Feat/config/generate (#136)

Implement config command & generate verb to write default configuration to file or stdout.

cli/cmd/configgenerate_test.go

@@ -0,0 +1,70 @@
+package cmd
+
+import (
+	"bytes"
+	"testing"
+
+	"github.com/edgelesssys/constellation/cli/file"
+	"github.com/edgelesssys/constellation/internal/config"
+	"github.com/edgelesssys/constellation/internal/constants"
+	"github.com/spf13/afero"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+	"gopkg.in/yaml.v3"
+)
+
+func defaultConfigAsYAML(t *testing.T) string {
+	var readBuffer bytes.Buffer
+	require.NoError(t, yaml.NewEncoder(&readBuffer).Encode(config.Default()))
+	return readBuffer.String()
+}
+
+func TestConfigGenerateDefault(t *testing.T) {
+	assert := assert.New(t)
+	require := require.New(t)
+
+	fileHandler := file.NewHandler(afero.NewMemMapFs())
+	cmd := newConfigGenerateCmd()
+
+	require.NoError(configGenerate(cmd, fileHandler))
+
+	readYAML, err := fileHandler.Read(constants.ConfigFilename)
+	assert.NoError(err)
+	assert.Equal(defaultConfigAsYAML(t), string(readYAML))
+}
+
+func TestConfigGenerateDefaultExists(t *testing.T) {
+	require := require.New(t)
+
+	fileHandler := file.NewHandler(afero.NewMemMapFs())
+	require.NoError(fileHandler.Write(constants.ConfigFilename, []byte("foobar"), file.OptNone))
+	cmd := newConfigGenerateCmd()
+
+	require.Error(configGenerate(cmd, fileHandler))
+}
+
+func TestConfigGenerateFileFlagRemoved(t *testing.T) {
+	require := require.New(t)
+
+	fileHandler := file.NewHandler(afero.NewMemMapFs())
+	cmd := newConfigGenerateCmd()
+	cmd.ResetFlags()
+
+	require.Error(configGenerate(cmd, fileHandler))
+}
+
+func TestConfigGenerateStdOut(t *testing.T) {
+	assert := assert.New(t)
+	require := require.New(t)
+
+	fileHandler := file.NewHandler(afero.NewMemMapFs())
+
+	var outBuffer bytes.Buffer
+	cmd := newConfigGenerateCmd()
+	cmd.SetOut(&outBuffer)
+	require.NoError(cmd.Flags().Set("file", "-"))
+
+	require.NoError(configGenerate(cmd, fileHandler))
+
+	assert.Equal(defaultConfigAsYAML(t), outBuffer.String())
+}