diff --git a/src/MetagraphOptimization.jl b/src/MetagraphOptimization.jl
index 28a1fbb..039f233 100644
--- a/src/MetagraphOptimization.jl
+++ b/src/MetagraphOptimization.jl
@@ -2,6 +2,7 @@ module MetagraphOptimization
 import Base.show
 import Base.==
 import Base.in
+import Base.copy
 
 include("tasks.jl")
 include("nodes.jl")
@@ -16,7 +17,7 @@ include("utility.jl")
 export Node, Edge, ComputeTaskNode, DataTaskNode, DAG
 export AbstractTask, AbstractComputeTask, AbstractDataTask, DataTask, ComputeTaskP, ComputeTaskS1, ComputeTaskS2, ComputeTaskV, ComputeTaskU, ComputeTaskSum, FusedComputeTask
 export make_node, make_edge, insert_node, insert_edge, is_entry_node, is_exit_node, parents, children, compute, graph_properties, get_exit_node, is_valid
-export NodeFusion, NodeReduction, NodeSplit, push_operation!, pop_operation!, generate_options
+export NodeFusion, NodeReduction, NodeSplit, push_operation!, pop_operation!, can_pop, reset_graph!, generate_options
 export import_txt
 
 export ==, in, show
diff --git a/src/graph_functions.jl b/src/graph_functions.jl
index 6e90894..5b853ae 100644
--- a/src/graph_functions.jl
+++ b/src/graph_functions.jl
@@ -75,7 +75,7 @@ function insert_edge!(graph::DAG, edge::Edge, track=true)
    push!(edge.edge[1].parents, edge.edge[2])
    push!(edge.edge[2].children, edge.edge[1])
 
-   if (track) push!(graph.diff.addedEdges) end
+   if (track) push!(graph.diff.addedEdges, edge) end
    return edge
 end
 
@@ -97,7 +97,6 @@ end
 # return the graph "difference" since last time this function was called
 function get_snapshot_diff(graph::DAG)
    return swapfield!(graph, :diff, Diff())
-   return result
 end
 
 function graph_properties(graph::DAG)
diff --git a/src/graph_operations.jl b/src/graph_operations.jl
index 1f14a4c..9e69ff9 100644
--- a/src/graph_operations.jl
+++ b/src/graph_operations.jl
@@ -31,6 +31,15 @@ function pop_operation!(graph::DAG)
 
 end
 
+can_pop(graph::DAG) = !isempty(graph.operationsToApply) || !isempty(graph.appliedOperations)
+
+# reset the graph to its initial state with no operations applied
+function reset_graph!(graph::DAG)
+   while (can_pop(graph))
+      pop_operation!(graph)
+   end
+end
+
 # implementation detail functions, don't export
 
 # applies all unapplied operations in the DAG
@@ -63,7 +72,7 @@ function apply_operation!(graph::DAG, operation::NodeReduction)
 end
 
 function apply_operation!(graph::DAG, operation::NodeSplit)
-   diff = node_split!(graph, operation.input[1])
+   diff = node_split!(graph, operation.input)
    return AppliedNodeSplit(operation, diff)
 end
 
diff --git a/src/node_functions.jl b/src/node_functions.jl
index d907722..ac52206 100644
--- a/src/node_functions.jl
+++ b/src/node_functions.jl
@@ -33,3 +33,7 @@ end
 function ==(e1::Edge, e2::Edge)
     return e1.edge[1] == e2.edge[1] && e1.edge[2] == e2.edge[2]
 end
+
+copy(id::Base.UUID) = Base.UUID(id.value)
+copy(n::ComputeTaskNode) =  ComputeTaskNode(copy(n.task), copy(n.parents), copy(n.children), copy(n.id))
+copy(n::DataTaskNode) = DataTaskNode(copy(n.task), copy(n.parents), copy(n.children), copy(n.id))
diff --git a/src/nodes.jl b/src/nodes.jl
index 3509217..1e529db 100644
--- a/src/nodes.jl
+++ b/src/nodes.jl
@@ -13,6 +13,7 @@ struct DataTaskNode <: Node
    children::Vector{Node}
 
    # need a unique identifier unique to every *constructed* node
+   # however, it can be copied when splitting a node
    id::Base.UUID
 end
 
@@ -24,13 +25,8 @@ struct ComputeTaskNode <: Node
    id::Base.UUID
 end
 
-function DataTaskNode(t::AbstractDataTask)
-   return DataTaskNode(t, Vector{Node}(), Vector{Node}(), UUIDs.uuid1(rng))
-end
-
-function ComputeTaskNode(t::AbstractComputeTask)
-   return ComputeTaskNode(t, Vector{Node}(), Vector{Node}(), UUIDs.uuid1(rng))
-end
+DataTaskNode(t::AbstractDataTask) = DataTaskNode(t, Vector{Node}(), Vector{Node}(), UUIDs.uuid1(rng))
+ComputeTaskNode(t::AbstractComputeTask) = ComputeTaskNode(t, Vector{Node}(), Vector{Node}(), UUIDs.uuid1(rng))
 
 struct Edge
    # edge points from child to parent
diff --git a/src/task_functions.jl b/src/task_functions.jl
index 7d94b00..de8c8f0 100644
--- a/src/task_functions.jl
+++ b/src/task_functions.jl
@@ -67,3 +67,6 @@ end
 function ==(t1::AbstractDataTask, t2::AbstractDataTask)
    return data(t1) == data(t2)
 end
+
+copy(t::DataTask) = DataTask(t.data)
+copy(t::AbstractComputeTask) = typeof(t)()
diff --git a/test/known_graphs.jl b/test/known_graphs.jl
index c17a27a..ac57dbf 100644
--- a/test/known_graphs.jl
+++ b/test/known_graphs.jl
@@ -1,6 +1,9 @@
 using MetagraphOptimization
+using Random
 using Test
 
+Random.seed!(0)
+
 function test_known_graphs()
     g_ABAB = import_txt(joinpath(@__DIR__, "..", "examples", "AB->AB.txt"))
     props = graph_properties(g_ABAB)
@@ -12,6 +15,7 @@ function test_known_graphs()
     @test length(generate_options(g_ABAB).nodeFusions) == 10
 
     test_node_fusion(g_ABAB)
+    test_random_walk(g_ABAB, 100)
 
 
     g_ABAB3 = import_txt(joinpath(@__DIR__, "..", "examples", "AB->ABBB.txt"))
@@ -22,9 +26,10 @@ function test_known_graphs()
     @test props.data == 828
 
     test_node_fusion(g_ABAB3)
+    test_random_walk(g_ABAB3, 1000)
 end
 
-function test_node_fusion(g)
+function test_node_fusion(g::DAG)
     props = graph_properties(g)
 
     options = generate_options(g)
@@ -50,6 +55,47 @@ function test_node_fusion(g)
 
         options = generate_options(g)
     end
-
-    print(g)
+end
+
+function test_random_walk(g::DAG, n::Int64)
+    # the purpose here is to do "random" operations and reverse them again and validate that the graph stays the same and doesn't diverge
+    reset_graph!(g)
+
+    properties = graph_properties(g)
+
+    println("Random Walking... ")
+
+    for i = 1:n
+        print("\r", i)
+        # choose push or pop
+        if rand(Bool)
+            # push
+            opt = generate_options(g)
+
+            # choose one of fuse/split/reduce
+            option = rand(1:3)
+            if option == 1 && !isempty(opt.nodeFusions)
+                push_operation!(g, opt.nodeFusions[rand(1 : length(opt.nodeFusions))])
+            elseif option == 2 && !isempty(opt.nodeReductions)
+                push_operation!(g, opt.nodeReductions[rand(1 : length(opt.nodeReductions))])
+            elseif option == 3 && !isempty(opt.nodeSplits)
+                push_operation!(g, opt.nodeSplits[rand(1 : length(opt.nodeSplits))])
+            else
+                i = i-1
+            end
+        else
+            # pop
+            if (can_pop(g))
+                pop_operation!(g)
+            else
+                i = i-1
+            end
+        end
+    end
+
+    println("\rDone.")
+
+    reset_graph!(g)
+
+    @test properties == graph_properties(g)
 end