fix: Fix needs to work for upgrades and when selectors are provided (#922)

* fix: Fix `needs` to work for upgrades and when selectors are provided

Fixes #919

* Add test framework for `helmfile apply`

* Various enhancements and fixes to the DAG support

- Make the order of upgrades/deletes more deterministic for testability
- Fix the test framework so that we can validate log outputs and errors
- Add more test cases for `helmfile apply`, along with bug fixes.
- Make sure it fails with an intuitive error when you have non-existent releases referenced from witin "needs"

pkg/exectest/helm.go

@@ -0,0 +1,167 @@
+package exectest
+
+import (
+	"errors"
+	"fmt"
+	"strings"
+	"sync"
+
+	"github.com/roboll/helmfile/pkg/helmexec"
+)
+
+type ListKey struct {
+	Filter string
+	Flags  string
+}
+
+type DiffKey struct {
+	Name  string
+	Chart string
+	Flags string
+}
+
+type Helm struct {
+	Charts               []string
+	Repo                 []string
+	Releases             []Release
+	Deleted              []Release
+	Lists                map[ListKey]string
+	Diffs                map[DiffKey]error
+	Diffed               []Release
+	FailOnUnexpectedDiff bool
+	FailOnUnexpectedList bool
+
+	UpdateDepsCallbacks map[string]func(string) error
+
+	DiffMutex     *sync.Mutex
+	ChartsMutex   *sync.Mutex
+	ReleasesMutex *sync.Mutex
+}
+
+type Release struct {
+	Name  string
+	Flags []string
+}
+
+type Affected struct {
+	Upgraded []*Release
+	Deleted  []*Release
+	Failed   []*Release
+}
+
+func (helm *Helm) UpdateDeps(chart string) error {
+	if strings.Contains(chart, "error") {
+		return fmt.Errorf("simulated UpdateDeps failure for chart: %s", chart)
+	}
+	helm.Charts = append(helm.Charts, chart)
+
+	if helm.UpdateDepsCallbacks != nil {
+		callback, exists := helm.UpdateDepsCallbacks[chart]
+		if exists {
+			if err := callback(chart); err != nil {
+				return err
+			}
+		}
+	}
+	return nil
+}
+
+func (helm *Helm) BuildDeps(name, chart string) error {
+	if strings.Contains(chart, "error") {
+		return errors.New("error")
+	}
+	helm.Charts = append(helm.Charts, chart)
+	return nil
+}
+
+func (helm *Helm) SetExtraArgs(args ...string) {
+	return
+}
+func (helm *Helm) SetHelmBinary(bin string) {
+	return
+}
+func (helm *Helm) AddRepo(name, repository, cafile, certfile, keyfile, username, password string) error {
+	helm.Repo = []string{name, repository, cafile, certfile, keyfile, username, password}
+	return nil
+}
+func (helm *Helm) UpdateRepo() error {
+	return nil
+}
+func (helm *Helm) SyncRelease(context helmexec.HelmContext, name, chart string, flags ...string) error {
+	if strings.Contains(name, "error") {
+		return errors.New("error")
+	}
+	helm.sync(helm.ReleasesMutex, func() {
+		helm.Releases = append(helm.Releases, Release{Name: name, Flags: flags})
+	})
+	helm.sync(helm.ChartsMutex, func() {
+		helm.Charts = append(helm.Charts, chart)
+	})
+
+	return nil
+}
+func (helm *Helm) DiffRelease(context helmexec.HelmContext, name, chart string, flags ...string) error {
+	if helm.DiffMutex != nil {
+		helm.DiffMutex.Lock()
+	}
+	helm.Diffed = append(helm.Diffed, Release{Name: name, Flags: flags})
+	if helm.DiffMutex != nil {
+		helm.DiffMutex.Unlock()
+	}
+	key := DiffKey{Name: name, Chart: chart, Flags: strings.Join(flags, "")}
+	err, ok := helm.Diffs[key]
+	if !ok && helm.FailOnUnexpectedDiff {
+		return fmt.Errorf("unexpected diff with key: %v", key)
+	}
+	return err
+}
+func (helm *Helm) ReleaseStatus(context helmexec.HelmContext, release string, flags ...string) error {
+	if strings.Contains(release, "error") {
+		return errors.New("error")
+	}
+	helm.Releases = append(helm.Releases, Release{Name: release, Flags: flags})
+	return nil
+}
+func (helm *Helm) DeleteRelease(context helmexec.HelmContext, name string, flags ...string) error {
+	if strings.Contains(name, "error") {
+		return errors.New("error")
+	}
+	helm.Deleted = append(helm.Deleted, Release{Name: name, Flags: flags})
+	return nil
+}
+func (helm *Helm) List(context helmexec.HelmContext, filter string, flags ...string) (string, error) {
+	key := ListKey{Filter: filter, Flags: strings.Join(flags, "")}
+	res, ok := helm.Lists[key]
+	if !ok && helm.FailOnUnexpectedList {
+		return "", fmt.Errorf("unexpected list key: %v", key)
+	}
+	return res, nil
+}
+func (helm *Helm) DecryptSecret(context helmexec.HelmContext, name string, flags ...string) (string, error) {
+	return "", nil
+}
+func (helm *Helm) TestRelease(context helmexec.HelmContext, name string, flags ...string) error {
+	if strings.Contains(name, "error") {
+		return errors.New("error")
+	}
+	helm.Releases = append(helm.Releases, Release{Name: name, Flags: flags})
+	return nil
+}
+func (helm *Helm) Fetch(chart string, flags ...string) error {
+	return nil
+}
+func (helm *Helm) Lint(name, chart string, flags ...string) error {
+	return nil
+}
+func (helm *Helm) TemplateRelease(name, chart string, flags ...string) error {
+	return nil
+}
+
+func (helm *Helm) sync(m *sync.Mutex, f func()) {
+	if m != nil {
+		m.Lock()
+		defer m.Unlock()
+	}
+
+	f()
+}