)
-	}
-}
-
-func newKong(t *testing.T, cli interface{}, options ...kong.Option) *kong.Kong {
-	t.Helper()
-	options = append([]kong.Option{
-		kong.Name("test"),
-		kong.Exit(func(int) {
-			t.Helper()
-			t.Fatalf("unexpected exit()")
-		}),
-	}, options...)
-	parser, err := kong.New(cli, options...)
-	assert.NoError(t, err)
-	return parser
-}
-
-func tempFile(t *testing.T, path string) *os.File {
-	t.Helper()
-	file, err := os.Create(path)
-	if err != nil {
-		t.Fatalf("failed to create temporary file: %v", err)
-	}
-	return file
-}
-
-func cmd(t *testing.T, args ...string) ([]byte, error) {
-	t.Helper()
-
-	// create a new kong context
-	p := newKong(t, &Cli)
-	ctx, err := p.Parse(args)
-	if err != nil {
-		return nil, err
-	}
-
-	tempDir := t.TempDir()
-	tempOut := tempFile(t, filepath.Join(tempDir, "combined_output"))
-
-	// capture standard outputs before swapping them
-	stdout := os.Stdout
-	stderr := os.Stderr
-
-	// swap them temporarily
-	os.Stdout = tempOut
-	os.Stderr = tempOut
-
-	// run the command
-	if err = ctx.Run(); err != nil {
-		return nil, err
-	}
-
-	// reset and read the temporary output
-	if _, err = tempOut.Seek(0, 0); err != nil {
-		return nil, fmt.Errorf("%w: failed to reset temp output for reading", err)
-	}
-
-	out, err := io.ReadAll(tempOut)
-	if err != nil {
-		return nil, fmt.Errorf("%w: failed to read temp output", err)
-	}
-
-	// swap outputs back
-	os.Stdout = stdout
-	os.Stderr = stderr
-
-	return out, nil
-}
-
 func TestAllowMissingFormatter(t *testing.T) {
 	as := require.New(t)
 
 	tempDir := t.TempDir()
 	configPath := tempDir + "/treefmt.toml"
 
-	writeConfig(t, configPath, format.Config{
+	test.WriteConfig(t, configPath, format.Config{
 		Formatters: map[string]*format.Formatter{
 			"foo-fmt": {
 				Command: "foo-fmt",
@@ -117,12 +33,10 @@ func TestAllowMissingFormatter(t *testing.T) {
 func TestSpecifyingFormatters(t *testing.T) {
 	as := require.New(t)
 
-	tempDir := t.TempDir()
+	tempDir := test.TempExamples(t)
 	configPath := tempDir + "/treefmt.toml"
 
-	as.NoError(cp.Copy("../../test/examples", tempDir), "failed to copy test data to temp dir")
-
-	writeConfig(t, configPath, format.Config{
+	test.WriteConfig(t, configPath, format.Config{
 		Formatters: map[string]*format.Formatter{
 			"elm": {
 				Command:  "echo",

internal/cli/helpers_test.go

@@ -0,0 +1,70 @@
+package cli
+
+import (
+	"fmt"
+	"io"
+	"os"
+	"path/filepath"
+	"testing"
+
+	"git.numtide.com/numtide/treefmt/internal/test"
+	"github.com/alecthomas/kong"
+	"github.com/stretchr/testify/require"
+)
+
+func newKong(t *testing.T, cli interface{}, options ...kong.Option) *kong.Kong {
+	t.Helper()
+	options = append([]kong.Option{
+		kong.Name("test"),
+		kong.Exit(func(int) {
+			t.Helper()
+			t.Fatalf("unexpected exit()")
+		}),
+	}, options...)
+	parser, err := kong.New(cli, options...)
+	require.NoError(t, err)
+	return parser
+}
+
+func cmd(t *testing.T, args ...string) ([]byte, error) {
+	t.Helper()
+
+	// create a new kong context
+	p := newKong(t, &Cli)
+	ctx, err := p.Parse(args)
+	if err != nil {
+		return nil, err
+	}
+
+	tempDir := t.TempDir()
+	tempOut := test.TempFile(t, filepath.Join(tempDir, "combined_output"))
+
+	// capture standard outputs before swapping them
+	stdout := os.Stdout
+	stderr := os.Stderr
+
+	// swap them temporarily
+	os.Stdout = tempOut
+	os.Stderr = tempOut
+
+	// run the command
+	if err = ctx.Run(); err != nil {
+		return nil, err
+	}
+
+	// reset and read the temporary output
+	if _, err = tempOut.Seek(0, 0); err != nil {
+		return nil, fmt.Errorf("%w: failed to reset temp output for reading", err)
+	}
+
+	out, err := io.ReadAll(tempOut)
+	if err != nil {
+		return nil, fmt.Errorf("%w: failed to read temp output", err)
+	}
+
+	// swap outputs back
+	os.Stdout = stdout
+	os.Stderr = stderr
+
+	return out, nil
+}

internal/test/temp.go

@@ -0,0 +1,38 @@
+package test
+
+import (
+	"os"
+	"testing"
+
+	"git.numtide.com/numtide/treefmt/internal/format"
+	"github.com/BurntSushi/toml"
+	cp "github.com/otiai10/copy"
+	"github.com/stretchr/testify/require"
+)
+
+func WriteConfig(t *testing.T, path string, cfg format.Config) {
+	t.Helper()
+	f, err := os.Create(path)
+	if err != nil {
+		t.Fatalf("failed to create a new config file: %v", err)
+	}
+	encoder := toml.NewEncoder(f)
+	if err = encoder.Encode(cfg); err != nil {
+		t.Fatalf("failed to write to config file: %v", err)
+	}
+}
+
+func TempExamples(t *testing.T) string {
+	tempDir := t.TempDir()
+	require.NoError(t, cp.Copy("../../test/examples", tempDir), "failed to copy test data to temp dir")
+	return tempDir
+}
+
+func TempFile(t *testing.T, path string) *os.File {
+	t.Helper()
+	file, err := os.Create(path)
+	if err != nil {
+		t.Fatalf("failed to create temporary file: %v", err)
+	}
+	return file
+}