Consolidate FileDFG tests

[Affie]

lGTM, we should just consolidate FileDFG tests with this (i started updating it) at some stage:

DistributedFactorGraphs.jl/test/testBlocks.jl

Lines 1511 to 1578 in 2b68259

	function FileDFGTestBlock(testDFGAPI; kwargs...)
	# testDFGAPI = LightDFG
	# kwargs = ()
	# filename = "/tmp/fileDFG"
	dfg, verts, facs = connectivityTestGraph(testDFGAPI; kwargs...)
	for filename in ["/tmp/fileDFG", "/tmp/FileDFGExtension.tar.gz"]
	v4 = getVariable(dfg, :x4)
	vnd = getSolverData(v4)
	# set everything
	vnd.BayesNetVertID = :outid
	push!(vnd.BayesNetOutVertIDs, :id)
	vnd.bw[1] = 1.0
	push!(vnd.dimIDs, 1)
	vnd.dims = 1
	vnd.dontmargin = true
	vnd.eliminated = true
	vnd.inferdim = 1.5
	vnd.initialized = true
	vnd.ismargin = true
	push!(vnd.separator, :sep)
	vnd.solveInProgress = 1
	vnd.solvedCount = 2
	vnd.val .= 2.0
	#update
	updateVariable!(dfg, v4)
	f45 = getFactor(dfg, :x4x5f1)
	fsd = f45.solverData
	# set some factor solver data
	push!(fsd.certainhypo, 2)
	push!(fsd.edgeIDs, 3)
	fsd.eliminated = true
	push!(fsd.multihypo, 4.0)
	fsd.nullhypo = 5.0
	fsd.potentialused = true
	fsd.solveInProgress = true
	#update factor
	updateFactor!(dfg, f45)
	# Save and load the graph to test.
	saveDFG(dfg, filename)
	retDFG = testDFGAPI(userId="testUserId")
	@info "Going to load $filename"
	@test_throws AssertionError loadDFG!(retDFG,"badfilename")
	loadDFG!(retDFG, filename)
	@test issetequal(ls(dfg), ls(retDFG))
	@test issetequal(lsf(dfg), lsf(retDFG))
	for var in ls(dfg)
	@test getVariable(dfg, var) == getVariable(retDFG, var)
	end
	for fact in lsf(dfg)
	@test getFactor(dfg, fact) == getFactor(retDFG, fact)
	end
	# @test length(getDataEntries(getVariable(retDFG, :x1))) == 1
	# @test typeof(getDataEntry(getVariable(retDFG, :x1),:testing)) == GeneralDataEntry
	# @test length(getDataEntries(getVariable(retDFG, :x2))) == 1
	# @test typeof(getDataEntry(getVariable(retDFG, :x2),:testing2)) == FileDataEntry
	end
	end

Originally posted by @Affie in #625 (comment)