diff --git a/src/dataset.jl b/src/dataset.jl
index a68da81..207e3a4 100644
--- a/src/dataset.jl
+++ b/src/dataset.jl
@@ -169,6 +169,10 @@ function Base.setindex!(ds::AbstractDataset,data::AbstractVariable,varname::Symb
 end
 
 
+function Base.haskey(ds::AbstractDataset,varname::SymbolOrString)
+    return Symbol(varname) in Symbol.(keys(ds))
+end
+
 """
     varbyattrib(ds, attname = attval)
 
diff --git a/test/memory_dataset.jl b/test/memory_dataset.jl
index 0dec0ba..3becb7f 100644
--- a/test/memory_dataset.jl
+++ b/test/memory_dataset.jl
@@ -101,7 +101,6 @@ CDM.dimnames(v::MemoryVariable) = v.dimnames
 CDM.dataset(v::MemoryVariable) = v.parent_dataset
 
 Base.keys(md::MemoryDataset) = keys(md.variables)
-Base.haskey(md::MemoryDataset,varname::SymbolOrString) = haskey(md.variables,String(varname))
 CDM.variable(md::MemoryDataset,varname::SymbolOrString) = md.variables[String(varname)]
 CDM.dimnames(md::MemoryDataset) = keys(md.dimensions)
 CDM.maskingvalue(md::MemoryDataset) = md.maskingvalue
diff --git a/test/test_multifile.jl b/test/test_multifile.jl
index 0178c72..b4575dc 100644
--- a/test/test_multifile.jl
+++ b/test/test_multifile.jl
@@ -3,7 +3,19 @@ using Test
 import CommonDataModel as CDM
 using DataStructures
 using Dates
-import CommonDataModel: AbstractDataset, AbstractVariable, Attributes, Dimensions, CatArrays, defGroup, sync, chunking, deflate, checksum
+import CommonDataModel:
+    @CF_str,
+    AbstractDataset,
+    AbstractVariable,
+    Attributes,
+    CatArrays,
+    Dimensions,
+    checksum,
+    chunking,
+    defGroup,
+    deflate,
+    fillvalue,
+    sync
 
 function example_file(TDS,i,array, fname = tempname();
     varname = "var")
@@ -126,6 +138,8 @@ for deferopen in (false,true)
     local buf, ds_merged, fname_merged, var
 
     mfds = TDS(fnames, deferopen = deferopen);
+
+    @test haskey(mfds,varname)
     var = variable(mfds,varname);
     data = var[:,:,:]
     @test C == var[:,:,:]