diff --git a/dist/index.js b/dist/index.js
index 3687bbd..cdd6319 100644
--- a/dist/index.js
+++ b/dist/index.js
@@ -323,6 +323,10 @@ class TestReporter {
             core.setFailed(`Input parameter 'list-tests' has invalid value`);
             return;
         }
+        if (this.collapsed !== 'auto' && this.collapsed !== 'always' && this.collapsed !== 'never') {
+            core.setFailed(`Input parameter 'collapsed' has invalid value`);
+            return;
+        }
         if (isNaN(this.maxAnnotations) || this.maxAnnotations < 0 || this.maxAnnotations > 50) {
             core.setFailed(`Input parameter 'max-annotations' has invalid value`);
             return;
diff --git a/src/main.ts b/src/main.ts
index 1dccea7..218377f 100644
--- a/src/main.ts
+++ b/src/main.ts
@@ -67,6 +67,11 @@ class TestReporter {
       return
     }
 
+    if (this.collapsed !== 'auto' && this.collapsed !== 'always' && this.collapsed !== 'never') {
+      core.setFailed(`Input parameter 'collapsed' has invalid value`)
+      return
+    }
+
     if (isNaN(this.maxAnnotations) || this.maxAnnotations < 0 || this.maxAnnotations > 50) {
       core.setFailed(`Input parameter 'max-annotations' has invalid value`)
       return