diff --git a/test/integration/installExtension.test.ts b/test/integration/installExtension.test.ts
index d22cee802..ad4756f8a 100644
--- a/test/integration/installExtension.test.ts
+++ b/test/integration/installExtension.test.ts
@@ -22,4 +22,11 @@ describe("--install-extension", () => {
     const statInfo = await stat(pathToExtFolder)
     expect(statInfo.isDirectory()).toBe(true)
   }, 20000)
+  it("should use EXTENSIONS_GALLERY when set", async () => {
+    const extName = `author.extension-1.0.0`
+    const { stderr } = await runCodeServerCommand([...setupFlags, "--install-extension", extName], {
+      EXTENSIONS_GALLERY: "{}",
+    })
+    expect(stderr).toMatch("No extension gallery service configured")
+  })
 })
diff --git a/test/utils/runCodeServerCommand.ts b/test/utils/runCodeServerCommand.ts
index cb1e45638..bd526e85a 100644
--- a/test/utils/runCodeServerCommand.ts
+++ b/test/utils/runCodeServerCommand.ts
@@ -6,9 +6,14 @@ import { promisify } from "util"
  *
  * A helper function for integration tests to run code-server commands.
  */
-export async function runCodeServerCommand(argv: string[]): Promise<{ stdout: string; stderr: string }> {
+export async function runCodeServerCommand(
+  argv: string[],
+  env?: NodeJS.ProcessEnv,
+): Promise<{ stdout: string; stderr: string }> {
   const CODE_SERVER_COMMAND = process.env.CODE_SERVER_PATH || path.resolve("../../release-standalone/bin/code-server")
-  const { stdout, stderr } = await promisify(exec)(`${CODE_SERVER_COMMAND} ${argv.join(" ")}`)
+  const { stdout, stderr } = await promisify(exec)(`${CODE_SERVER_COMMAND} ${argv.join(" ")}`, {
+    env: { ...process.env, ...env },
+  })
 
   return { stdout, stderr }
 }