Add some very basic tests

tests/operations/tests/RenderPDF.mjs

@@ -0,0 +1,37 @@
+/**
+ * RenderPDF tests.
+ *
+ * @copyright Crown Copyright 2026
+ * @license Apache-2.0
+ */
+import TestRegister from "../../lib/TestRegister.mjs";
+
+
+TestRegister.addTests([
+    {
+        name: "RenderPDF",
+        input: "Not a PDF",
+        expectedOutput: "Input does not appear to be a PDF file.",
+        recipeConfig: [
+            {
+                op: "Render PDF",
+                args: ["Raw"]
+            },
+        ],
+    },
+    {
+        name: "RenderPDF",
+        input: "",
+        expectedMatch: /^<iframe src="data:application\/pdf;base64,JVBERi0xLjAKCjEgMCBvYmogPDwg/,
+        recipeConfig: [
+            {
+                "op": "Generate QR Code",
+                "args": ["PDF", 1, 1, "Low"]
+            },
+            {
+                "op": "Render PDF",
+                "args": ["Raw"]
+            }
+        ],
+    },
+]);