fix: finalize durable Pi lifecycle

tools/thothctl/internal/config/installation_test.go

@@ -51,6 +51,51 @@ func TestLoadSelectsServerComposeFiles(t *testing.T) {
 	assertStringsEqual(t, installation.ComposeFiles(), want)
 }
 
+func TestComposeArgsAutomaticallyIncludeTheInstallationCurrentImageOverride(t *testing.T) {
+	t.Parallel()
+
+	installationPath, _, _, _ := writeInstallation(t, "local")
+	seed, err := Load(installationPath)
+	if err != nil {
+		t.Fatal(err)
+	}
+	currentImage := seed.CurrentImageOverridePath()
+	if err := os.MkdirAll(filepath.Dir(currentImage), 0o700); err != nil {
+		t.Fatal(err)
+	}
+	if err := os.WriteFile(currentImage, []byte("services:\n  core:\n    image: candidate\n"), 0o600); err != nil {
+		t.Fatal(err)
+	}
+	installation, err := Load(installationPath)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	args := installation.ComposeArgs("up", "--detach")
+	want := []string{"-f", currentImage, "up", "--detach"}
+	if !containsSequence(args, want) {
+		t.Fatalf("ComposeArgs() = %#v, want durable override immediately before command", args)
+	}
+}
+
+func TestInstallationControlPathsAreIsolatedForDescriptorsSharingOneCheckout(t *testing.T) {
+	projectDirectory := t.TempDir()
+	first := Installation{Path: filepath.Join(t.TempDir(), installationFileName), ProjectDirectory: projectDirectory}
+	second := Installation{Path: filepath.Join(t.TempDir(), installationFileName), ProjectDirectory: projectDirectory}
+
+	if first.CurrentImageOverridePath() == second.CurrentImageOverridePath() {
+		t.Fatalf("shared-checkout installations reused %q", first.CurrentImageOverridePath())
+	}
+	for _, installation := range []Installation{first, second} {
+		if filepath.Dir(filepath.Dir(installation.CurrentImageOverridePath())) != filepath.Join(projectDirectory, ".thothctl") {
+			t.Fatalf("current-image path %q is not installation-specific under .thothctl", installation.CurrentImageOverridePath())
+		}
+		if filepath.Dir(installation.UpdateStatePath()) != filepath.Dir(installation.CurrentImageOverridePath()) {
+			t.Fatalf("state %q and selector %q do not share one installation control directory", installation.UpdateStatePath(), installation.CurrentImageOverridePath())
+		}
+	}
+}
+
 func TestLoadRejectsRelativeInstallationPaths(t *testing.T) {
 	t.Parallel()
 
@@ -100,3 +145,22 @@ func assertStringsEqual(t *testing.T, got, want []string) {
 		}
 	}
 }
+
+func containsSequence(values, wanted []string) bool {
+	for start := range values {
+		if len(values)-start < len(wanted) {
+			continue
+		}
+		matched := true
+		for offset := range wanted {
+			if values[start+offset] != wanted[offset] {
+				matched = false
+				break
+			}
+		}
+		if matched {
+			return true
+		}
+	}
+	return false
+}