diff --git a/test/pisa/e2e/conftest.py b/test/pisa/e2e/conftest.py
index 72e6194..9585756 100644
--- a/test/pisa/e2e/conftest.py
+++ b/test/pisa/e2e/conftest.py
@@ -1,4 +1,5 @@
 import pytest
+import random
 from decimal import Decimal, getcontext
 
 import pisa.conf as conf
@@ -16,6 +17,17 @@ def bitcoin_cli():
     )
 
 
+@pytest.fixture(scope="session", autouse=True)
+def prng_seed():
+    random.seed(0)
+
+
+def get_random_value_hex(nbytes):
+    pseudo_random_value = random.getrandbits(8 * nbytes)
+    prv_hex = "{:x}".format(pseudo_random_value)
+    return prv_hex.zfill(2 * nbytes)
+
+
 @pytest.fixture()
 def create_txs(bitcoin_cli):
     set_up_node(bitcoin_cli)
@@ -24,8 +36,12 @@ def create_txs(bitcoin_cli):
     if len(utxos) == 0:
         raise ValueError("There're no UTXOs.")
 
-    commitment_tx_ins = {"txid": utxos[0].get("txid"), "vout": utxos[0].get("vout")}
-    commitment_tx_outs = {utxos[0].get("address"): utxos[0].get("amount") - Decimal(1 / pow(10, 5))}
+    utxo = utxos.pop(0)
+    while utxo.get("amount") < Decimal(2 / pow(10, 5)):
+        utxo = utxos.pop(0)
+
+    commitment_tx_ins = {"txid": utxo.get("txid"), "vout": utxo.get("vout")}
+    commitment_tx_outs = {utxo.get("address"): utxo.get("amount") - Decimal(1 / pow(10, 5))}
 
     raw_commitment_tx = bitcoin_cli.createrawtransaction([commitment_tx_ins], commitment_tx_outs)
     signed_commitment_tx = bitcoin_cli.signrawtransactionwithwallet(raw_commitment_tx)
@@ -61,8 +77,7 @@ def set_up_node(bitcoin_cli):
     bitcoin_cli.generatetoaddress(101, new_addr)
 
 
-def build_appointment_data(bitcoin_cli, commitment_tx, penalty_tx):
-    commitment_tx_id = bitcoin_cli.decoderawtransaction(commitment_tx).get("txid")
+def build_appointment_data(bitcoin_cli, commitment_tx_id, penalty_tx):
     current_height = bitcoin_cli.getblockcount()
 
     appointment_data = {