Add test for Adami Pressure Extrapolation.

[RubberLanding]

Add test for Adami Pressure Extrapolation.

[efaulhaber]

I think it would make more sense to restructure the test like this:

@testset "Pressure Extrapolation Adami" begin
    particle_spacing = 0.1
    n_particles = 4
    n_layers = 3
    ...

    state_equation = ...
    boundary_model = ...
    boundary_system = ...

    @testset "Constant Zero Pressure" begin
        tank1 = ...
        fluid_system1 = ...
        ...
    end

    @testset "Constant Nonzero Pressure" begin
        tank2 = ...
        fluid_system2 = ...
    end

    @testset "Hydrostatic Pressure Gradient" begin
        tank3 = ...
        fluid_system3 = ...
        tank_reference = ...
     end
end

Then you can avoid some duplicate code.

[efaulhaber]

Suggested change

	@testset "Pressure Extrapolation Adami: Constant Pressure" begin
	@testset "Constant Pressure" begin

This is already a subset of "Pressure Extrapolation Adami".

[efaulhaber]

Suggested change

	#=
	Test whether the pressure is constant and 0.0, if the density of the state equation and in the tank are the same.
	=#
	particle_spacing = 0.1
	n_particles = 4
	n_layers = 3
	width = particle_spacing * n_particles
	height = particle_spacing * n_particles
	density = 257
	# In this testset, we verify that pressures in a static tank are extrapolated correctly
	particle_spacing = 0.1
	n_particles = 4
	n_layers = 3
	width = particle_spacing * n_particles
	height = particle_spacing * n_particles
	# Use constant density equal to the reference density of the state equation,
	# so that the pressure is constant zero. Then we test that the extrapolation also yields zero.
	density = 257

[efaulhaber]

Suggested change

viscosity = ViscosityAdami(nu=1e-6)

I would remove the extra complexity of the viscosity here.

[efaulhaber]

Suggested change

	#=
	Test whether the pressure is constant, if the density of the state equation and in the tank are not the same.
	=#
	# Test whether the pressure is constant if the density of the state equation
	# and in the tank are not the same.

[efaulhaber]

This is still the same density, or did I miss something?
Shouldn't this be

Suggested change

	tank2 = RectangularTank(particle_spacing, (width, height), (width, height),
	density, n_layers=n_layers,
	faces=(true, true, true, false))
	density = 310
	tank2 = RectangularTank(particle_spacing, (width, height), (width, height),
	density, n_layers=n_layers,
	faces=(true, true, true, false))

[efaulhaber]

Suggested change

	@test all(boundary_system.boundary_model.pressure .== 0.0) &
	@test all(boundary_system.boundary_model.pressure .== 0.0) &&

[efaulhaber]

You can use v_fluid again, no?

[efaulhaber]

This is only computing the pressure for the fluid system, not for the boundary. I guess it worked because you didn't actually change the density (see my comment above).

[efaulhaber]

Why are you not using the same sizes as before?

[efaulhaber]

Also, the tests are failing.