Call helm dependency update when so instructed [#25]

As with Lint, I have no idea whether the --namespace flag actually
matters here. I don't think it will hurt, though!

internal/run/depupdate.go

@@ -0,0 +1,44 @@
+package run
+
+import (
+	"fmt"
+)
+
+// DepUpdate is an execution step that calls `helm dependency update` when executed.
+type DepUpdate struct {
+	Chart string
+	cmd   cmd
+}
+
+// Execute executes the `helm upgrade` command.
+func (d *DepUpdate) Execute(_ Config) error {
+	return d.cmd.Run()
+}
+
+// Prepare gets the DepUpdate ready to execute.
+func (d *DepUpdate) Prepare(cfg Config) error {
+	if d.Chart == "" {
+		return fmt.Errorf("chart is required")
+	}
+
+	args := make([]string, 0)
+
+	if cfg.Namespace != "" {
+		args = append(args, "--namespace", cfg.Namespace)
+	}
+	if cfg.Debug {
+		args = append(args, "--debug")
+	}
+
+	args = append(args, "dependency", "update", d.Chart)
+
+	d.cmd = command(helmBin, args...)
+	d.cmd.Stdout(cfg.Stdout)
+	d.cmd.Stderr(cfg.Stderr)
+
+	if cfg.Debug {
+		fmt.Fprintf(cfg.Stderr, "Generated command: '%s'\n", d.cmd.String())
+	}
+
+	return nil
+}

internal/run/depupdate_test.go

@@ -0,0 +1,128 @@
+package run
+
+import (
+	"fmt"
+	"github.com/golang/mock/gomock"
+	"github.com/stretchr/testify/suite"
+	"strings"
+	"testing"
+)
+
+type DepUpdateTestSuite struct {
+	suite.Suite
+	ctrl            *gomock.Controller
+	mockCmd         *Mockcmd
+	originalCommand func(string, ...string) cmd
+}
+
+func (suite *DepUpdateTestSuite) BeforeTest(_, _ string) {
+	suite.ctrl = gomock.NewController(suite.T())
+	suite.mockCmd = NewMockcmd(suite.ctrl)
+
+	suite.originalCommand = command
+	command = func(path string, args ...string) cmd { return suite.mockCmd }
+}
+
+func (suite *DepUpdateTestSuite) AfterTest(_, _ string) {
+	command = suite.originalCommand
+}
+
+func TestDepUpdateTestSuite(t *testing.T) {
+	suite.Run(t, new(DepUpdateTestSuite))
+}
+
+func (suite *DepUpdateTestSuite) TestPrepareAndExecute() {
+	defer suite.ctrl.Finish()
+
+	stdout := strings.Builder{}
+	stderr := strings.Builder{}
+	cfg := Config{
+		Stdout: &stdout,
+		Stderr: &stderr,
+	}
+
+	command = func(path string, args ...string) cmd {
+		suite.Equal(helmBin, path)
+		suite.Equal([]string{"dependency", "update", "your_top_songs_2019"}, args)
+
+		return suite.mockCmd
+	}
+	suite.mockCmd.EXPECT().
+		Stdout(&stdout)
+	suite.mockCmd.EXPECT().
+		Stderr(&stderr)
+	suite.mockCmd.EXPECT().
+		Run().
+		Times(1)
+
+	d := DepUpdate{
+		Chart: "your_top_songs_2019",
+	}
+
+	suite.Require().NoError(d.Prepare(cfg))
+	suite.NoError(d.Execute(cfg))
+}
+
+func (suite *DepUpdateTestSuite) TestPrepareNamespaceFlag() {
+	defer suite.ctrl.Finish()
+
+	cfg := Config{
+		Namespace: "spotify",
+	}
+
+	command = func(path string, args ...string) cmd {
+		suite.Equal([]string{"--namespace", "spotify", "dependency", "update", "your_top_songs_2019"}, args)
+
+		return suite.mockCmd
+	}
+	suite.mockCmd.EXPECT().Stdout(gomock.Any()).AnyTimes()
+	suite.mockCmd.EXPECT().Stderr(gomock.Any()).AnyTimes()
+
+	d := DepUpdate{
+		Chart: "your_top_songs_2019",
+	}
+
+	suite.Require().NoError(d.Prepare(cfg))
+}
+
+func (suite *DepUpdateTestSuite) TestPrepareDebugFlag() {
+	defer suite.ctrl.Finish()
+
+	stdout := strings.Builder{}
+	stderr := strings.Builder{}
+	cfg := Config{
+		Debug:  true,
+		Stdout: &stdout,
+		Stderr: &stderr,
+	}
+
+	command = func(path string, args ...string) cmd {
+		suite.mockCmd.EXPECT().
+			String().
+			Return(fmt.Sprintf("%s %s", path, strings.Join(args, " ")))
+
+		return suite.mockCmd
+	}
+	suite.mockCmd.EXPECT().Stdout(gomock.Any()).AnyTimes()
+	suite.mockCmd.EXPECT().Stderr(gomock.Any()).AnyTimes()
+
+	d := DepUpdate{
+		Chart: "your_top_songs_2019",
+	}
+
+	suite.Require().NoError(d.Prepare(cfg))
+
+	want := fmt.Sprintf("Generated command: '%s --debug dependency update your_top_songs_2019'\n", helmBin)
+	suite.Equal(want, stderr.String())
+	suite.Equal("", stdout.String())
+}
+
+func (suite *DepUpdateTestSuite) TestPrepareChartRequired() {
+	d := DepUpdate{}
+
+	suite.mockCmd.EXPECT().Stdout(gomock.Any()).AnyTimes()
+	suite.mockCmd.EXPECT().Stderr(gomock.Any()).AnyTimes()
+
+	err := d.Prepare(Config{})
+	suite.EqualError(err, "chart is required")
+}