Better error message when given bad path

src/serialization/ExcelACSets.jl

@@ -45,6 +45,9 @@ installed and imported.
   to Excel table specifications
 """
 function read_xlsx_acset(cons, source::Union{AbstractString,IO}; kw...)
+  if typeof(source) <: AbstractString
+    ispath(source) || error("$(source) is not a valid path to a file")
+  end
   read_acset(cons, read_xlsx(source); kw...)
 end
 

src/serialization/JSONACSets.jl

@@ -84,6 +84,7 @@ end
 Inverse to [`write_json_acset`](@ref).
 """
 function read_json_acset(ty, fname::AbstractString)
+  ispath(fname) || error("$(fname) is not a valid path to a file")
   parse_json_acset(ty, JSON3.read(fname))
 end
 
@@ -164,6 +165,7 @@ Similar to [`parse_json_acset_schema`](@ref) except reads from a file.
 Inverse to [`write_json_acset_schema`](@ref).
 """
 function read_json_acset_schema(T, fname::AbstractString)
+  ispath(fname) || error("$(fname) is not a valid path to a file")
   parse_json_acset_schema(T, JSON3.read(fname))
 end
 

test/serialization/ExcelACSets.jl

@@ -104,4 +104,9 @@ result = read_xlsx_acset(LabeledGraph{String}, labeled_graph_path, tables=(
 ))
 @test result == g
 
+# General functionality
+# ---------------------
+
+@test_throws Exception read_xlsx_acset(LabeledGraph{String}, "badpath.json")
+
 end

test/serialization/JSONACSets.jl

@@ -52,6 +52,8 @@ add_parts!(ldds, :X, 4, Φ=[2,3,4,1], label=[AttrVar(1), :a, :b, AttrVar(2)])
 json = generate_json_acset(ldds)
 @test all(row -> haskey(row, :_id), json[:Label])
 
+@test_throws Exception read_json_acset(Graph, "badfile.json")
+
 # Schema serialization
 ######################
 
@@ -71,4 +73,6 @@ for schema in [SchGraph, SchWeightedGraph, SchLabeledDDS]
   @test roundtrip_json_acset_schema(schema) == schema
 end
 
+@test_throws Exception read_json_acset_schema(BasicSchema, "badfile.json")
+
 end