diff --git a/src/converters/vips.ts b/src/converters/vips.ts
index 6451cda..b89db12 100644
--- a/src/converters/vips.ts
+++ b/src/converters/vips.ts
@@ -1,4 +1,5 @@
-import { execFile } from "node:child_process";
+import { execFile as execFileOriginal } from "node:child_process";
+import { ExecFileFn } from "./types.ts";
 
 // declare possible conversions
 export const properties = {
@@ -94,8 +95,8 @@ export function convert(
   fileType: string,
   convertTo: string,
   targetPath: string,
-  // eslint-disable-next-line @typescript-eslint/no-unused-vars
   options?: unknown,
+  execFile: ExecFileFn = execFileOriginal,
 ): Promise<string> {
   // if (fileType === "svg") {
   //   const scale = options.scale || 1;
diff --git a/tests/converters/vips.test.ts b/tests/converters/vips.test.ts
new file mode 100644
index 0000000..dec12dd
--- /dev/null
+++ b/tests/converters/vips.test.ts
@@ -0,0 +1,79 @@
+import type { ExecFileException } from "node:child_process";
+import { beforeEach, expect, test } from "bun:test";
+import { ExecFileFn } from "../../src/converters/types.ts";
+import { convert } from "../../src/converters/vips.ts";
+import {
+  runConvertFailTest,
+  runConvertLogsStderror,
+  runConvertSuccessTest,
+} from "./helpers/converters.ts";
+
+let calls: string[][] = [];
+
+beforeEach(() => {
+  calls = [];
+});
+
+test("convert resolves when execFile succeeds", async () => {
+  await runConvertSuccessTest(convert);
+});
+
+test("convert rejects when execFile fails", async () => {
+  await runConvertFailTest(convert);
+});
+
+test("convert logs stderr when present", async () => {
+  await runConvertLogsStderror(convert);
+});
+
+test("convert uses action pdfload with filetype being pdf", async () => {
+  const originalConsoleLog = console.log;
+
+  let loggedMessage = "";
+  console.log = (msg) => {
+    loggedMessage = msg;
+  };
+
+  const mockExecFile: ExecFileFn = (
+    _cmd: string,
+    _args: string[],
+    callback: (err: ExecFileException | null, stdout: string, stderr: string) => void,
+  ) => {
+    calls.push(_args);
+    callback(null, "Fake stdout", "");
+  };
+
+  const result = await convert("input.pdf", "pdf", "obj", "output.obj", undefined, mockExecFile);
+
+  console.log = originalConsoleLog;
+
+  expect(result).toBe("Done");
+  expect(calls[0]).toEqual(expect.arrayContaining(["pdfload"]));
+  expect(loggedMessage).toBe("stdout: Fake stdout");
+});
+
+test("convert uses action copy with filetype being anything but pdf", async () => {
+  const originalConsoleLog = console.log;
+
+  let loggedMessage = "";
+  console.log = (msg) => {
+    loggedMessage = msg;
+  };
+
+  const mockExecFile: ExecFileFn = (
+    _cmd: string,
+    _args: string[],
+    callback: (err: ExecFileException | null, stdout: string, stderr: string) => void,
+  ) => {
+    calls.push(_args);
+    callback(null, "Fake stdout", "");
+  };
+
+  const result = await convert("input.jpg", "jpg", "obj", "output.obj", undefined, mockExecFile);
+
+  console.log = originalConsoleLog;
+
+  expect(result).toBe("Done");
+  expect(calls[0]).toEqual(expect.arrayContaining(["copy"]));
+  expect(loggedMessage).toBe("stdout: Fake stdout");
+});