Increase test coverage

Author: ufechner7

ext/VortexStepMethodControlPlotsExt.jl

@@ -79,7 +79,7 @@ function VortexStepMethod.save_plot(fig, save_path, title; data_type=".pdf")
 end
 
 """
-    show_plot(fig; dpi=130)
+    show_plot(fig::plt.Figure; dpi=130)
 
 Display a plot at specified DPI.
 
@@ -89,7 +89,8 @@ Display a plot at specified DPI.
 # Keyword arguments
 - `dpi`: Dots per inch for the figure (default: 130)
 """
-function VortexStepMethod.show_plot(fig; dpi=130)
+function VortexStepMethod.show_plot(fig::plt.Figure; dpi=130)
+    fig.set_dpi(dpi)
     plt.display(fig)
 end
 

test/plotting/test_plotting.jl

@@ -1,5 +1,6 @@
 backend = if "plot-controlplots" in ARGS
     using ControlPlots
+    import ControlPlots: plt
     "ControlPlots"
 else
     using CairoMakie
@@ -213,5 +214,19 @@ end
     else
         @test fig !== nothing
     end
+
+    if backend == "ControlPlots"
+        fig_dpi = plt.figure()
+        default_dpi = fig_dpi.get_dpi()
+        @test default_dpi != 173
+
+        show_plot(fig_dpi; dpi=173)
+        @test fig_dpi.get_dpi() == 173
+
+        # Also verify the default keyword value is applied.
+        show_plot(fig_dpi)
+        @test fig_dpi.get_dpi() == 130
+        plt.close(fig_dpi)
+    end
 end
 nothing