diff --git a/test/src/BuildTest.ts b/test/src/BuildTest.ts
index a77b518f642..33ceace5c24 100644
--- a/test/src/BuildTest.ts
+++ b/test/src/BuildTest.ts
@@ -1,5 +1,5 @@
 import test from "./helpers/avaEx"
-import { assertPack } from "./helpers/packTester"
+import { assertPack, modifyPackageJson } from "./helpers/packTester"
 import { move, writeJson, readJson } from "fs-extra-p"
 import { Promise as BluebirdPromise } from "bluebird"
 import * as path from "path"
@@ -24,15 +24,13 @@ test("custom app dir", async () => {
   await assertPack("test-app-one", getPossiblePlatforms(), {
     // speed up tests, we don't need check every arch
     arch: process.arch
-  }, true, async (projectDir) => {
-    const file = path.join(projectDir, "package.json")
-    const data = await readJson(file)
-    data.directories = {
-      buildResources: "custom"
-    }
-
-    return await BluebirdPromise.all([
-      writeJson(file, data),
+  }, true, (projectDir) => {
+    return BluebirdPromise.all([
+      modifyPackageJson(projectDir, data => {
+        data.directories = {
+          buildResources: "custom"
+        }
+      }),
       move(path.join(projectDir, "build"), path.join(projectDir, "custom"))
     ])
   })
@@ -42,12 +40,10 @@ test("productName with space", async () => {
   await assertPack("test-app-one", getPossiblePlatforms(), {
     // speed up tests, we don't need check every arch
     arch: process.arch
-  }, true, async (projectDir) => {
-    const file = path.join(projectDir, "package.json")
-    const data = await readJson(file)
-    data.productName = "Test App"
-
-    return await writeJson(file, data)
+  }, true, (projectDir) => {
+    return modifyPackageJson(projectDir, data => {
+      data.productName = "Test App"
+    })
   })
 })
 
diff --git a/test/src/helpers/packTester.ts b/test/src/helpers/packTester.ts
index d9af7632f52..4c5467e668d 100644
--- a/test/src/helpers/packTester.ts
+++ b/test/src/helpers/packTester.ts
@@ -1,4 +1,4 @@
-import { copy, emptyDir, remove } from "fs-extra-p"
+import { copy, emptyDir, remove, writeJson, readJson } from "fs-extra-p"
 import * as assertThat from "should/as-function"
 import * as path from "path"
 import { parse as parsePlist } from "plist"
@@ -164,4 +164,11 @@ async function getContents(path: string, productName: string) {
     .map(it => it.length === 0 ? null : it.substring(it.indexOf(".") + 1))
     .filter(it => it != null && !(it.startsWith(`/opt/${productName}/locales/`) || it.startsWith(`/opt/${productName}/libgcrypt`)))
     )
+}
+
+export async function modifyPackageJson(projectDir: string, task: (data: any) => void): Promise<any> {
+  const file = path.join(projectDir, "package.json")
+  const data = await readJson(file)
+  task(data)
+  return await writeJson(file, data)
 }
\ No newline at end of file