jsonschema: resolve URIs for $id

Assign a base URI to every schema.

See the comment on resolveURIs for details.

Change-Id: I2332d825c486766832503cabdd0bf9d819171d53
Reviewed-on: https://go-review.googlesource.com/c/tools/+/669997
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Alan Donovan <adonovan@google.com>

jsonschema/resolve_test.go

@@ -5,7 +5,10 @@
 package jsonschema
 
 import (
+	"maps"
+	"net/url"
 	"regexp"
+	"slices"
 	"testing"
 )
 
@@ -24,7 +27,7 @@ func TestCheckLocal(t *testing.T) {
 			"regexp",
 		},
 	} {
-		_, err := tt.s.Resolve()
+		_, err := tt.s.Resolve("")
 		if err == nil {
 			t.Errorf("%s: unexpectedly passed", tt.s.json())
 			continue
@@ -35,3 +38,56 @@ func TestCheckLocal(t *testing.T) {
 		}
 	}
 }
+
+func TestResolveURIs(t *testing.T) {
+	for _, baseURI := range []string{"", "http://a.com"} {
+		t.Run(baseURI, func(t *testing.T) {
+			root := &Schema{
+				ID: "http://b.com",
+				Items: &Schema{
+					ID: "/foo.json",
+				},
+				Contains: &Schema{
+					ID:     "/bar.json",
+					Anchor: "a",
+					Items: &Schema{
+						Anchor: "b",
+						Items: &Schema{
+							// An ID shouldn't be a query param, but this tests
+							// resolving an ID with its parent.
+							ID:     "?items",
+							Anchor: "c",
+						},
+					},
+				},
+			}
+			base, err := url.Parse(baseURI)
+			if err != nil {
+				t.Fatal(err)
+			}
+			got, err := resolveURIs(root, base)
+			if err != nil {
+				t.Fatal(err)
+			}
+
+			want := map[string]*Schema{
+				baseURI:                       root,
+				"http://b.com/foo.json":       root.Items,
+				"http://b.com/bar.json":       root.Contains,
+				"http://b.com/bar.json?items": root.Contains.Items.Items,
+			}
+			if baseURI != root.ID {
+				want[root.ID] = root
+			}
+
+			gotKeys := slices.Sorted(maps.Keys(got))
+			wantKeys := slices.Sorted(maps.Keys(want))
+			if !slices.Equal(gotKeys, wantKeys) {
+				t.Errorf("ID keys:\ngot  %q\nwant %q", gotKeys, wantKeys)
+			}
+			if !maps.Equal(got, want) {
+				t.Errorf("IDs:\ngot  %+v\n\nwant %+v", got, want)
+			}
+		})
+	}
+}