General source code refactoring

tests/consumptionTrend.test.cjs

@@ -1,21 +1,9 @@
 const assert = require("node:assert/strict");
-const fs = require("node:fs");
-const path = require("node:path");
 const vm = require("node:vm");
+const { loadApplication, composeScript } = require("./support/application.cjs");
 
-const root = path.resolve(__dirname, "..");
 
 function loadContentHelpers() {
-  const source = fs.readFileSync(path.join(root, "src", "content.js"), "utf8");
-  const marker = "\n  if (insertTile()) {";
-  const instrumented = source.replace(marker, `
-  globalThis.__consumptionTrendTest = {
-    normalizeConsumptionTrendItems,
-    formatConsumptionPointLabel,
-    createNiceConsumptionMaximum,
-    calculateAverageConsumption
-  };
-${marker}`);
   const context = {
     chrome: { runtime: { onMessage: { addListener() {} } } },
     document: { getElementById: () => ({}) },
@@ -36,13 +24,12 @@ ${marker}`);
     Math
   };
 
-  vm.runInNewContext(instrumented, context);
-  return context.__consumptionTrendTest;
+  return loadApplication("content", context).consumptionModel;
 }
 
 function loadBackground(fetchCalls) {
   let listener;
-  const source = fs.readFileSync(path.join(root, "src", "background.js"), "utf8");
+  const source = composeScript("background");
   const headers = {
     get(name) {
       return name.toLowerCase() === "content-type" ? "application/json" : null;