screens: the console as spin c2f060202 draws it - no findings

cmd/screens/main.go

@@ -120,8 +120,9 @@ func run() error {
 		return err
 	}
 	// One file a screen: a test that is retried starts a new worker, which would lose what an
-	// earlier test had gathered in memory.
-	var a audit
+	// earlier test had gathered in memory. An audit with nothing found is an empty list, not null:
+	// screens.html reads it as an array.
+	a := audit{Findings: []finding{}}
 	audits, err := filepath.Glob(filepath.Join(*from, "*.audit.json"))
 	if err != nil {
 		return err
@@ -212,6 +213,9 @@ func whole(screens []screen, images []string, a audit) error {
 			errs = append(errs, fmt.Errorf("%s was not taken", w))
 		}
 	}
+	if a.Findings == nil {
+		errs = append(errs, errors.New("the audit's findings are null, not a list: screens.html reads an array"))
+	}
 	for _, f := range a.Findings {
 		if !names[f.Screen] || !slices.Contains(themes, f.Theme) || !slices.Contains(widths, f.Width) {
 			errs = append(errs, fmt.Errorf("a finding about %s.%s.%s, which the catalog does not have", f.Screen, f.Theme, f.Width))

cmd/screens/main_test.go

@@ -16,13 +16,18 @@ func TestWholeRefusesACatalogWithAGap(t *testing.T) {
 		screens []screen
 		images  []string
 		audit   audit
+		null    bool
 		refused string
 	}{
 		{name: "every theme at every width", screens: []screen{workspaces}, images: all},
 		{name: "a width not taken", screens: []screen{workspaces}, images: all[1:], refused: "workspaces.dark.desktop.png was not taken"},
 		{name: "an image of no screen", screens: []screen{workspaces}, images: append(all, "gone.light.desktop.png"), refused: "gone.light.desktop.png is no screen"},
 		{name: "a kind that is neither", screens: []screen{{Name: "workspaces", Kind: "drawer"}}, images: all, refused: `"drawer", not a page or a dialog`},
 		{name: "one name twice", screens: []screen{workspaces, workspaces}, images: all, refused: "two screens are named workspaces"},
+		{
+			name: "findings that are null", screens: []screen{workspaces}, images: all, null: true,
+			refused: "the audit's findings are null",
+		},
 		{
 			name: "a finding about no screen", screens: []screen{workspaces}, images: all,
 			audit:   audit{Findings: []finding{{Screen: "gone", Theme: "dark", Width: "desktop"}}},
@@ -36,6 +41,9 @@ func TestWholeRefusesACatalogWithAGap(t *testing.T) {
 	}
 	for _, c := range cases {
 		t.Run(c.name, func(t *testing.T) {
+			if c.audit.Findings == nil && !c.null {
+				c.audit.Findings = []finding{}
+			}
 			err := whole(c.screens, c.images, c.audit)
 			if c.refused == "" {
 				if err != nil {