Governance: Add test for removing signatory after signing (#2178)

governance/program/tests/process_remove_signatory.rs

@@ -213,3 +213,53 @@ async fn test_remove_signatory_with_not_editable_error() {
         GovernanceError::InvalidStateCannotEditSignatories.into()
     );
 }
+
+#[tokio::test]
+async fn test_remove_signatory_with_already_signed_error() {
+    // Arrange
+    let mut governance_test = GovernanceProgramTest::start_new().await;
+
+    let realm_cookie = governance_test.with_realm().await;
+    let governed_account_cookie = governance_test.with_governed_account().await;
+
+    let mut account_governance_cookie = governance_test
+        .with_account_governance(&realm_cookie, &governed_account_cookie)
+        .await
+        .unwrap();
+
+    let token_owner_record_cookie = governance_test
+        .with_community_token_deposit(&realm_cookie)
+        .await;
+
+    let proposal_cookie = governance_test
+        .with_proposal(&token_owner_record_cookie, &mut account_governance_cookie)
+        .await
+        .unwrap();
+
+    let signatory_record_cookie = governance_test
+        .with_signatory(&proposal_cookie, &token_owner_record_cookie)
+        .await
+        .unwrap();
+
+    governance_test
+        .sign_off_proposal(&proposal_cookie, &signatory_record_cookie)
+        .await
+        .unwrap();
+
+    // Act
+    let err = governance_test
+        .remove_signatory(
+            &proposal_cookie,
+            &token_owner_record_cookie,
+            &signatory_record_cookie,
+        )
+        .await
+        .err()
+        .unwrap();
+
+    // Assert
+    assert_eq!(
+        err,
+        GovernanceError::InvalidStateCannotEditSignatories.into()
+    );
+}