Test that the shipped data loads from a Go package per module, that a bare New fails naming WithDataFS, and that a read nothing provides names the modules its reader's manifest reads

data/misc/fs_test.go

@@ -0,0 +1,22 @@
+package misc_test
+
+import (
+	"io/fs"
+	"testing"
+
+	"github.com/larvit/fejkdata"
+	"github.com/larvit/fejkdata/data/misc"
+)
+
+func TestFSLoadsByItsManifest(t *testing.T) {
+	if _, err := fs.Stat(misc.FS, ".fejkdata.json"); err != nil {
+		t.Fatalf("FS holds no manifest: %v", err)
+	}
+	f, err := fejkdata.New(fejkdata.WithDataFS(misc.FS))
+	if err != nil {
+		t.Fatalf("New(WithDataFS(FS)) = %v", err)
+	}
+	if len(f.List()) == 0 {
+		t.Error("List() is empty, want the module's categories")
+	}
+}