diff --git a/src/converters/libheif.ts b/src/converters/libheif.ts
index 38ac949..b88e177 100644
--- a/src/converters/libheif.ts
+++ b/src/converters/libheif.ts
@@ -1,4 +1,5 @@
-import { execFile } from "child_process";
+import { execFile as execFileOriginal } from "child_process";
+import { ExecFileFn } from "./types.ts";
 
 export const properties = {
   from: {
@@ -14,8 +15,8 @@ export function convert(
   fileType: string,
   convertTo: string,
   targetPath: string,
-  // eslint-disable-next-line @typescript-eslint/no-unused-vars
   options?: unknown,
+  execFile: ExecFileFn = execFileOriginal, // to make it mockable
 ): Promise<string> {
   return new Promise((resolve, reject) => {
     execFile("heif-convert", [filePath, targetPath], (error, stdout, stderr) => {
diff --git a/tests/converters/libheif.test.ts b/tests/converters/libheif.test.ts
new file mode 100644
index 0000000..33625c5
--- /dev/null
+++ b/tests/converters/libheif.test.ts
@@ -0,0 +1,19 @@
+import { test } from "bun:test";
+import { convert } from "../../src/converters/libheif.ts";
+import {
+  runConvertFailTest,
+  runConvertLogsStderror,
+  runConvertSuccessTest,
+} from "./helpers/converters.ts";
+
+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);
+});