Added test case for axios.interceptors.response with missing alert.

javascript/ql/test/query-tests/Security/CWE-079/DomBasedXss/interceptors.js

@@ -0,0 +1,20 @@
+const express = require("express");
+const axios = require("axios");
+
+const app = express();
+
+axios.interceptors.response.use(
+    (response) => { // $ MISSING: Source
+        const userGeneratedHtml = response.data;
+        document.getElementById("content").innerHTML = userGeneratedHtml; // $ MISSING: Alert
+        return response;
+    },
+    (error) => {
+        return Promise.reject(error);
+    }
+);
+
+app.post("/fetch", (req, res) => {
+    const { url } = req.body;
+    axios.get(url);
+});