"show" method throws an error for models with no tracers

[glwagner]

Actually, the problem looks like its with the method has_velocities. I got this error:

ERROR: BoundsError: attempt to access ()
  at index [1]
Stacktrace:
 [1] getindex(::Tuple, ::Int64) at ./tuple.jl:24
 [2] has_velocities(::Tuple{}) at /Users/gregorywagner/.julia/packages/Oceananigans/Lzkia/src/Fields/field_tuples.jl:101
 [3] tracernames(::Tuple{}) at /Users/gregorywagner/.julia/packages/Oceananigans/Lzkia/src/Fields/field_tuples.jl:105
 [4] tracernames(::NamedTuple{(),Tuple{}}) at /Users/gregorywagner/.julia/packages/Oceananigans/Lzkia/src/Fields/field_tuples.jl:106
 [5] show(::IOContext{REPL.Terminals.TTYTerminal}, ::IncompressibleModel{Oceananigans.TimeSteppers.AdamsBashforthTimeStepper{Float64,NamedTuple{(:u, :v, :w),Tuple{Field{Oceananigans.Face,Oceananigans.Cell,Oceananigans.Cell,OffsetArrays.OffsetArray{Float64,3,Array{Float64,3}},RegularCartesianGrid{Float64,Periodic,Flat,Bounded,StepRangeLen{Float64,Base.TwicePrecision{Float64},Base.TwicePrecision{Float64}}},NamedTuple{(:x, :y, :z),Tuple{CoordinateBoundaryConditions{BoundaryCondition{Oceananigans.BoundaryConditions.Periodic,Nothing},BoundaryCondition{Oceananigans.BoundaryConditions.Periodic,Nothing}},CoordinateBoundaryConditions{BoundaryCondition{Oceananigans.BoundaryConditions.Periodic,Nothing},BoundaryCondition{Oceananigans.BoundaryConditions.Periodic,Nothing}},CoordinateBoundaryConditions{BoundaryCondition{Flux,Nothing},BoundaryCondition{Flux,Nothing}}}}},Field{Oceananigans.Cell,Oceananigans.Face,Oceananigans.Cell,OffsetArrays.OffsetArray{Float64,3,Array{Float64,3}},RegularCartesianGrid{Float64,Periodic,Flat,Bounded,StepRangeLen{Float64,Base.TwicePrecision{Float64},Base.TwicePrecision{Float64}}},NamedTuple{(:x, :y, :z),Tuple{CoordinateBoundaryConditions{BoundaryCondition{Oceananigans.BoundaryConditions.Periodic,Nothing},BoundaryCondition{Oceananigans.BoundaryConditions.Periodic,Nothing}},CoordinateBoundaryConditions{BoundaryCondition{Oceananigans.BoundaryConditions.Periodic,Nothing},BoundaryCondition{Oceananigans.BoundaryConditions.Periodic,Nothing}},CoordinateBoundaryConditions{BoundaryCondition{Flux,Nothing},BoundaryCondition{Flux,Nothing}}}}},Field{Oceananigans.Cell,Oceananigans.Cell,Oceananigans.Face,OffsetArrays.OffsetArray{Float64,3,Array{Float64,3}},RegularCartesianGrid{Float64,Periodic,Flat,Bounded,StepRangeLen{Float64,Base.TwicePrecision{Float64},Base.TwicePrecision{Float64}}},NamedTuple{(:x, :y, :z),Tuple{CoordinateBoundaryConditions{BoundaryCondition{Oceananigans.BoundaryConditions.Periodic,Nothing},BoundaryCondition{Oceananigans.BoundaryConditions.Periodic,Nothing}},CoordinateBoundaryConditions{BoundaryCondition{Oceananigans.BoundaryConditions.Periodic,Nothing},BoundaryCondition{Oceananigans.BoundaryConditions.Periodic,Nothing}},CoordinateBoundaryConditions{BoundaryCondition{NoPenetration,Nothing},BoundaryCondition{NoPenetration,Nothing}}}}}}},NamedTuple{(:u, :v, :w),Tuple{Field{Oceananigans.Face,Oceananigans.Cell,Oceananigans.Cell,OffsetArrays.OffsetArray{Float64,3,Array{Float64,3}},RegularCartesianGrid{Float64,Periodic,Flat,Bounded,StepRangeLen{Float64,Base.TwicePrecision{Float64},Base.TwicePrecision{Float64}}},NamedTuple{(:x, :y, :z),Tuple{CoordinateBoundaryConditions{BoundaryCondition{Oceananigans.BoundaryConditions.Periodic,Nothing},BoundaryCondition{Oceananigans.BoundaryConditions.Periodic,Nothing}},CoordinateBoundaryConditions{BoundaryCondition{Oceananigans.BoundaryConditions.Periodic,Nothing},BoundaryCondition{Oceananigans.BoundaryConditions.Periodic,Nothing}},CoordinateBoundaryConditions{BoundaryCondition{Value,Int64},BoundaryCondition{Value,BoundaryFunction{:y,Oceananigans.Face,Oceananigans.Cell,var"#47#50",Nothing}}}}}},Field{Oceananigans.Cell,Oceananigans.Face,Oceananigans.Cell,OffsetArrays.OffsetArray{Float64,3,Array{Float64,3}},RegularCartesianGrid{Float64,Periodic,Flat,Bounded,StepRangeLen{Float64,Base.TwicePrecision{Float64},Base.TwicePrecision{Float64}}},NamedTuple{(:x, :y, :z),Tuple{CoordinateBoundaryConditions{BoundaryCondition{Oceananigans.BoundaryConditions.Periodic,Nothing},BoundaryCondition{Oceananigans.BoundaryConditions.Periodic,Nothing}},CoordinateBoundaryConditions{BoundaryCondition{Oceananigans.BoundaryConditions.Periodic,Nothing},BoundaryCondition{Oceananigans.BoundaryConditions.Periodic,Nothing}},CoordinateBoundaryConditions{BoundaryCondition{Flux,Nothing},BoundaryCondition{Flux,Nothing}}}}},Field{Oceananigans.Cell,Oceananigans.Cell,Oceananigans.Face,OffsetArrays.OffsetArray{Float64,3,Array{Float64,3}},RegularCartesianGrid{Float64,Periodic,Flat,Bounded,StepRangeLen{Float64,Base.TwicePrecision{Float64},Base.TwicePrecision{Float64}}},NamedTuple{(:x, :y, :z),Tuple{CoordinateBoundaryConditions{BoundaryCondition{Oceananigans.BoundaryConditions.Periodic,Nothing},BoundaryCondition{Oceananigans.BoundaryConditions.Periodic,Nothing}},CoordinateBoundaryConditions{BoundaryCondition{Oceananigans.BoundaryConditions.Periodic,Nothing},BoundaryCondition{Oceananigans.BoundaryConditions.Periodic,Nothing}},CoordinateBoundaryConditions{BoundaryCondition{NoPenetration,Nothing},BoundaryCondition{NoPenetration,Nothing}}}}}}}},ConstantIsotropicDiffusivity{Float64,NamedTuple{(),Tuple{}}},CPU,RegularCartesianGrid{Float64,Periodic,Flat,Bounded,StepRangeLen{Float64,Base.TwicePrecision{Float64},Base.TwicePrecision{Float64}}},Float64,Nothing,Nothing,Nothing,NamedTuple{(:u, :v, :w),Tuple{Field{Oceananigans.Face,Oceananigans.Cell,Oceananigans.Cell,OffsetArrays.OffsetArray{Float64,3,Array{Float64,3}},RegularCartesianGrid{Float64,Periodic,Flat,Bounded,StepRangeLen{Float64,Base.TwicePrecision{Float64},Base.TwicePrecision{Float64}}},NamedTuple{(:x, :y, :z),Tuple{CoordinateBoundaryConditions{BoundaryCondition{Oceananigans.BoundaryConditions.Periodic,Nothing},BoundaryCondition{Oceananigans.BoundaryConditions.Periodic,Nothing}},CoordinateBoundaryConditions{BoundaryCondition{Oceananigans.BoundaryConditions.Periodic,Nothing},BoundaryCondition{Oceananigans.BoundaryConditions.Periodic,Nothing}},CoordinateBoundaryConditions{BoundaryCondition{Value,Int64},BoundaryCondition{Value,BoundaryFunction{:y,Oceananigans.Face,Oceananigans.Cell,var"#47#50",Nothing}}}}}},Field{Oceananigans.Cell,Oceananigans.Face,Oceananigans.Cell,OffsetArrays.OffsetArray{Float64,3,Array{Float64,3}},RegularCartesianGrid{Float64,Periodic,Flat,Bounded,StepRangeLen{Float64,Base.TwicePrecision{Float64},Base.TwicePrecision{Float64}}},NamedTuple{(:x, :y, :z),Tuple{CoordinateBoundaryConditions{BoundaryCondition{Oceananigans.BoundaryConditions.Periodic,Nothing},BoundaryCondition{Oceananigans.BoundaryConditions.Periodic,Nothing}},CoordinateBoundaryConditions{BoundaryCondition{Oceananigans.BoundaryConditions.Periodic,Nothing},BoundaryCondition{Oceananigans.BoundaryConditions.Periodic,Nothing}},CoordinateBoundaryConditions{BoundaryCondition{Flux,Nothing},BoundaryCondition{Flux,Nothing}}}}},Field{Oceananigans.Cell,Oceananigans.Cell,Oceananigans.Face,OffsetArrays.OffsetArray{Float64,3,Array{Float64,3}},RegularCartesianGrid{Float64,Periodic,Flat,Bounded,StepRangeLen{Float64,Base.TwicePrecision{Float64},Base.TwicePrecision{Float64}}},NamedTuple{(:x, :y, :z),Tuple{CoordinateBoundaryConditions{BoundaryCondition{Oceananigans.BoundaryConditions.Periodic,Nothing},BoundaryCondition{Oceananigans.BoundaryConditions.Periodic,Nothing}},CoordinateBoundaryConditions{BoundaryCondition{Oceananigans.BoundaryConditions.Periodic,Nothing},BoundaryCondition{Oceananigans.BoundaryConditions.Periodic,Nothing}},CoordinateBoundaryConditions{BoundaryCondition{NoPenetration,Nothing},BoundaryCondition{NoPenetration,Nothing}}}}}}},NamedTuple{(),Tuple{}},NamedTuple{(:pHY′, :pNHS),Tuple{Field{Oceananigans.Cell,Oceananigans.Cell,Oceananigans.Cell,OffsetArrays.OffsetArray{Float64,3,Array{Float64,3}},RegularCartesianGrid{Float64,Periodic,Flat,Bounded,StepRangeLen{Float64,Base.TwicePrecision{Float64},Base.TwicePrecision{Float64}}},NamedTuple{(:x, :y, :z),Tuple{CoordinateBoundaryConditions{BoundaryCondition{Oceananigans.BoundaryConditions.Periodic,Nothing},BoundaryCondition{Oceananigans.BoundaryConditions.Periodic,Nothing}},CoordinateBoundaryConditions{BoundaryCondition{Oceananigans.BoundaryConditions.Periodic,Nothing},BoundaryCondition{Oceananigans.BoundaryConditions.Periodic,Nothing}},CoordinateBoundaryConditions{BoundaryCondition{Flux,Nothing},BoundaryCondition{Flux,Nothing}}}}},Field{Oceananigans.Cell,Oceananigans.Cell,Oceananigans.Cell,OffsetArrays.OffsetArray{Float64,3,Array{Float64,3}},RegularCartesianGrid{Float64,Periodic,Flat,Bounded,StepRangeLen{Float64,Base.TwicePrecision{Float64},Base.TwicePrecision{Float64}}},NamedTuple{(:x, :y, :z),Tuple{CoordinateBoundaryConditions{BoundaryCondition{Oceananigans.BoundaryConditions.Periodic,Nothing},BoundaryCondition{Oceananigans.BoundaryConditions.Periodic,Nothing}},CoordinateBoundaryConditions{BoundaryCondition{Oceananigans.BoundaryConditions.Periodic,Nothing},BoundaryCondition{Oceananigans.BoundaryConditions.Periodic,Nothing}},CoordinateBoundaryConditions{BoundaryCondition{Flux,Nothing},BoundaryCondition{Flux,Nothing}}}}}}},NamedTuple{(:u, :v, :w),Tuple{SimpleForcing{Oceananigans.Face,Oceananigans.Cell,Oceananigans.Cell,var"#45#48",Nothing},typeof(Oceananigans.Forcing.zeroforcing),SimpleForcing{Oceananigans.Cell,Oceananigans.Cell,Oceananigans.Face,var"#46#49",Nothing}}},Oceananigans.Solvers.PressureSolver{Oceananigans.Solvers.HorizontallyPeriodic,CPU,NamedTuple{(:kx², :ky², :kz²),Tuple{Array{Float64,3},Array{Float64,3},Array{Float64,3}}},Array{Complex{Float64},3},NamedTuple{(:FFTxy!, :DCTz!, :IFFTxy!, :IDCTz!),Tuple{FFTW.cFFTWPlan{Complex{Float64},-1,true,3},FFTW.r2rFFTWPlan{Complex{Float64},(5,),true,3},AbstractFFTs.ScaledPlan{Complex{Float64},FFTW.cFFTWPlan{Complex{Float64},1,true,3},Float64},FFTW.r2rFFTWPlan{Complex{Float64},(4,),true,3}}},Nothing},Nothing}) at /Users/gregorywagner/.julia/packages/Oceananigans/Lzkia/src/Models/show_models.jl:5

[ali-ramadhan]

Hmmm, yeah one issue is that we don't actually test show methods. Perhaps it would be good to add a bunch of show tests which would also increase code coverage.