diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index e91ff405c..3ad65ead5 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -267,6 +267,7 @@ jobs:
         uses: actions-rs/tarpaulin@v0.1
         with:
           out-type: Html
+          timeout: 600
 
       - name: Set branch name
         if: ${{ github.event_name == 'pull_request' }}
diff --git a/chain-impl-mockchain/src/certificate/test.rs b/chain-impl-mockchain/src/certificate/test.rs
index d541d8b90..5789eb12b 100644
--- a/chain-impl-mockchain/src/certificate/test.rs
+++ b/chain-impl-mockchain/src/certificate/test.rs
@@ -4,15 +4,20 @@ use crate::block::BlockDate;
 use crate::fragment::ConfigParams;
 use crate::ledger::governance::TreasuryGovernanceAction;
 use crate::rewards::TaxType;
+use crate::testing::data::CommitteeMembersManager;
 use crate::vote;
 #[cfg(test)]
 use chain_core::mempack::{ReadBuf, Readable};
 use chain_crypto::{testing, Ed25519};
 use chain_time::DurationSeconds;
+use chain_vote::{Crs, EncryptedTally};
 #[cfg(test)]
 use quickcheck::TestResult;
 use quickcheck::{Arbitrary, Gen};
 use quickcheck_macros::quickcheck;
+use rand::SeedableRng;
+use rand_chacha::ChaChaRng;
+use std::num::NonZeroU8;
 
 impl Arbitrary for PoolRetirement {
     fn arbitrary<G: Gen>(g: &mut G) -> Self {
@@ -191,8 +196,6 @@ impl Arbitrary for Proposals {
 
 impl Arbitrary for VotePlan {
     fn arbitrary<G: Gen>(g: &mut G) -> Self {
-        use rand_core::SeedableRng;
-
         let vote_start = BlockDate::arbitrary(g);
         let vote_end = BlockDate::arbitrary(g);
         let committee_end = BlockDate::arbitrary(g);
@@ -243,10 +246,53 @@ impl Arbitrary for VoteCast {
     }
 }
 
+fn arbitrary_decrypted_private_tally<G: Gen>(g: &mut G) -> DecryptedPrivateTally {
+    let proposals_n = u8::arbitrary(g);
+    let mut inner = Vec::new();
+    let mut rng = ChaChaRng::seed_from_u64(u64::arbitrary(g));
+    let crs_seed = String::arbitrary(g).into_bytes();
+    let committee_size = (g.next_u32() % 2 + 1) as usize; // very time consuming
+    let committee_manager =
+        CommitteeMembersManager::new(&mut rng, &crs_seed, committee_size, committee_size);
+
+    for _ in 0..proposals_n {
+        let n_options = NonZeroU8::arbitrary(g);
+
+        let encrypted_tally = EncryptedTally::new(
+            n_options.get() as usize,
+            committee_manager.election_pk(),
+            Crs::from_hash(&crs_seed),
+        );
+
+        let mut decrypte_shares = Vec::new();
+        for i in 0..committee_size {
+            decrypte_shares.push(
+                encrypted_tally
+                    .partial_decrypt(&mut rng, committee_manager.members()[i].secret_key()),
+            );
+        }
+
+        inner.push(DecryptedPrivateTallyProposal {
+            tally_result: (0..n_options.get())
+                .map(|_| u64::arbitrary(g))
+                .collect::<Box<[_]>>(),
+            decrypt_shares: decrypte_shares.into_boxed_slice(),
+        });
+    }
+    DecryptedPrivateTally::new(inner).unwrap()
+}
+
 impl Arbitrary for VoteTally {
     fn arbitrary<G: Gen>(g: &mut G) -> Self {
         let vote_plan_id = VotePlanId::arbitrary(g);
-        Self::new_public(vote_plan_id)
+
+        let private = bool::arbitrary(g);
+
+        if private {
+            Self::new_private(vote_plan_id, arbitrary_decrypted_private_tally(g))
+        } else {
+            Self::new_public(vote_plan_id)
+        }
     }
 }