allow fill value for defVar

Author: Alexander-Barth

src/variable.jl

@@ -45,9 +45,13 @@ eachchunk(v::CFVariable{T,N,<:ZarrVariable}) where {T,N} = eachchunk(v.var)
 haschunks(v::CFVariable{T,N,<:ZarrVariable}) where {T,N} = haschunks(v.var)
 
 
-function CDM.defVar(ds::ZarrDataset,name::SymbolOrString,vtype::DataType,dimensionnames; chunksizes=nothing, attrib = Dict(), kwargs...)
+function CDM.defVar(ds::ZarrDataset,name::SymbolOrString,vtype::DataType,dimensionnames; chunksizes=nothing, attrib = Dict(), fillvalue = nothing, kwargs...)
     @assert iswritable(ds)
 
+    if isnothing(fillvalue)
+        fillvalue = get(attrib,"_FillValue",nothing)
+    end
+
     _attrib = Dict(attrib)
     _attrib["_ARRAY_DIMENSIONS"] = reverse(dimensionnames)
 
@@ -62,6 +66,7 @@ function CDM.defVar(ds::ZarrDataset,name::SymbolOrString,vtype::DataType,dimensi
         vtype, ds.zgroup, name, _size...;
         chunks = chunksizes,
         attrs = _attrib,
+        fill_value = fillvalue,
         kwargs...
     )
 

test/test_write.jl

@@ -44,3 +44,17 @@ io = IOBuffer()
 show(io,ds)
 str = String(take!(io))
 @test occursin("Global",str)
+
+
+# fill value
+
+fname = tempname()
+ds = ZarrDataset(fname,"c")
+defDim(ds,"lon",100)
+v = defVar(ds,"lon",Float32,("lon",),fillvalue = 9999.)
+v .= 1
+close(ds)
+
+ds = ZarrDataset(fname)
+@test eltype(ds["lon"]) ==  Union{Missing, Float32}
+@test eltype(cfvariable(ds,"lon",fillvalue=nothing)) == Float32