From 1635d318b2bf68f9da2bd9392e8ef782c7e562c6 Mon Sep 17 00:00:00 2001
From: Erik Faulhaber <44124897+efaulhaber@users.noreply.github.com>
Date: Sat, 18 Nov 2023 16:20:32 +0100
Subject: [PATCH] Throw error in `trixi_include` when assignment is not found
 (#1737)

* Throw error in `trixi_include` when assignment is not found

* Add tests for `trixi_include`

* Reformat

* Update test/test_unit.jl

Co-authored-by: Michael Schlottke-Lakemper <michael@sloede.com>

* Add more comments

* Fix convergence tests and `trixi_include` with `skip_coverage`

* Fix tests trying to override non-existing assignments

* Add `maxiters` to restart elixirs and exclude for coverage tests

* Reformat

* Reformat

* Add comment and more specific error in  `convergence_test`

* Update src/auxiliary/special_elixirs.jl

Co-authored-by: Michael Schlottke-Lakemper <michael@sloede.com>

* Update src/auxiliary/special_elixirs.jl

Co-authored-by: Michael Schlottke-Lakemper <michael@sloede.com>

* Fix tests

* Use `@test_nowarn_mod`

* Fix tests

* Fix tests (again)

---------

Co-authored-by: Michael Schlottke-Lakemper <michael@sloede.com>
Co-authored-by: Hendrik Ranocha <ranocha@users.noreply.github.com>
---
 .../elixir_advection_restart.jl               |  2 +-
 .../elixir_advection_restart.jl               |  2 +-
 .../elixir_advection_restart.jl               |  2 +-
 .../elixir_advection_restart.jl               |  2 +-
 .../tree_2d_dgsem/elixir_advection_restart.jl |  2 +-
 .../tree_3d_dgsem/elixir_advection_restart.jl |  2 +-
 .../elixir_euler_restart.jl                   |  2 +-
 src/auxiliary/special_elixirs.jl              | 47 +++++++--
 test/test_mpi_p4est_2d.jl                     |  5 +-
 test/test_mpi_p4est_3d.jl                     |  5 +-
 test/test_p4est_2d.jl                         |  9 +-
 test/test_p4est_3d.jl                         |  9 +-
 test/test_special_elixirs.jl                  | 13 +--
 test/test_structured_2d.jl                    | 15 ++-
 test/test_structured_3d.jl                    |  5 +-
 test/test_threaded.jl                         |  5 +-
 test/test_tree_3d_advection.jl                |  5 +-
 test/test_trixi.jl                            |  2 +-
 test/test_unit.jl                             | 97 +++++++++++++++++++
 test/test_unstructured_2d.jl                  |  5 +-
 test/test_visualization.jl                    |  5 +-
 21 files changed, 196 insertions(+), 45 deletions(-)

diff --git a/examples/p4est_2d_dgsem/elixir_advection_restart.jl b/examples/p4est_2d_dgsem/elixir_advection_restart.jl
index 4f43e122ab3..0f573714c1f 100644
--- a/examples/p4est_2d_dgsem/elixir_advection_restart.jl
+++ b/examples/p4est_2d_dgsem/elixir_advection_restart.jl
@@ -31,7 +31,7 @@ save_solution.condition.save_initial_solution = false
 
 integrator = init(ode, CarpenterKennedy2N54(williamson_condition = false),
                   dt = dt, # solve needs some value here but it will be overwritten by the stepsize_callback
-                  save_everystep = false, callback = callbacks);
+                  save_everystep = false, callback = callbacks, maxiters = 100_000);
 
 # Get the last time index and work with that.
 load_timestep!(integrator, restart_filename)
diff --git a/examples/p4est_3d_dgsem/elixir_advection_restart.jl b/examples/p4est_3d_dgsem/elixir_advection_restart.jl
index cd97d69d692..b3dead42399 100644
--- a/examples/p4est_3d_dgsem/elixir_advection_restart.jl
+++ b/examples/p4est_3d_dgsem/elixir_advection_restart.jl
@@ -29,7 +29,7 @@ save_solution.condition.save_initial_solution = false
 
 integrator = init(ode, CarpenterKennedy2N54(williamson_condition = false),
                   dt = dt, # solve needs some value here but it will be overwritten by the stepsize_callback
-                  save_everystep = false, callback = callbacks);
+                  save_everystep = false, callback = callbacks, maxiters = 100_000);
 
 # Get the last time index and work with that.
 load_timestep!(integrator, restart_filename)
diff --git a/examples/structured_2d_dgsem/elixir_advection_restart.jl b/examples/structured_2d_dgsem/elixir_advection_restart.jl
index 19863faae8d..0accbdba702 100644
--- a/examples/structured_2d_dgsem/elixir_advection_restart.jl
+++ b/examples/structured_2d_dgsem/elixir_advection_restart.jl
@@ -30,7 +30,7 @@ save_solution.condition.save_initial_solution = false
 
 integrator = init(ode, CarpenterKennedy2N54(williamson_condition = false),
                   dt = dt, # solve needs some value here but it will be overwritten by the stepsize_callback
-                  save_everystep = false, callback = callbacks);
+                  save_everystep = false, callback = callbacks, maxiters = 100_000);
 
 # Get the last time index and work with that.
 load_timestep!(integrator, restart_filename)
diff --git a/examples/structured_3d_dgsem/elixir_advection_restart.jl b/examples/structured_3d_dgsem/elixir_advection_restart.jl
index e81ad5d6430..e516d794df8 100644
--- a/examples/structured_3d_dgsem/elixir_advection_restart.jl
+++ b/examples/structured_3d_dgsem/elixir_advection_restart.jl
@@ -29,7 +29,7 @@ save_solution.condition.save_initial_solution = false
 
 integrator = init(ode, CarpenterKennedy2N54(williamson_condition = false),
                   dt = dt, # solve needs some value here but it will be overwritten by the stepsize_callback
-                  save_everystep = false, callback = callbacks);
+                  save_everystep = false, callback = callbacks, maxiters = 100_000);
 
 # Get the last time index and work with that.
 load_timestep!(integrator, restart_filename)
diff --git a/examples/tree_2d_dgsem/elixir_advection_restart.jl b/examples/tree_2d_dgsem/elixir_advection_restart.jl
index 770629bb15e..e0d1003f524 100644
--- a/examples/tree_2d_dgsem/elixir_advection_restart.jl
+++ b/examples/tree_2d_dgsem/elixir_advection_restart.jl
@@ -29,7 +29,7 @@ save_solution.condition.save_initial_solution = false
 
 integrator = init(ode, alg,
                   dt = dt, # solve needs some value here but it will be overwritten by the stepsize_callback
-                  save_everystep = false, callback = callbacks; ode_default_options()...)
+                  callback = callbacks, maxiters = 100_000; ode_default_options()...)
 
 # Load saved context for adaptive time integrator
 if integrator.opts.adaptive
diff --git a/examples/tree_3d_dgsem/elixir_advection_restart.jl b/examples/tree_3d_dgsem/elixir_advection_restart.jl
index f81e013fc0a..a53f4ebf5b1 100644
--- a/examples/tree_3d_dgsem/elixir_advection_restart.jl
+++ b/examples/tree_3d_dgsem/elixir_advection_restart.jl
@@ -27,7 +27,7 @@ save_solution.condition.save_initial_solution = false
 
 integrator = init(ode, CarpenterKennedy2N54(williamson_condition = false),
                   dt = dt, # solve needs some value here but it will be overwritten by the stepsize_callback
-                  save_everystep = false, callback = callbacks);
+                  save_everystep = false, callback = callbacks, maxiters = 100_000);
 
 # Get the last time index and work with that.
 load_timestep!(integrator, restart_filename)
diff --git a/examples/unstructured_2d_dgsem/elixir_euler_restart.jl b/examples/unstructured_2d_dgsem/elixir_euler_restart.jl
index 4d6af65b8a4..c1908691902 100644
--- a/examples/unstructured_2d_dgsem/elixir_euler_restart.jl
+++ b/examples/unstructured_2d_dgsem/elixir_euler_restart.jl
@@ -29,7 +29,7 @@ save_solution.condition.save_initial_solution = false
 
 integrator = init(ode, CarpenterKennedy2N54(williamson_condition = false),
                   dt = dt, # solve needs some value here but it will be overwritten by the stepsize_callback
-                  save_everystep = false, callback = callbacks);
+                  save_everystep = false, callback = callbacks, maxiters = 100_000);
 
 # Get the last time index and work with that.
 load_timestep!(integrator, restart_filename)
diff --git a/src/auxiliary/special_elixirs.jl b/src/auxiliary/special_elixirs.jl
index 25bca8939ce..5fdd9aea0c5 100644
--- a/src/auxiliary/special_elixirs.jl
+++ b/src/auxiliary/special_elixirs.jl
@@ -20,7 +20,7 @@ providing examples with sensible default values for users.
 
 Before replacing assignments in `elixir`, the keyword argument `maxiters` is inserted
 into calls to `solve` and `Trixi.solve` with it's default value used in the SciML ecosystem
-for ODEs, see the "Miscellaneous" section of the 
+for ODEs, see the "Miscellaneous" section of the
 [documentation](https://docs.sciml.ai/DiffEqDocs/stable/basics/common_solver_opts/).
 
 # Examples
@@ -36,6 +36,16 @@ julia> redirect_stdout(devnull) do
 ```
 """
 function trixi_include(mod::Module, elixir::AbstractString; kwargs...)
+    # Check that all kwargs exist as assignments
+    code = read(elixir, String)
+    expr = Meta.parse("begin \n$code \nend")
+    expr = insert_maxiters(expr)
+
+    for (key, val) in kwargs
+        # This will throw an error when `key` is not found
+        find_assignment(expr, key)
+    end
+
     # Print information on potential wait time only in non-parallel case
     if !mpi_isparallel()
         @info "You just called `trixi_include`. Julia may now compile the code, please be patient."
@@ -243,6 +253,7 @@ end
 function find_assignment(expr, destination)
     # declare result to be able to assign to it in the closure
     local result
+    found = false
 
     # find explicit and keyword assignments
     walkexpr(expr) do x
@@ -250,12 +261,17 @@ function find_assignment(expr, destination)
             if (x.head === Symbol("=") || x.head === :kw) &&
                x.args[1] === Symbol(destination)
                 result = x.args[2]
+                found = true
                 # dump(x)
             end
         end
         return x
     end
 
+    if !found
+        throw(ArgumentError("assignment `$destination` not found in expression"))
+    end
+
     result
 end
 
@@ -274,17 +290,28 @@ function extract_initial_resolution(elixir, kwargs)
             return initial_refinement_level
         end
     catch e
-        if isa(e, UndefVarError)
-            # get cells_per_dimension from the elixir
-            cells_per_dimension = eval(find_assignment(expr, :cells_per_dimension))
-
-            if haskey(kwargs, :cells_per_dimension)
-                return kwargs[:cells_per_dimension]
-            else
-                return cells_per_dimension
+        # If `initial_refinement_level` is not found, we will get an `ArgumentError`
+        if isa(e, ArgumentError)
+            try
+                # get cells_per_dimension from the elixir
+                cells_per_dimension = eval(find_assignment(expr, :cells_per_dimension))
+
+                if haskey(kwargs, :cells_per_dimension)
+                    return kwargs[:cells_per_dimension]
+                else
+                    return cells_per_dimension
+                end
+            catch e2
+                # If `cells_per_dimension` is not found either
+                if isa(e2, ArgumentError)
+                    throw(ArgumentError("`convergence_test` requires the elixir to define " *
+                                        "`initial_refinement_level` or `cells_per_dimension`"))
+                else
+                    rethrow()
+                end
             end
         else
-            throw(e)
+            rethrow()
         end
     end
 end
diff --git a/test/test_mpi_p4est_2d.jl b/test/test_mpi_p4est_2d.jl
index 1edbce8f6c8..da90537fcfd 100644
--- a/test/test_mpi_p4est_2d.jl
+++ b/test/test_mpi_p4est_2d.jl
@@ -69,7 +69,10 @@ const EXAMPLES_DIR = pkgdir(Trixi, "examples", "p4est_2d_dgsem")
     @trixi_testset "elixir_advection_restart.jl" begin
         @test_trixi_include(joinpath(EXAMPLES_DIR, "elixir_advection_restart.jl"),
                             l2=[4.507575525876275e-6],
-                            linf=[6.21489667023134e-5])
+                            linf=[6.21489667023134e-5],
+                            # With the default `maxiters = 1` in coverage tests,
+                            # there would be no time steps after the restart.
+                            coverage_override=(maxiters = 100_000,))
     end
 
     @trixi_testset "elixir_euler_source_terms_nonconforming_unstructured_flag.jl" begin
diff --git a/test/test_mpi_p4est_3d.jl b/test/test_mpi_p4est_3d.jl
index 8082930b3b4..75f43650082 100644
--- a/test/test_mpi_p4est_3d.jl
+++ b/test/test_mpi_p4est_3d.jl
@@ -63,7 +63,10 @@ const EXAMPLES_DIR = pkgdir(Trixi, "examples", "p4est_3d_dgsem")
     @trixi_testset "elixir_advection_restart.jl" begin
         @test_trixi_include(joinpath(EXAMPLES_DIR, "elixir_advection_restart.jl"),
                             l2=[0.002590388934758452],
-                            linf=[0.01840757696885409])
+                            linf=[0.01840757696885409],
+                            # With the default `maxiters = 1` in coverage tests,
+                            # there would be no time steps after the restart.
+                            coverage_override=(maxiters = 100_000,))
     end
 
     @trixi_testset "elixir_advection_cubed_sphere.jl" begin
diff --git a/test/test_p4est_2d.jl b/test/test_p4est_2d.jl
index 07c6d02bbcd..db34aecc168 100644
--- a/test/test_p4est_2d.jl
+++ b/test/test_p4est_2d.jl
@@ -94,7 +94,10 @@ end
 @trixi_testset "elixir_advection_restart.jl" begin
     @test_trixi_include(joinpath(EXAMPLES_DIR, "elixir_advection_restart.jl"),
                         l2=[4.507575525876275e-6],
-                        linf=[6.21489667023134e-5])
+                        linf=[6.21489667023134e-5],
+                        # With the default `maxiters = 1` in coverage tests,
+                        # there would be no time steps after the restart.
+                        coverage_override=(maxiters = 100_000,))
     # Ensure that we do not have excessive memory allocations
     # (e.g., from type instabilities)
     let
@@ -216,8 +219,8 @@ end
                         ],
                         surface_flux=flux_hlle,
                         tspan=(0.0, 0.3))
-    # Ensure that we do not have excessive memory allocations 
-    # (e.g., from type instabilities) 
+    # Ensure that we do not have excessive memory allocations
+    # (e.g., from type instabilities)
     let
         t = sol.t[end]
         u_ode = sol.u[end]
diff --git a/test/test_p4est_3d.jl b/test/test_p4est_3d.jl
index 346c61c7448..f2467f30204 100644
--- a/test/test_p4est_3d.jl
+++ b/test/test_p4est_3d.jl
@@ -110,7 +110,10 @@ end
 @trixi_testset "elixir_advection_restart.jl" begin
     @test_trixi_include(joinpath(EXAMPLES_DIR, "elixir_advection_restart.jl"),
                         l2=[0.002590388934758452],
-                        linf=[0.01840757696885409])
+                        linf=[0.01840757696885409],
+                        # With the default `maxiters = 1` in coverage tests,
+                        # there would be no time steps after the restart.
+                        coverage_override=(maxiters = 100_000,))
     # Ensure that we do not have excessive memory allocations
     # (e.g., from type instabilities)
     let
@@ -305,8 +308,8 @@ end
                         ],
                         tspan=(0.0, 0.3),
                         surface_flux=flux_hlle)
-    # Ensure that we do not have excessive memory allocations 
-    # (e.g., from type instabilities) 
+    # Ensure that we do not have excessive memory allocations
+    # (e.g., from type instabilities)
     let
         t = sol.t[end]
         u_ode = sol.u[end]
diff --git a/test/test_special_elixirs.jl b/test/test_special_elixirs.jl
index 85671002ba6..ba670a6025e 100644
--- a/test/test_special_elixirs.jl
+++ b/test/test_special_elixirs.jl
@@ -92,8 +92,7 @@ coverage = occursin("--code-coverage", cmd) && !occursin("--code-coverage=none",
         # the convergence test logic
         @test_nowarn_mod convergence_test(@__MODULE__,
                                           joinpath(EXAMPLES_DIR, "tree_2d_dgsem",
-                                                   "elixir_advection_basic.jl"), 2,
-                                          tspan = (0.0, 0.01))
+                                                   "elixir_advection_basic.jl"), 2)
         @test_nowarn_mod convergence_test(@__MODULE__,
                                           joinpath(EXAMPLES_DIR, "tree_2d_dgsem",
                                                    "elixir_advection_extended.jl"), 2,
@@ -101,12 +100,10 @@ coverage = occursin("--code-coverage", cmd) && !occursin("--code-coverage=none",
                                           tspan = (0.0, 0.1))
         @test_nowarn_mod convergence_test(@__MODULE__,
                                           joinpath(EXAMPLES_DIR, "structured_2d_dgsem",
-                                                   "elixir_advection_basic.jl"), 2,
-                                          tspan = (0.0, 0.01))
+                                                   "elixir_advection_basic.jl"), 2)
         @test_nowarn_mod convergence_test(@__MODULE__,
                                           joinpath(EXAMPLES_DIR, "structured_2d_dgsem",
-                                                   "elixir_advection_coupled.jl"), 2,
-                                          tspan = (0.0, 0.01))
+                                                   "elixir_advection_coupled.jl"), 2)
         @test_nowarn_mod convergence_test(@__MODULE__,
                                           joinpath(EXAMPLES_DIR, "structured_2d_dgsem",
                                                    "elixir_advection_extended.jl"), 2,
@@ -345,8 +342,8 @@ end
     end
 
     @timed_testset "elixir_euler_ad.jl" begin
-        @test_trixi_include(joinpath(examples_dir(), "special_elixirs",
-                                     "elixir_euler_ad.jl"))
+        @test_nowarn_mod trixi_include(joinpath(examples_dir(), "special_elixirs",
+                                                "elixir_euler_ad.jl"))
     end
 end
 end
diff --git a/test/test_structured_2d.jl b/test/test_structured_2d.jl
index 17ba001d5ec..96202e00f58 100644
--- a/test/test_structured_2d.jl
+++ b/test/test_structured_2d.jl
@@ -194,7 +194,10 @@ end
 @trixi_testset "elixir_advection_restart.jl" begin
     @test_trixi_include(joinpath(EXAMPLES_DIR, "elixir_advection_restart.jl"),
                         l2=[4.219208035582454e-6],
-                        linf=[3.438434404412494e-5])
+                        linf=[3.438434404412494e-5],
+                        # With the default `maxiters = 1` in coverage tests,
+                        # there would be no time steps after the restart.
+                        coverage_override=(maxiters = 100_000,))
     # Ensure that we do not have excessive memory allocations
     # (e.g., from type instabilities)
     let
@@ -211,7 +214,10 @@ end
                         linf=[0.0015194252169410394],
                         rtol=5.0e-5, # Higher tolerance to make tests pass in CI (in particular with macOS)
                         elixir_file="elixir_advection_waving_flag.jl",
-                        restart_file="restart_000021.h5")
+                        restart_file="restart_000021.h5",
+                        # With the default `maxiters = 1` in coverage tests,
+                        # there would be no time steps after the restart.
+                        coverage_override=(maxiters = 100_000,))
     # Ensure that we do not have excessive memory allocations
     # (e.g., from type instabilities)
     let
@@ -227,7 +233,10 @@ end
                         l2=[7.841217436552029e-15],
                         linf=[1.0857981180834031e-13],
                         elixir_file="elixir_advection_free_stream.jl",
-                        restart_file="restart_000036.h5")
+                        restart_file="restart_000036.h5",
+                        # With the default `maxiters = 1` in coverage tests,
+                        # there would be no time steps after the restart.
+                        coverage_override=(maxiters = 100_000,))
     # Ensure that we do not have excessive memory allocations
     # (e.g., from type instabilities)
     let
diff --git a/test/test_structured_3d.jl b/test/test_structured_3d.jl
index 0213e1a9813..a52c459d6be 100644
--- a/test/test_structured_3d.jl
+++ b/test/test_structured_3d.jl
@@ -62,7 +62,10 @@ end
 @trixi_testset "elixir_advection_restart.jl" begin
     @test_trixi_include(joinpath(EXAMPLES_DIR, "elixir_advection_restart.jl"),
                         l2=[0.0025903889347585777],
-                        linf=[0.018407576968841655])
+                        linf=[0.018407576968841655],
+                        # With the default `maxiters = 1` in coverage tests,
+                        # there would be no time steps after the restart.
+                        coverage_override=(maxiters = 100_000,))
     # Ensure that we do not have excessive memory allocations
     # (e.g., from type instabilities)
     let
diff --git a/test/test_threaded.jl b/test/test_threaded.jl
index 478c90b476a..dbbcbf4c7ce 100644
--- a/test/test_threaded.jl
+++ b/test/test_threaded.jl
@@ -208,7 +208,10 @@ end
                             linf=[0.0015194252169410394],
                             rtol=5.0e-5, # Higher tolerance to make tests pass in CI (in particular with macOS)
                             elixir_file="elixir_advection_waving_flag.jl",
-                            restart_file="restart_000021.h5")
+                            restart_file="restart_000021.h5",
+                            # With the default `maxiters = 1` in coverage tests,
+                            # there would be no time steps after the restart.
+                            coverage_override=(maxiters = 100_000,))
 
         # Ensure that we do not have excessive memory allocations
         # (e.g., from type instabilities)
diff --git a/test/test_tree_3d_advection.jl b/test/test_tree_3d_advection.jl
index 56278629417..ae53a2df52f 100644
--- a/test/test_tree_3d_advection.jl
+++ b/test/test_tree_3d_advection.jl
@@ -27,7 +27,10 @@ end
 @trixi_testset "elixir_advection_restart.jl" begin
     @test_trixi_include(joinpath(EXAMPLES_DIR, "elixir_advection_restart.jl"),
                         l2=[0.00016017848135651983],
-                        linf=[0.0014175368788298393])
+                        linf=[0.0014175368788298393],
+                        # With the default `maxiters = 1` in coverage tests,
+                        # there would be no time steps after the restart.
+                        coverage_override=(maxiters = 100_000,))
     # Ensure that we do not have excessive memory allocations
     # (e.g., from type instabilities)
     let
diff --git a/test/test_trixi.jl b/test/test_trixi.jl
index 245efbc0175..cebe2164ae6 100644
--- a/test/test_trixi.jl
+++ b/test/test_trixi.jl
@@ -33,7 +33,7 @@ macro test_trixi_include(elixir, args...)
     local kwargs = Pair{Symbol, Any}[]
     for arg in args
         if (arg.head == :(=) &&
-            !(arg.args[1] in (:l2, :linf, :atol, :rtol, :coverage_override))
+            !(arg.args[1] in (:l2, :linf, :atol, :rtol, :coverage_override, :skip_coverage))
             && !(coverage && arg.args[1] in keys(coverage_override)))
             push!(kwargs, Pair(arg.args...))
         end
diff --git a/test/test_unit.jl b/test/test_unit.jl
index 20368481607..7f774e11d3b 100644
--- a/test/test_unit.jl
+++ b/test/test_unit.jl
@@ -1374,6 +1374,103 @@ end
 
     @test mesh.boundary_faces[:entire_boundary] == [1, 2]
 end
+
+@testset "trixi_include" begin
+    @trixi_testset "Basic" begin
+        example = """
+            x = 4
+            """
+
+        filename = tempname()
+        try
+            open(filename, "w") do file
+                write(file, example)
+            end
+
+            # Use `@trixi_testset`, which wraps code in a temporary module, and call
+            # `trixi_include` with `@__MODULE__` in order to isolate this test.
+            @test_warn "You just called" trixi_include(@__MODULE__, filename)
+            @test @isdefined x
+            @test x == 4
+
+            @test_warn "You just called" trixi_include(@__MODULE__, filename, x = 7)
+            @test x == 7
+
+            @test_throws "assignment `y` not found in expression" trixi_include(@__MODULE__,
+                                                                                filename,
+                                                                                y = 3)
+        finally
+            rm(filename, force = true)
+        end
+    end
+
+    @trixi_testset "With `solve` Without `maxiters`" begin
+        # `trixi_include` assumes this to be the `solve` function of OrdinaryDiffEq,
+        # and therefore tries to insert the kwarg `maxiters`, which will fail here.
+        example = """
+            solve() = 0
+            x = solve()
+            """
+
+        filename = tempname()
+        try
+            open(filename, "w") do file
+                write(file, example)
+            end
+
+            # Use `@trixi_testset`, which wraps code in a temporary module, and call
+            # `trixi_include` with `@__MODULE__` in order to isolate this test.
+            @test_throws "no method matching solve(; maxiters::Int64)" trixi_include(@__MODULE__,
+                                                                                     filename)
+
+            @test_throws "no method matching solve(; maxiters::Int64)" trixi_include(@__MODULE__,
+                                                                                     filename,
+                                                                                     maxiters = 3)
+        finally
+            rm(filename, force = true)
+        end
+    end
+
+    @trixi_testset "With `solve` with `maxiters`" begin
+        # We need another example file that we include with `Base.include` first, in order to
+        # define the `solve` method without `trixi_include` trying to insert `maxiters` kwargs.
+        # Then, we can test that `trixi_include` inserts the kwarg in the `solve()` call.
+        example1 = """
+            solve(; maxiters=0) = maxiters
+            """
+
+        example2 = """
+            x = solve()
+            """
+
+        filename1 = tempname()
+        filename2 = tempname()
+        try
+            open(filename1, "w") do file
+                write(file, example1)
+            end
+            open(filename2, "w") do file
+                write(file, example2)
+            end
+
+            # Use `@trixi_testset`, which wraps code in a temporary module, and call
+            # `Base.include` and `trixi_include` with `@__MODULE__` in order to isolate this test.
+            Base.include(@__MODULE__, filename1)
+            @test_warn "You just called" trixi_include(@__MODULE__, filename2)
+            @test @isdefined x
+            # This is the default `maxiters` inserted by `trixi_include`
+            @test x == 10^5
+
+            @test_warn "You just called" trixi_include(@__MODULE__, filename2,
+                                                       maxiters = 7)
+            # Test that `maxiters` got overwritten
+            @test x == 7
+        finally
+            rm(filename1, force = true)
+            rm(filename2, force = true)
+        end
+    end
+end
 end
 
 end #module
diff --git a/test/test_unstructured_2d.jl b/test/test_unstructured_2d.jl
index d4416ac5b6a..5341d86a7d1 100644
--- a/test/test_unstructured_2d.jl
+++ b/test/test_unstructured_2d.jl
@@ -129,7 +129,10 @@ end
                             0.005243995459478956,
                             0.004685630332338153,
                             0.01750217718347713,
-                        ])
+                        ],
+                        # With the default `maxiters = 1` in coverage tests,
+                        # there would be no time steps after the restart.
+                        coverage_override=(maxiters = 100_000,))
     # Ensure that we do not have excessive memory allocations
     # (e.g., from type instabilities)
     let
diff --git a/test/test_visualization.jl b/test/test_visualization.jl
index 48164a70fb3..6444dc91d5d 100644
--- a/test/test_visualization.jl
+++ b/test/test_visualization.jl
@@ -243,7 +243,6 @@ end
     @test_nowarn_mod trixi_include(@__MODULE__,
                                    joinpath(examples_dir(), "tree_2d_dgsem",
                                             "elixir_advection_basic.jl"),
-                                   tspan = (0, 0.1),
                                    analysis_callback = Trixi.TrivialCallback())
     @test adapt_to_mesh_level(sol, 5) isa Tuple
 
@@ -259,7 +258,6 @@ end
     @test_nowarn_mod trixi_include(@__MODULE__,
                                    joinpath(examples_dir(), "tree_3d_dgsem",
                                             "elixir_advection_basic.jl"),
-                                   tspan = (0, 0.1),
                                    analysis_callback = Trixi.TrivialCallback(),
                                    initial_refinement_level = 1)
     @test PlotData2D(sol) isa Trixi.PlotData2DCartesian
@@ -288,8 +286,7 @@ end
 
     @test_nowarn_mod trixi_include(@__MODULE__,
                                    joinpath(examples_dir(), "structured_3d_dgsem",
-                                            "elixir_advection_basic.jl"),
-                                   tspan = (0, 0.1))
+                                            "elixir_advection_basic.jl"))
 
     @testset "1D plot from 3D solution and general mesh" begin
         @testset "Create 1D plot as slice" begin