test: add mmultiscripts preset only case

__test__/index.test.ts

@@ -935,5 +935,15 @@ describe('#convert', () => {
         expect(result).toBe('\\_{b}^{}X_{}^{c}');
       });
     });
+
+    describe('with preset only', () => {
+      it('add prescript and ignore subsup', () => {
+        const mathml = mathmlStrings.mmultiscriptPresetOnly;
+
+        const result = MathMLToLaTeX.convert(mathml);
+
+        expect(result).toBe('\\_{b}^{}X');
+      });
+    });
   });
 });

__test__/mocks/mathmlStrings.ts

@@ -1542,3 +1542,13 @@ export const mmultiscriptPresetWithNone = `<math xmlns="http://www.w3.org/1998/M
 
 </mmultiscripts>
 </math>`;
+
+export const mmultiscriptPresetOnly = `<math xmlns="http://www.w3.org/1998/Math/MathML" display="block">
+<mmultiscripts>
+  <mi>X</mi>      <!-- base expression -->
+  <mprescripts />
+  <mi>b</mi>      <!-- presubscript -->
+  <none />        <!-- presuperscript -->
+
+</mmultiscripts>
+</math>`;