test generation in place

Author: phryneas

package-lock.json

@@ -48,6 +48,7 @@
   "devDependencies": {
     "@types/jscodeshift": "^17.3.0",
     "@types/node": "20.9.0",
+    "diff": "^8.0.2",
     "typescript": "^5.2.2",
     "vitest": "^1.0.1"
   }

scripts/codemods/ac3-to-ac4/package.json

@@ -0,0 +1,20 @@
+import { createPatch } from "diff";
+import type { Transform } from "jscodeshift";
+import { applyTransform } from "jscodeshift/dist/testUtils.js";
+
+export const createDiff = (transform: Transform) => (source: string) => {
+  const transformed = applyTransform(
+    transform,
+    {},
+    { source },
+    { parser: "ts" }
+  );
+  const patch = createPatch(
+    "test.ts",
+    source,
+    transformed || source,
+    "original",
+    "transformed"
+  );
+  return patch;
+};