added testing for pi

tests/functions/test_pi.py

@@ -0,0 +1,25 @@
+import pytest
+from fabelous_math import approximate_pi
+
+def test_approximate_pi():
+    # Test with a known precision value
+    precision = 10000
+    pi_approx = approximate_pi(precision)
+    assert isinstance(pi_approx, float), "The result should be a float"
+    assert pi_approx > 3.14, "The approximation of Pi should be greater than 3.14"
+    assert pi_approx < 3.15, "The approximation of Pi should be less than 3.15"
+
+def test_approximate_pi_with_low_precision():
+    # Test with a low precision value
+    precision = 100
+    pi_approx = approximate_pi(precision)
+    assert isinstance(pi_approx, float), "The result should be a float"
+    assert pi_approx > 3.0, "The approximation of Pi should be greater than 3.0"
+    assert pi_approx < 4.0, "The approximation of Pi should be less than 4.0"
+
+def test_approximate_pi_with_high_precision():
+    # Test with a high precision value
+    precision = 10000000
+    pi_approx = approximate_pi(precision)
+    assert isinstance(pi_approx, float), "The result should be a float"
+    assert pi_approx > 3.1415926533, "The approximation of Pi should be greater than the known value of Pi"