diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 4b67c5e..d94cd5c 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -8,6 +8,8 @@ jobs:
     steps:
       - name: Checkout
         uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
       - name: Set up Python 3.10
         uses: actions/setup-python@v4
         with:
diff --git a/app/test_calculator.py b/app/test_calculator.py
index f564193..27345dc 100644
--- a/app/test_calculator.py
+++ b/app/test_calculator.py
@@ -1,8 +1,13 @@
+import random
+
 from .calculator import Calculator
 
 
+def test_fail():
+    assert True == False
+
 def test_add():
-    assert Calculator.add(1, 2) == 3.0
+    # assert Calculator.add(1, 2) == 3.0
     assert Calculator.add(1.0, 2.0) == 3.0
     assert Calculator.add(0, 2.0) == 2.0
     assert Calculator.add(2.0, 0) == 2.0
@@ -24,6 +29,8 @@ def test_multiply():
     assert Calculator.multiply(-4, 2.0) == -8.0
 
 def test_divide():
+    if random.random() < 0.2:
+        assert True == False
     # assert Calculator.divide(1, 2) == 0.5
     assert Calculator.divide(1.0, 2.0) == 0.5
     assert Calculator.divide(0, 2.0) == 0