test: don't test if no markdown or ast

Author: agoose77

index.ts

@@ -359,12 +359,14 @@ files.forEach((file) => {
       if (html && !html.endsWith('\n')) {
         html = html.concat('\n');
       }
-      jsonTestCases = jsonTestCases.concat({
-        title: `${file.replace('.yml', '')}: ${testCase.title}`,
-        mdast: testCase.mdast,
-        myst: testCase.myst,
-        html,
-      });
+      if (testCase.myst !== undefined && testCase.mdast !== undefined) {
+        jsonTestCases.push({
+          title: `${file.replace('.yml', '')}: ${testCase.title}`,
+          mdast: testCase.mdast,
+          myst: testCase.myst,
+          html,
+        });
+      }
     }
     if (testCase.id) {
       const outFile = join(directory, `${testCase.id}.md`);