refactor: improve anvil startup and teardown

test/programs/build_anvil_state.sh

@@ -9,8 +9,40 @@ rm -f $program_path/anvil_state.json
 anvil --disable-code-size-limit --preserve-historical-states --slots-in-an-epoch 1 \
     --dump-state $program_path/anvil_state.json > $program_path/_anvil.log 2>&1 &
 anvil_pid=$!
-sleep 5
-
+trap 'kill $anvil_pid' EXIT
+
+# wait for anvil to start listening
+num_tries=10
+while true
+do
+    if chain_id=$(cast chain-id 2>/dev/null)
+    then
+        if [[ $chain_id == 31337 ]]
+        then
+            >&2 echo "Anvil is listening."
+            break
+        else
+            >&2 echo "Anvil has unexpected chain ID $chain_id."
+            exit 1
+        fi
+    else
+        if kill -0 $anvil_pid
+        then
+            if [[ $num_tries == 0 ]]
+            then
+                >&2 echo "Anvil is not listening."
+                exit 1
+            else
+                >&2 echo "Waiting for Anvil to start listening... ($num_tries tries left)"
+                num_tries=$(( $num_tries - 1 ))
+                sleep 1
+            fi
+        else
+            >&2 echo "Anvil exited..."
+            exit 1
+        fi
+    fi
+done
 
 # deploy smart contracts
 initial_hash=`xxd -p -c32 "${program_path}/machine-image/hash"`
@@ -29,8 +61,3 @@ jq -r '.transactions[] | select(.transactionType=="CREATE") | select(.contractNa
     >> $program_path/addresses
 
 cast rpc anvil_mine 2
-
-#
-# kill anvil, thus dumping its state, to be loaded later by tests
-kill -INT "$anvil_pid"
-wait $anvil_pid