validator tests: enable extension spec testing (#21685)

Extension spec tests were accidentally gated under a check for custom attrs, and
so weren't running.  Reenable them, after tweaking them so they're no longer
broken.

validator/engine/validator_test.js

@@ -1297,47 +1297,6 @@ describe('ValidatorRulesMakeSense', () => {
                   .toBe(true);
             });
       }
-      // TagSpecs with an ExtensionSpec are extensions. We have a few
-      // additional checks for these.
-      if (tagSpec.extensionSpec !== null) {
-        const {extensionSpec} = tagSpec;
-        it('extension must have a name field value', () => {
-          expect(extensionSpec.name).toBeDefined();
-        });
-        it('extension ' + extensionSpec.name + ' must have at least two ' +
-               'versions, latest and a numeric version, e.g `1.0`',
-        () => {
-          expect(extensionSpec.version).toBeGreaterThan(1);
-        });
-        it('extension ' + extensionSpec.name + ' versions must be `latest` ' +
-               'or a numeric value',
-        () => {
-          for (const versionString of extensionSpec.version) {
-            expect(versionString).toMatch(/^(latest|[0-9.])$/);
-          }
-          for (const versionString of extensionSpec.deprecatedVersion) {
-            expect(versionString).toMatch(/^(latest|[0-9.])$/);
-          }
-        });
-        it('extension ' + extensionSpec.name + ' deprecated_version must be ' +
-               'subset of version',
-        () => {
-          const versions = {};
-          for (const versionString of extensionSpec.version) {
-            expect(versionString).toMatch(/^(latest|[0-9.])$/);
-          }
-          for (const versionString of extensionSpec.deprecatedVersion) {
-            expect(versions.hasOwnProperty(versionString)).toBe(true);
-          }
-        });
-        it('extension ' + extensionSpec.name + ' must include the ' +
-               'attr_list: "common-extension-attrs"` attr_list ',
-        () => {
-          expect(tagSpec.attrLists.length).toEqual(1);
-          expect(tagSpec.attrLists[0]).toEqual('common-extension-attrs');
-        });
-      }
-
       if (attrSpec.dispatchKey) {
         it('tag_spec ' + tagSpecName +
            ' can not have more than one dispatch_key', () => {
@@ -1347,6 +1306,51 @@ describe('ValidatorRulesMakeSense', () => {
       }
     }
 
+    // TagSpecs with an ExtensionSpec are extensions. We have a few
+    // additional checks for these.
+    if (tagSpec.extensionSpec !== null) {
+      const {extensionSpec} = tagSpec;
+      const versionRegexp = /^(latest|[0-9]+[.][0-9]+)$/;
+      it('extension must have a name field value', () => {
+        expect(extensionSpec.name).toBeDefined();
+      });
+      it('extension ' + extensionSpec.name + ' must have at least two ' +
+             'versions, latest and a numeric version, e.g `1.0`',
+      () => {
+        expect(extensionSpec.version.length).toBeGreaterThan(1);
+      });
+      it('extension ' + extensionSpec.name + ' versions must be `latest` ' +
+             'or a numeric value',
+      () => {
+        for (const versionString of extensionSpec.version) {
+          expect(versionString).toMatch(versionRegexp);
+        }
+        for (const versionString of extensionSpec.deprecatedVersion) {
+          expect(versionString).toMatch(versionRegexp);
+        }
+      });
+      it('extension ' + extensionSpec.name + ' deprecated_version must be ' +
+             'subset of version',
+      () => {
+        for (const versionString of extensionSpec.deprecatedVersion) {
+          expect(extensionSpec.version).toContain(versionString);
+        }
+      });
+      it('extension ' + extensionSpec.name + ' must include the ' +
+             'attr_list: "common-extension-attrs"` attr_list ',
+      () => {
+        expect(tagSpec.attrLists.length).toEqual(1);
+        // TODO: what we'd like to verify here is that this AttrList is named
+        // 'common-extension-attrs'.  Unfortunately that information isn't
+        // available to us: we just have an index into
+        // Context.rules_.parsedAttrSpecs_.parsedAttrSpecs_.
+        // getNameByAttrSpecId() looks like it would do what we want, but it's
+        // sufficiently wrapped in private context inside the validator that I
+        // don't see a way to call it.  For now just gold the current index.
+        expect(tagSpec.attrLists[0]).toEqual(17);
+      });
+    }
+
     // cdata
     if (tagSpec.cdata !== null) {
       let usefulCdataSpec = false;