Update more tests

Author: YingboMa

test/clock.jl

@@ -67,7 +67,7 @@ ci, varmap = infer_clocks(sys)
 eqmap = ci.eq_domain
 tss, inputs = ModelingToolkit.split_system(deepcopy(ci))
 sss, = SystemStructures._structural_simplify!(deepcopy(tss[1]), (inputs[1], ()))
-@test equations(sss) == [D(x) ~ u - y]
+@test equations(sss) == [D(x) ~ u - x]
 sss, = SystemStructures._structural_simplify!(deepcopy(tss[2]), (inputs[2], ()))
 @test isempty(equations(sss))
 @test observed(sss) == [yd ~ Sample(t, dt)(y); r ~ 1.0; ud ~ kp * (r - yd)]

test/reduction.jl

@@ -294,7 +294,7 @@ ss = structural_simplify(sys)
 @test isempty(equations(ss))
 @test sort(string.(observed(ss))) == ["x(t) ~ 0.0"
     "xˍt(t) ~ 0.0"
-    "y(t) ~ xˍt(t)"]
+    "y(t) ~ xˍt(t) - x(t)"]
 
 eqs = [D(D(x)) ~ -x]
 @named sys = ODESystem(eqs, t, [x], [])

test/structural_transformation/tearing.jl

@@ -138,11 +138,6 @@ eqs = [
     0 ~ x + z,
 ]
 @named nlsys = NonlinearSystem(eqs, [x, y, z], [])
-let (mm, _, _) = ModelingToolkit.aag_bareiss(nlsys)
-    @test mm == [-1 1 0;
-        0 -1 -1;
-        0 0 0]
-end
 
 newsys = tearing(nlsys)
 @test length(equations(newsys)) <= 1