diff --git a/coverage-report.pdf b/coverage-report.pdf
new file mode 100644
index 0000000..83960e4
Binary files /dev/null and b/coverage-report.pdf differ
diff --git a/diffusion2d.py b/diffusion2d.py
index 51a07f2..6c9133c 100644
--- a/diffusion2d.py
+++ b/diffusion2d.py
@@ -38,6 +38,10 @@ def __init__(self):
         self.dt = None
 
     def initialize_domain(self, w=10., h=10., dx=0.1, dy=0.1):
+        assert type(w) == float
+        assert type(h) == float
+        assert type(dx) == float
+        assert type(dy) == float
         self.w = w
         self.h = h
         self.dx = dx
@@ -45,7 +49,10 @@ 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., T_hot=700.):
+        assert type(d) == float
+        assert type(T_cold) == float
+        assert type(T_hot) == float
         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..d8ab3c2
--- /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..1a4ccd9 100644
--- a/tests/integration/test_diffusion2d.py
+++ b/tests/integration/test_diffusion2d.py
@@ -3,6 +3,7 @@
 """
 
 from diffusion2d import SolveDiffusion2D
+import numpy as np
 
 
 def test_initialize_physical_parameters():
@@ -11,9 +12,39 @@ def test_initialize_physical_parameters():
     """
     solver = SolveDiffusion2D()
 
+    w = 10.
+    h = 10.
+    dx = 0.5
+    dy = 0.5
+    solver.initialize_domain(w=w, h=h, dx=dx, dy=dy)
+
+    d = 2.
+    T_cold = 150.
+    T_hot = 350.
+    solver.initialize_physical_parameters(d=d, T_cold=T_cold, T_hot=T_hot)
+    expected_result = 0.03125
+
+    assert solver.dt == expected_result
+
 
 def test_set_initial_condition():
     """
     Checks function SolveDiffusion2D.get_initial_function
     """
+    # compute a similar `u` array for defined parameters
+    w = 12.
+    h = 18.
+    dx = 2.
+    dy = 6.
+    T_cold = 6.
+    nx = int(w / dx)
+    ny = int(h / dy)
     solver = SolveDiffusion2D()
+    solver.initialize_domain(w=w, h=h, dx=dx, dy=dy)
+    solver.initialize_physical_parameters(T_cold=T_cold)
+    solver.cx = 4
+    solver.cy = 2
+    expected_u = solver.T_cold * np.ones((nx, ny)).copy()
+    
+    computed_u = solver.set_initial_condition()
+    assert computed_u.all() == expected_u.all()
diff --git a/tests/unit/test_diffusion2d_functions.py b/tests/unit/test_diffusion2d_functions.py
index c4277ff..3adac82 100644
--- a/tests/unit/test_diffusion2d_functions.py
+++ b/tests/unit/test_diffusion2d_functions.py
@@ -3,24 +3,53 @@
 """
 
 from diffusion2d import SolveDiffusion2D
+import numpy as np
 
 
 def test_initialize_domain():
     """
     Check function SolveDiffusion2D.initialize_domain
     """
+    w = 100.
+    h = 120.
+    dx = 0.5
+    dy = 0.5
+    expected_nx = 200.
+    expected_ny = 240.
     solver = SolveDiffusion2D()
 
+    solver.initialize_domain(w=w, h=h, dx=dx, dy=dy)
+    assert solver.nx == expected_nx
+    assert solver.ny == expected_ny
 
 def test_initialize_physical_parameters():
     """
     Checks function SolveDiffusion2D.initialize_domain
     """
+    d = 2.
+    T_cold = 150.
+    T_hot = 350.
     solver = SolveDiffusion2D()
+    solver.dx = 0.5
+    solver.dy = 0.5
+    expected_dt = 0.03125
 
+    solver.initialize_physical_parameters(d=d, T_cold=T_cold, T_hot=T_hot)
+    assert solver.dt == expected_dt
 
 def test_set_initial_condition():
     """
     Checks function SolveDiffusion2D.get_initial_function
     """
     solver = SolveDiffusion2D()
+    solver.T_cold = 6
+    solver.nx = 6
+    solver.ny = 3
+    solver.dx = 9
+    solver.dy = 3
+    solver.cx = 4
+    solver.cy = 2
+    expected_result = solver.T_cold * np.ones((solver.nx, solver.ny)).copy()
+    
+    actual_result = solver.set_initial_condition()
+    assert actual_result.all() == expected_result.all()
diff --git a/tox.toml b/tox.toml
new file mode 100644
index 0000000..4f7089a
--- /dev/null
+++ b/tox.toml
@@ -0,0 +1,7 @@
+requires = ["tox>=4"]
+env_list = ["pytest_testing"]
+
+[env.pytest_testing]
+description = "Run pytest"
+deps = ["-rrequirements.txt"]
+commands = [["python3", "-m", "pytest"]]
\ No newline at end of file