diff --git a/coverage-report.pdf b/coverage-report.pdf
new file mode 100644
index 0000000..080c203
Binary files /dev/null and b/coverage-report.pdf differ
diff --git a/diffusion2d.py b/diffusion2d.py
index 51a07f2..c49a76c 100644
--- a/diffusion2d.py
+++ b/diffusion2d.py
@@ -38,6 +38,9 @@ def __init__(self):
         self.dt = None
 
     def initialize_domain(self, w=10., h=10., dx=0.1, dy=0.1):
+        for name, value in {"w": w, "h": h, "dx": dx, "dy": dy}.items():
+            assert isinstance(value, float), f"{name} must be of type float, got {type(value).__name__}."
+
         self.w = w
         self.h = h
         self.dx = dx
@@ -45,7 +48,9 @@ def initialize_domain(self, w=10., h=10., dx=0.1, dy=0.1):
         self.nx = int(w / dx)
         self.ny = int(h / dy)
 
-    def initialize_physical_parameters(self, d=4., T_cold=300, T_hot=700):
+    def initialize_physical_parameters(self, d=4., T_cold=300.0, T_hot=700.0):
+        for name, value in {"d": d, "T_cold": T_cold, "T_hot": T_hot}.items():
+            assert isinstance(value, float), f"{name} must be of type float, got {type(value).__name__}."
         self.D = d
         self.T_cold = T_cold
         self.T_hot = T_hot
diff --git a/requirements.txt b/requirements.txt
new file mode 100644
index 0000000..8f87fb4
--- /dev/null
+++ b/requirements.txt
@@ -0,0 +1,4 @@
+numpy
+matplotlib
+pytest
+coverage
\ No newline at end of file
diff --git a/tests/integration/test_diffusion2d.py b/tests/integration/test_diffusion2d.py
index fd026b4..3296771 100644
--- a/tests/integration/test_diffusion2d.py
+++ b/tests/integration/test_diffusion2d.py
@@ -3,17 +3,33 @@
 """
 
 from diffusion2d import SolveDiffusion2D
-
+import pytest
 
 def test_initialize_physical_parameters():
     """
     Checks function SolveDiffusion2D.initialize_domain
     """
     solver = SolveDiffusion2D()
+    w, h, dx, dy = 10.0, 10.0, 0.1, 0.1
+    d = 4.0
+    expected_dt = 0.000625
+    
+    solver.initialize_domain(w, h, dx, dy)
+    solver.initialize_physical_parameters(d=d)
+    
+    assert solver.dt == pytest.approx(expected_dt)
 
 
 def test_set_initial_condition():
     """
-    Checks function SolveDiffusion2D.get_initial_function
+    Checks function SolveDiffusion2D.set_initial_condition
     """
     solver = SolveDiffusion2D()
+    solver.initialize_domain(w=10.0, h=10.0, dx=0.1, dy=0.1)
+    solver.initialize_physical_parameters(d=4.0, T_cold=300.0, T_hot=700.0)
+    
+    u = solver.set_initial_condition()
+    
+    assert u.shape == (100, 100)
+    assert u[50, 50] == 700.0
+    assert u[0, 0] == 300.0
\ No newline at end of file
diff --git a/tests/unit/test_diffusion2d_functions.py b/tests/unit/test_diffusion2d_functions.py
index c4277ff..493d674 100644
--- a/tests/unit/test_diffusion2d_functions.py
+++ b/tests/unit/test_diffusion2d_functions.py
@@ -3,24 +3,46 @@
 """
 
 from diffusion2d import SolveDiffusion2D
+import pytest
+import numpy as np
 
-
-def test_initialize_domain():
+def test_initialize_physical_parameters():
     """
-    Check function SolveDiffusion2D.initialize_domain
+    Checks function SolveDiffusion2D.initialize_physical_parameters
     """
     solver = SolveDiffusion2D()
 
+    w, h, dx, dy = 10.0, 10.0, 0.1, 0.1
+    d = 4.0
+    expected_dt = 0.000625
+    
+    solver.initialize_domain(w, h, dx, dy)
+    solver.initialize_physical_parameters(d=d)
 
-def test_initialize_physical_parameters():
-    """
-    Checks function SolveDiffusion2D.initialize_domain
-    """
-    solver = SolveDiffusion2D()
+    assert solver.dt == pytest.approx(expected_dt)
 
 
 def test_set_initial_condition():
     """
-    Checks function SolveDiffusion2D.get_initial_function
+    Checks function SolveDiffusion2D.set_initial_condition
     """
     solver = SolveDiffusion2D()
+
+    w, h, dx, dy = 10.0, 10.0, 0.1, 0.1
+    T_cold = 300.0
+    T_hot = 700.0
+    solver.initialize_domain(w, h, dx, dy)
+    solver.initialize_physical_parameters(T_cold=T_cold, T_hot=T_hot)
+    
+    nx, ny = 100, 100
+    expected_u = T_cold * np.ones((nx, ny))
+    r, cx, cy = 2, 5, 5
+    r2 = r ** 2
+    for i in range(nx):
+        for j in range(ny):
+            p2 = (i * dx - cx) ** 2 + (j * dy - cy) ** 2
+            if p2 < r2:
+                expected_u[i, j] = T_hot
+    
+    actual_u = solver.set_initial_condition()
+    assert np.allclose(actual_u, expected_u)
\ No newline at end of file
diff --git a/tox.toml b/tox.toml
new file mode 100644
index 0000000..72e0fc8
--- /dev/null
+++ b/tox.toml
@@ -0,0 +1,7 @@
+requires = ["tox>=4"]
+env_list = ["pytest_testing"]
+
+[env.pytest_testing]
+description = "Run pytest"
+deps = ["-r requirements.txt"]
+commands = [["python", "-m", "pytest"]]
\ No newline at end of file