add some tests

src/joints.jl

@@ -215,7 +215,7 @@ function Universal(; name, n_a = [1, 0, 0], n_b = [0, 1, 0], phi_a = 0,
  w_a = 0,
  w_b = 0,
  a_a = 0,
- a_b)
+ a_b = 0)
  @named begin
  ptf = PartialTwoFrames()
  revolute_a = Revolute(n = n_a, isroot = false)

test/runtests.jl

@@ -196,7 +196,8 @@ sol2 = solve(prob, Rodas4())
 @test sol2[rev.phi][end]≈-π / 2 rtol=0.01 # pendulum settles at 90 degrees stable equilibrium
 isinteractive() && plot(sol2, idxs = collect(rev.phi))
 
-@info "TODO: write a test that checks that this solution is identical to the one without rod above"
+@test sol2(1:10, idxs=rev.phi).u ≈ sol(1:10, idxs=rev.phi).u atol=1e-3
+
 
 # ==============================================================================
 ## Simple pendulum with rod from absolute rotation ====================================================
@@ -217,19 +218,18 @@ connections = [connect(world.frame_b, rev.frame_a)
 @named model = ODESystem(connections, t, systems = [world, rev, body, damper, rod])
 modele = ModelingToolkit.expand_connections(model)
 
-ssys = structural_simplify(model, allow_parameter = false)
-# ssys = structural_simplify(IRSystem(modele)) # Yingbo, this fails with SymbolicIR but not with MTK
+# ssys = structural_simplify(model, allow_parameter = false)
+ssys = structural_simplify(IRSystem(modele)) # Yingbo, this fails with SymbolicIR but not with MTK
 
 D = Differential(t)
-@test_skip begin # Needs default dummy der
- prob = ODEProblem(ssys, [damper.phi_rel => 1, D(rev.phi) => 0, D(D(rev.phi)) => 0],
- (0, 100), default_dummy_der = 0)
- sol2 = solve(prob, Rodas4())
- @test SciMLBase.successful_retcode(sol2)
- @test minimum(sol2[rev.phi]) > -π
- @test sol2[rev.phi][end]≈-π / 2 rtol=0.01 # pendulum settles at 90 degrees stable equilibrium
- isinteractive() && plot(sol2, idxs = collect(rev.phi))
-end
+
+prob = ODEProblem(ssys, [damper.phi_rel => 1], (0, 100))
+sol3 = solve(prob, Rodas4())
+@test SciMLBase.successful_retcode(sol2)
+@test minimum(sol3[rev.phi]) > -π
+@test sol3[rev.phi][end]≈-π / 2 rtol=0.01 # pendulum settles at 90 degrees stable equilibrium
+isinteractive() && plot(sol3, idxs = rev.phi)
+@test sol3(1:10, idxs=rev.phi).u ≈ sol(1:10, idxs=rev.phi).u atol=1e-2
 
 # ==============================================================================
 ## Double pendulum =============================================================
@@ -766,6 +766,7 @@ defs = [
 ssys = structural_simplify(IRSystem(wheel)) # SymbolicIR chooses 38 states, Yingbo
 prob = ODEProblem(ssys, defs, (0, 10))
 sol = solve(prob, Rodas4(), u0 = prob.u0 .+ 1e-1 .* randn.(), p = prob.p .+ 1e-2 .* randn.()) # TODO: fails to initialize
+@test_broken length(sol.t) > 1
 # isinteractive() && plot(sol, idxs=[cwheel.x, cwheel.y])
 
 # ==============================================================================