test(kiosk): manifest, identity, version and client unit tests

- TestReadIdentity: literal, const, chained, cross-package, alias,
  other-module and Requires shapes; refusals naming ID()/Requires()
- TestDerive, TestManifestFormat, TestCheck, TestVersions,
  TestRegistryClient (httptest: escaping, 404, envelopes, cap, redirect)
- runnable ExampleMarshal and ExampleNewestCompatible
- party TestDescribe: copy of the plugin list, publish once per app

modules/party/info_test.go

@@ -0,0 +1,61 @@
+package party
+
+import (
+	"strings"
+	"testing"
+
+	"git.golem15.com/golem15/summercms/modules/backpack"
+	"git.golem15.com/golem15/summercms/modules/compass"
+)
+
+// TestDescribe covers publishing the build-time plugin metadata.
+func TestDescribe(t *testing.T) {
+	if err := Describe(nil, nil, "v0.6.0"); err == nil || !strings.Contains(err.Error(), "app is nil") {
+		t.Errorf("Describe(nil) = %v", err)
+	}
+
+	app := backpack.New(&compass.Config{})
+	if _, ok := app.Lookup[Installed](); ok {
+		t.Fatal("a fresh app already has Installed")
+	}
+	plugins := []Info{
+		{ID: "acme.user", Module: "example.test/sm-user-plugin", Package: "example.test/sm-user-plugin", Name: "User", Version: "v0.1.2", Source: SourceModule},
+		{ID: "acme.shop", Package: "example.test/app/plugins/acme/shop", Source: SourceLocal},
+	}
+	if err := Describe(app, plugins, "v0.6.0"); err != nil {
+		t.Fatalf("Describe: %v", err)
+	}
+	// The caller's slice is copied: changing it later does not change
+	// what the app published.
+	plugins[0].Version = "v9.9.9"
+	got, ok := app.Lookup[Installed]()
+	if !ok {
+		t.Fatal("Installed not published")
+	}
+	if got.Framework != "v0.6.0" || len(got.Plugins) != 2 || got.Plugins[0].Version != "v0.1.2" || got.Plugins[1].Source != SourceLocal {
+		t.Errorf("Installed = %+v", got)
+	}
+
+	// Describe publishes once per app (the generated main calls it once,
+	// before Activate); a second call is refused and the first stays.
+	if err := Describe(app, nil, "v0.7.0"); err == nil || !strings.Contains(err.Error(), "party:") {
+		t.Errorf("second Describe = %v, want a duplicate error", err)
+	}
+	if again, _ := app.Lookup[Installed](); again.Framework != "v0.6.0" || len(again.Plugins) != 2 {
+		t.Errorf("after a second Describe: %+v", again)
+	}
+
+	empty := backpack.New(&compass.Config{})
+	if err := Describe(empty, nil, ""); err != nil {
+		t.Fatalf("Describe with no plugins: %v", err)
+	}
+	if got, ok := empty.Lookup[Installed](); !ok || got.Plugins == nil || len(got.Plugins) != 0 || got.Framework != "" {
+		t.Errorf("empty Installed = %+v, %v", got, ok)
+	}
+
+	for _, s := range []string{SourceModule, SourceSubmodule, SourceLocal} {
+		if s == "" || strings.ToLower(s) != s {
+			t.Errorf("source constant %q", s)
+		}
+	}
+}