Fix tests certificate chain

Giving a higher probability to win lotteries to the signer fixes the problem.
Just modifying the value of the party_id created the same problem in the main branch (with the same stake distribution).

Author: jpraynaud

mithril-aggregator/tests/certificate_chain.rs

@@ -13,7 +13,7 @@ async fn certificate_chain() {
     let protocol_parameters = ProtocolParameters {
         k: 5,
         m: 100,
-        phi_f: 0.65,
+        phi_f: 0.95,
     };
     let mut tester = RuntimeTester::build(protocol_parameters.clone()).await;
 

mithril-aggregator/tests/create_certificate.rs

@@ -10,7 +10,7 @@ async fn create_certificate() {
     let protocol_parameters = ProtocolParameters {
         k: 5,
         m: 100,
-        phi_f: 0.65,
+        phi_f: 0.95,
     };
     let mut tester = RuntimeTester::build(protocol_parameters.clone()).await;
 

mithril-aggregator/tests/test_extensions/runtime_tester.rs

@@ -221,6 +221,13 @@ impl RuntimeTester {
                             e
                         )
                     })?;
+            } else {
+                panic!(
+                    "Signer '{}' could not sign. \
+                    This test is based on the assumption that every signer signs everytime. \
+                    Possible fix: relax the protocol parameters or give more stakes to this signer.",
+                    signer_with_stake.party_id
+                );
             }
         }