backend: support external SPARQL and named-graph snapshots

backend_go/graph_snapshot_named_graph_test.go

@@ -0,0 +1,23 @@
+package main
+
+import (
+	"strings"
+	"testing"
+)
+
+func TestRDFSLabelQueryUsesNamedGraphs(t *testing.T) {
+	query := rdfsLabelQuery([]string{
+		"http://example.com/A",
+		"http://example.com/B",
+	})
+
+	if !strings.Contains(query, "SELECT DISTINCT ?s ?label") {
+		t.Fatalf("label query should de-duplicate rows across named graphs:\n%s", query)
+	}
+	if !strings.Contains(query, "GRAPH ?g") {
+		t.Fatalf("label query should read from named graphs:\n%s", query)
+	}
+	if !strings.Contains(query, "<"+rdfsLabelIRI+">") {
+		t.Fatalf("label query should still fetch rdfs:label:\n%s", query)
+	}
+}