From 81110372451ea4717c30812e15ad4e3b469a4c1b Mon Sep 17 00:00:00 2001
From: bennibolm <benjamin.bolm@gmx.de>
Date: Sat, 11 May 2024 12:27:36 +0200
Subject: [PATCH] Add test for saving deviations for positivity limiter
 (non-linear)

---
 ...ixir_euler_kelvin_helmholtz_instability_sc_subcell.jl | 3 ++-
 test/test_tree_2d_euler.jl                               | 9 ++++++++-
 2 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/examples/tree_2d_dgsem/elixir_euler_kelvin_helmholtz_instability_sc_subcell.jl b/examples/tree_2d_dgsem/elixir_euler_kelvin_helmholtz_instability_sc_subcell.jl
index 1817672778a..c9024d7f734 100644
--- a/examples/tree_2d_dgsem/elixir_euler_kelvin_helmholtz_instability_sc_subcell.jl
+++ b/examples/tree_2d_dgsem/elixir_euler_kelvin_helmholtz_instability_sc_subcell.jl
@@ -83,7 +83,8 @@ callbacks = CallbackSet(summary_callback,
 ###############################################################################
 # run the simulation
 
-stage_callbacks = (SubcellLimiterIDPCorrection(), BoundsCheckCallback(save_errors = false))
+stage_callbacks = (SubcellLimiterIDPCorrection(),
+                   BoundsCheckCallback(save_errors = false, interval = 100))
 
 sol = Trixi.solve(ode, Trixi.SimpleSSPRK33(stage_callbacks = stage_callbacks);
                   dt = 1.0, # solve needs some value here but it will be overwritten by the stepsize_callback
diff --git a/test/test_tree_2d_euler.jl b/test/test_tree_2d_euler.jl
index 9a40b1a4d7d..a004d1452b7 100644
--- a/test/test_tree_2d_euler.jl
+++ b/test/test_tree_2d_euler.jl
@@ -628,6 +628,7 @@ end
 end
 
 @trixi_testset "elixir_euler_kelvin_helmholtz_instability_sc_subcell.jl" begin
+    rm(joinpath("out", "deviations.txt"), force = true)
     @test_trixi_include(joinpath(EXAMPLES_DIR,
                                  "elixir_euler_kelvin_helmholtz_instability_sc_subcell.jl"),
                         l2=[
@@ -642,7 +643,13 @@ end
                             0.5822547982757897,
                             0.7300051017382696,
                         ],
-                        tspan=(0.0, 2.0))
+                        tspan=(0.0, 2.0),
+                        coverage_override=(maxiters = 7,),
+                        save_errors=true)
+    lines = readlines(joinpath("out", "deviations.txt"))
+    @test lines[1] == "# iter, simu_time, rho_min, pressure_min"
+    # Run without (with) coverage takes 745 (7) time steps
+    @test startswith(lines[end], "7")
     # Ensure that we do not have excessive memory allocations
     # (e.g., from type instabilities)
     let