diff --git a/bad_code.py b/bad_code.py
new file mode 100644
index 0000000..28c5854
--- /dev/null
+++ b/bad_code.py
@@ -0,0 +1,10 @@
+def poorly_formatted(x, y):
+    if x > y:
+        return x
+    else:
+        return y
+
+
+def another_function(a, b):
+    result = a + b
+    return result
diff --git a/calculator.py b/calculator.py
new file mode 100644
index 0000000..2db6275
--- /dev/null
+++ b/calculator.py
@@ -0,0 +1,13 @@
+def add(a, b):
+    """Add two numbers together."""
+    return a + b
+
+def multiply(a, b):
+    """Multiply two numbers."""
+    return a * b
+
+def divide(a, b):
+    """Divide two numbers."""
+    if b == 0:
+        raise ValueError("Cannot divide by zero")
+    return a / b
diff --git a/tests/test_bad_code.py b/tests/test_bad_code.py
new file mode 100644
index 0000000..4e8f5a6
--- /dev/null
+++ b/tests/test_bad_code.py
@@ -0,0 +1,5 @@
+from bad_code import poorly_formatted
+
+def test_poorly_formatted():
+    # Fixed test - should pass now
+    assert poorly_formatted(5, 3) == 5  # Correct!
diff --git a/tests/test_calculator.py b/tests/test_calculator.py
new file mode 100644
index 0000000..5e39b62
--- /dev/null
+++ b/tests/test_calculator.py
@@ -0,0 +1,15 @@
+import pytest
+from calculator import add, multiply, divide
+
+def test_add():
+    assert add(2, 3) == 5
+    assert add(-1, 1) == 0
+
+def test_multiply():
+    assert multiply(3, 4) == 12
+    assert multiply(0, 5) == 0
+
+def test_divide():
+    assert divide(10, 2) == 5
+    with pytest.raises(ValueError):
+        divide(10, 0)