diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..560f82c
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,11 @@
+__pycache__/
+
+.venv/
+venv/
+
+.pytest_cache/
+
+.coverage
+htmlcov/
+
+.tox/
diff --git a/coverage-report.pdf b/coverage-report.pdf
new file mode 100644
index 0000000..caccba6
Binary files /dev/null and b/coverage-report.pdf differ
diff --git a/diffusion2d.py b/diffusion2d.py
index 51a07f2..3394fb8 100644
--- a/diffusion2d.py
+++ b/diffusion2d.py
@@ -38,6 +38,11 @@ def __init__(self):
         self.dt = None
 
     def initialize_domain(self, w=10., h=10., dx=0.1, dy=0.1):
+        assert isinstance(w, float)
+        assert isinstance(h, float)
+        assert isinstance(dx, float)
+        assert isinstance(dy, float)
+
         self.w = w
         self.h = h
         self.dx = dx
@@ -45,7 +50,11 @@ 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):
+        assert isinstance(d, float)
+        assert isinstance(T_cold, float)
+        assert isinstance(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..4c573bc
--- /dev/null
+++ b/requirements.txt
@@ -0,0 +1,5 @@
+numpy>=1.26.0
+matplotlib>=3.8.0
+pytest>=9.0.0
+coverage>=7.13.1
+tox>=4.23.2
diff --git a/tests/integration/test_diffusion2d.py b/tests/integration/test_diffusion2d.py
index fd026b4..8b7e7b6 100644
--- a/tests/integration/test_diffusion2d.py
+++ b/tests/integration/test_diffusion2d.py
@@ -11,9 +11,36 @@ def test_initialize_physical_parameters():
     """
     solver = SolveDiffusion2D()
 
+    solver.initialize_domain(w=10.0, h=10.0, dx=1.0, dy=1.0)
+    solver.initialize_physical_parameters(d=2.0, T_cold=300.0, T_hot=700.0)
+
+    expected_dt = 0.125
+
+    assert solver.dt == expected_dt
+    
+    assert solver.D == 2.0
+    assert solver.T_cold == 300.0
+    assert solver.T_hot == 700.0
+
 
 def test_set_initial_condition():
     """
     Checks function SolveDiffusion2D.get_initial_function
     """
     solver = SolveDiffusion2D()
+
+    solver.initialize_domain(w=10.0, h=10.0, dx=1.0, dy=1.0)
+    solver.initialize_physical_parameters(d=1.0, T_cold=0.0, T_hot=100.0)
+
+    u = solver.set_initial_condition()
+
+    # shape
+    assert u.shape == (solver.nx, solver.ny)
+
+    # center index
+    cx_index = int(5 / solver.dx)
+    cy_index = int(5 / solver.dy)
+
+    # check center and corner values
+    assert u[cx_index, cy_index] == solver.T_hot
+    assert u[0,0] == solver.T_cold
\ No newline at end of file
diff --git a/tests/unit/test_diffusion2d_functions.py b/tests/unit/test_diffusion2d_functions.py
index c4277ff..60e5a07 100644
--- a/tests/unit/test_diffusion2d_functions.py
+++ b/tests/unit/test_diffusion2d_functions.py
@@ -11,16 +11,74 @@ def test_initialize_domain():
     """
     solver = SolveDiffusion2D()
 
+    # input values
+    w = 12.0
+    h = 8.0
+    dx = 0.5
+    dy = 0.25
+
+    # expected results
+    expected_nx = 24
+    expected_ny = 32
+
+    # call function under test
+    solver.initialize_domain(w=w, h=h, dx=dx, dy=dy)
+
+    # assertions
+    assert solver.nx == expected_nx
+    assert solver.ny == expected_ny
 
 def test_initialize_physical_parameters():
     """
-    Checks function SolveDiffusion2D.initialize_domain
+    Check function SolveDiffusion2D.initialize_physical_parameters
     """
     solver = SolveDiffusion2D()
 
+    solver.dx = 1.0
+    solver.dy = 2.0
+
+    d = 2.0
+    T_cold = 300.0
+    T_hot = 700.0
+
+    # dx² = 1
+    # dy² = 4
+    #
+    # dt = (1 * 4) / (2 * 2 * (1 + 4))
+    # dt = 4 / 20
+    # dt = 0.2
+    # expected result
+    expected_dt = 0.2
+
+    solver.initialize_physical_parameters(d=d, T_cold=T_cold, T_hot=T_hot)
+
+    # assertions
+    assert solver.D == d
+    assert solver.T_cold == T_cold
+    assert solver.T_hot == T_hot
+    assert solver.dt == expected_dt
 
 def test_set_initial_condition():
     """
-    Checks function SolveDiffusion2D.get_initial_function
+    Check function SolveDiffusion2D.set_initial_condition
     """
     solver = SolveDiffusion2D()
+
+    solver.nx = 10
+    solver.ny = 10
+    solver.dx = 1.0
+    solver.dy = 1.0
+    solver.T_cold = 0.0
+    solver.T_hot = 100.0
+
+    # call function under test
+    u = solver.set_initial_condition()
+
+    # basic shape check
+    assert u.shape == (10, 10)
+
+    # center should be hot
+    assert u[5, 5] == solver.T_hot
+
+    # corner should be cold
+    assert u[0, 0] == solver.T_cold
diff --git a/tox.toml b/tox.toml
new file mode 100644
index 0000000..2e640b4
--- /dev/null
+++ b/tox.toml
@@ -0,0 +1,19 @@
+[tool.tox]
+env_list = ["py", "coverage"]
+skips_dist = true
+
+[tool.tox.testenv.py]
+description = "Run unit and integration tests"
+deps = ["-r requirements.txt"]
+commands = [
+    "python -m pytest tests/unit",
+    "python -m pytest tests/integration"
+]
+
+[tool.tox.testenv.coverage]
+description = "Generate coverage report"
+deps = ["-r requirements.txt", "coverage"]
+commands = [
+    "coverage run -m pytest",
+    "coverage html"
+]