diff --git a/dist/main.cjs b/dist/main.cjs
index de54429..a6cdabe 100644
--- a/dist/main.cjs
+++ b/dist/main.cjs
@@ -23375,9 +23375,7 @@ async function run() {
 }
 var main_default = run().catch((error2) => {
   console.error(error2);
-  if (process.env.GITHUB_OUTPUT !== void 0) {
-    setFailed(error2.message);
-  }
+  setFailed(error2.message);
 });
 /*! Bundled license information:
 
diff --git a/main.js b/main.js
index ec65c02..47af2fe 100644
--- a/main.js
+++ b/main.js
@@ -48,10 +48,7 @@ async function run() {
 
 // Export promise for testing
 export default run().catch((error) => {
-  /* c8 ignore next 5 */
+  /* c8 ignore next 3 */
   console.error(error);
-  // Don't set failed in test mode (when GITHUB_OUTPUT is undefined)
-  if (process.env.GITHUB_OUTPUT !== undefined) {
-    core.setFailed(error.message);
-  }
+  core.setFailed(error.message);
 });
diff --git a/tests/index.js b/tests/index.js
index 11ce4a8..74cf272 100644
--- a/tests/index.js
+++ b/tests/index.js
@@ -46,9 +46,18 @@ for (const file of testFiles) {
       NODE_USE_ENV_PROXY,
       ...env
     } = process.env;
-    const { stderr, stdout } = await execFileAsync("node", [`tests/${file}`], {
-      env,
-    });
+    let stderr, stdout;
+    try {
+      ({ stderr, stdout } = await execFileAsync("node", [`tests/${file}`], {
+        env,
+      }));
+    } catch (error) {
+      if (!(error instanceof Error) || !("stderr" in error) || !("stdout" in error)) {
+        throw error;
+      }
+
+      ({ stderr, stdout } = error);
+    }
     const trimmedStderr = normalizeStderr(stderr).replace(/\r?\n$/, "");
     const trimmedStdout = stdout.replace(/\r?\n$/, "");
     await t.test("stderr", (t) => {
diff --git a/tests/index.js.snapshot b/tests/index.js.snapshot
index ba868b6..2b250a8 100644
--- a/tests/index.js.snapshot
+++ b/tests/index.js.snapshot
@@ -30,6 +30,7 @@ Error: No enterprise installation found matching the name test-enterprise.
 exports[`main-enterprise-installation-not-found.test.js > stdout 1`] = `
 Creating enterprise installation token for enterprise "test-enterprise".
 Failed to create token for enterprise "test-enterprise" (attempt 1): No enterprise installation found matching the name test-enterprise.
+::error::No enterprise installation found matching the name test-enterprise.
 --- REQUESTS ---
 GET /enterprises/test-enterprise/installation
 `;
@@ -44,6 +45,10 @@ Error: Cannot use 'enterprise' input with 'owner' or 'repositories' inputs
     at async file://<cwd>/tests/main-enterprise-mutual-exclusivity-owner.test.js:<line>:<column>
 `;
 
+exports[`main-enterprise-mutual-exclusivity-owner.test.js > stdout 1`] = `
+::error::Cannot use 'enterprise' input with 'owner' or 'repositories' inputs
+`;
+
 exports[`main-enterprise-mutual-exclusivity-repositories.test.js > stderr 1`] = `
 Error: Cannot use 'enterprise' input with 'owner' or 'repositories' inputs
     at main (file://<cwd>/lib/main.js:<line>:<column>)
@@ -54,6 +59,10 @@ Error: Cannot use 'enterprise' input with 'owner' or 'repositories' inputs
     at async file://<cwd>/tests/main-enterprise-mutual-exclusivity-repositories.test.js:<line>:<column>
 `;
 
+exports[`main-enterprise-mutual-exclusivity-repositories.test.js > stdout 1`] = `
+::error::Cannot use 'enterprise' input with 'owner' or 'repositories' inputs
+`;
+
 exports[`main-enterprise-only-success.test.js > stdout 1`] = `
 Creating enterprise installation token for enterprise "test-enterprise".
 ::add-mask::ghs_16C7e42F292c6912E7710c838347Ae178B4a
@@ -117,6 +126,10 @@ exports[`main-proxy-requires-native-support.test.js > stderr 1`] = `
 A proxy environment variable is set, but Node.js native proxy support is not enabled. Set NODE_USE_ENV_PROXY=1 for this action step.
 `;
 
+exports[`main-proxy-requires-native-support.test.js > stdout 1`] = `
+::error::A proxy environment variable is set, but Node.js native proxy support is not enabled. Set NODE_USE_ENV_PROXY=1 for this action step.
+`;
+
 exports[`main-repo-skew.test.js > stderr 1`] = `
 'Issued at' claim ('iat') must be an Integer representing the time that the assertion was issued.
 [@octokit/auth-app] GitHub API time and system time are different by 30 seconds. Retrying request with the difference accounted for.