TST:add tests for the methods animate_propellant_mass and animate_fluid_volume and solve linters issues

Author: Bizo883

rocketpy/plots/motor_plots.py

@@ -528,7 +528,7 @@ def animate_propellant_mass(self, filename=None, fps=30):
         ----------
         filename : str | None, optional
             The path the animation should be saved to. By default None, in which
-            case the animation will be shown instead of saved.Supported file 
+            case the animation will be shown instead of saved.Supported file
             ending is: .gif
         fps : int, optional
             Frames per second for the animation. Default is 30.
@@ -567,7 +567,7 @@ def init():
 
         # Update per frame
         def update(frame_index):
-            line.set_data(times[:frame_index+1], values[:frame_index+1])
+            line.set_data(times[: frame_index + 1], values[: frame_index + 1])
             point.set_data([times[frame_index]], [values[frame_index]])
             return line, point
 

rocketpy/plots/tank_plots.py

@@ -231,12 +231,14 @@ def init():
 
         def update(frame_index):
             # Liquid part
-            line_liquid.set_data(times[:frame_index+1], liquid_values[:frame_index+1])
-            point_liquid.set_data(times[frame_index], liquid_values[frame_index])
+            line_liquid.set_data(
+                times[: frame_index + 1], liquid_values[: frame_index + 1]
+            )
+            point_liquid.set_data([times[frame_index]], [liquid_values[frame_index]])
 
             # Gas part
-            line_gas.set_data(times[:frame_index+1], gas_values[:frame_index+1])
-            point_gas.set_data(times[frame_index], gas_values[frame_index])
+            line_gas.set_data(times[: frame_index + 1], gas_values[: frame_index + 1])
+            point_gas.set_data([times[frame_index]], [gas_values[frame_index]])
 
             return line_liquid, line_gas, point_liquid, point_gas
 

tests/unit/test_plots.py

@@ -141,3 +141,33 @@ def update(frame):
 
     with pytest.raises(ValueError, match="Unsupported file ending"):
         show_or_save_animation(animation, "test.mp4")
+
+
+def test_animate_propellant_mass(cesaroni_m1670):
+    """Test that animate_propellant_mass saves a .gif file correctly."""
+
+    motor = cesaroni_m1670
+    animation = motor.plots.animate_propellant_mass(filename="cesaroni_m1670.gif")
+
+    # Check animation type
+    assert isinstance(animation, FuncAnimation)
+
+    # check if file exists
+    assert os.path.exists("cesaroni_m1670.gif")
+
+    os.remove("cesaroni_m1670.gif")
+
+
+def test_animate_fluid_volume(example_mass_flow_rate_based_tank_seblm):
+    """Test that animate_fluid_volume saves a .gif file correctly."""
+
+    tank = example_mass_flow_rate_based_tank_seblm
+    animation = tank.plots.animate_fluid_volume(filename="test_fluid_volume.gif")
+
+    # Check animation type
+    assert isinstance(animation, FuncAnimation)
+
+    # Check if file exists
+    assert os.path.exists("test_fluid_volume.gif")
+
+    os.remove("test_fluid_volume.gif")